diff --git a/.github/scripts/run-librispeech-pruned-transducer-stateless3-2022-05-13.sh b/.github/scripts/run-librispeech-pruned-transducer-stateless3-2022-05-13.sh
index 880767443..ceb77c7c3 100755
--- a/.github/scripts/run-librispeech-pruned-transducer-stateless3-2022-05-13.sh
+++ b/.github/scripts/run-librispeech-pruned-transducer-stateless3-2022-05-13.sh
@@ -27,14 +27,6 @@ ln -s pretrained-iter-1224000-avg-14.pt pretrained.pt
 ln -s pretrained-iter-1224000-avg-14.pt epoch-99.pt
 popd
 
-log "Test exporting to ONNX format"
-
-./pruned_transducer_stateless3/export.py \
-  --exp-dir $repo/exp \
-  --bpe-model $repo/data/lang_bpe_500/bpe.model \
-  --epoch 99 \
-  --avg 1 \
-  --onnx 1
 
 log "Export to torchscript model"
 ./pruned_transducer_stateless3/export.py \
@@ -51,30 +43,8 @@ log "Export to torchscript model"
   --avg 1 \
   --jit-trace 1
 
-ls -lh $repo/exp/*.onnx
 ls -lh $repo/exp/*.pt
 
-log "Decode with ONNX models"
-
-./pruned_transducer_stateless3/onnx_check.py \
-  --jit-filename $repo/exp/cpu_jit.pt \
-  --onnx-encoder-filename $repo/exp/encoder.onnx \
-  --onnx-decoder-filename $repo/exp/decoder.onnx \
-  --onnx-joiner-filename $repo/exp/joiner.onnx \
-  --onnx-joiner-encoder-proj-filename $repo/exp/joiner_encoder_proj.onnx \
-  --onnx-joiner-decoder-proj-filename $repo/exp/joiner_decoder_proj.onnx
-
-./pruned_transducer_stateless3/onnx_pretrained.py \
-  --bpe-model $repo/data/lang_bpe_500/bpe.model \
-  --encoder-model-filename $repo/exp/encoder.onnx \
-  --decoder-model-filename $repo/exp/decoder.onnx \
-  --joiner-model-filename $repo/exp/joiner.onnx \
-  --joiner-encoder-proj-model-filename $repo/exp/joiner_encoder_proj.onnx \
-  --joiner-decoder-proj-model-filename $repo/exp/joiner_decoder_proj.onnx \
-  $repo/test_wavs/1089-134686-0001.wav \
-  $repo/test_wavs/1221-135766-0001.wav \
-  $repo/test_wavs/1221-135766-0002.wav
-
 log "Decode with models exported by torch.jit.trace()"
 
 ./pruned_transducer_stateless3/jit_pretrained.py \
diff --git a/.github/scripts/run-librispeech-pruned-transducer-stateless7-streaming-2022-12-29.sh b/.github/scripts/run-librispeech-pruned-transducer-stateless7-streaming-2022-12-29.sh
index bcbc91a44..2611c8efc 100755
--- a/.github/scripts/run-librispeech-pruned-transducer-stateless7-streaming-2022-12-29.sh
+++ b/.github/scripts/run-librispeech-pruned-transducer-stateless7-streaming-2022-12-29.sh
@@ -22,13 +22,14 @@ tree $repo/
 soxi $repo/test_wavs/*.wav
 ls -lh $repo/test_wavs/*.wav
 
-pushd $repo/exp
+pushd $repo
 git lfs pull --include "data/lang_bpe_500/bpe.model"
 git lfs pull --include "exp/cpu_jit.pt"
 git lfs pull --include "exp/pretrained.pt"
 git lfs pull --include "exp/encoder_jit_trace.pt"
 git lfs pull --include "exp/decoder_jit_trace.pt"
 git lfs pull --include "exp/joiner_jit_trace.pt"
+cd exp
 ln -s pretrained.pt epoch-99.pt
 ls -lh *.pt
 popd
diff --git a/.github/scripts/test-onnx-export.sh b/.github/scripts/test-onnx-export.sh
new file mode 100755
index 000000000..2d5cc6bbf
--- /dev/null
+++ b/.github/scripts/test-onnx-export.sh
@@ -0,0 +1,194 @@
+#!/usr/bin/env bash
+
+set -e
+
+log() {
+  # This function is from espnet
+  local fname=${BASH_SOURCE[1]##*/}
+  echo -e "$(date '+%Y-%m-%d %H:%M:%S') (${fname}:${BASH_LINENO[0]}:${FUNCNAME[1]}) $*"
+}
+
+cd egs/librispeech/ASR
+
+log "=========================================================================="
+repo_url=https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+log "Downloading pre-trained model from $repo_url"
+git lfs install
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained.pt"
+cd exp
+ln -s pretrained.pt epoch-99.pt
+popd
+
+log "Export via torch.jit.trace()"
+
+./pruned_transducer_stateless7_streaming/jit_trace_export.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --use-averaged-model 0 \
+  --epoch 99 \
+  --avg 1 \
+  --decode-chunk-len 32 \
+  --exp-dir $repo/exp/
+
+log "Test exporting to ONNX format"
+
+./pruned_transducer_stateless7_streaming/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --use-averaged-model 0 \
+  --epoch 99 \
+  --avg 1 \
+  --decode-chunk-len 32 \
+  --exp-dir $repo/exp/
+
+ls -lh $repo/exp
+
+log "Run onnx_check.py"
+
+./pruned_transducer_stateless7_streaming/onnx_check.py \
+  --jit-encoder-filename $repo/exp/encoder_jit_trace.pt \
+  --jit-decoder-filename $repo/exp/decoder_jit_trace.pt \
+  --jit-joiner-filename $repo/exp/joiner_jit_trace.pt \
+  --onnx-encoder-filename $repo/exp/encoder-epoch-99-avg-1.onnx \
+  --onnx-decoder-filename $repo/exp/decoder-epoch-99-avg-1.onnx \
+  --onnx-joiner-filename $repo/exp/joiner-epoch-99-avg-1.onnx
+
+log "Run onnx_pretrained.py"
+
+./pruned_transducer_stateless7_streaming/onnx_pretrained.py \
+  --encoder-model-filename $repo/exp/encoder-epoch-99-avg-1.onnx \
+  --decoder-model-filename $repo/exp/decoder-epoch-99-avg-1.onnx \
+  --joiner-model-filename $repo/exp/joiner-epoch-99-avg-1.onnx \
+  --tokens $repo/data/lang_bpe_500/tokens.txt \
+  $repo/test_wavs/1089-134686-0001.wav
+
+rm -rf $repo
+log "--------------------------------------------------------------------------"
+
+log "=========================================================================="
+repo_url=https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+log "Downloading pre-trained model from $repo_url"
+git lfs install
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained-iter-1224000-avg-14.pt"
+
+cd exp
+ln -s pretrained-iter-1224000-avg-14.pt epoch-9999.pt
+popd
+
+log "Export via torch.jit.script()"
+
+./pruned_transducer_stateless3/export.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 9999 \
+  --avg 1 \
+  --exp-dir $repo/exp/ \
+  --jit 1
+
+log "Test exporting to ONNX format"
+
+./pruned_transducer_stateless3/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 9999 \
+  --avg 1 \
+  --exp-dir $repo/exp/
+
+ls -lh $repo/exp
+
+log "Run onnx_check.py"
+
+./pruned_transducer_stateless3/onnx_check.py \
+  --jit-filename $repo/exp/cpu_jit.pt \
+  --onnx-encoder-filename $repo/exp/encoder-epoch-9999-avg-1.onnx \
+  --onnx-decoder-filename $repo/exp/decoder-epoch-9999-avg-1.onnx \
+  --onnx-joiner-filename $repo/exp/joiner-epoch-9999-avg-1.onnx
+
+log "Run onnx_pretrained.py"
+
+./pruned_transducer_stateless3/onnx_pretrained.py \
+  --encoder-model-filename $repo/exp/encoder-epoch-9999-avg-1.onnx \
+  --decoder-model-filename $repo/exp/decoder-epoch-9999-avg-1.onnx \
+  --joiner-model-filename $repo/exp/joiner-epoch-9999-avg-1.onnx \
+  --tokens $repo/data/lang_bpe_500/tokens.txt \
+  $repo/test_wavs/1089-134686-0001.wav \
+  $repo/test_wavs/1221-135766-0001.wav \
+  $repo/test_wavs/1221-135766-0002.wav
+
+rm -rf $repo
+log "--------------------------------------------------------------------------"
+
+
+log "=========================================================================="
+repo_url=https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless5-2022-05-13
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained-epoch-39-avg-7.pt"
+
+cd exp
+ln -s pretrained-epoch-39-avg-7.pt epoch-99.pt
+popd
+
+log "Export via torch.jit.script()"
+
+./pruned_transducer_stateless5/export.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 99 \
+  --avg 1 \
+  --use-averaged-model 0 \
+  --exp-dir $repo/exp \
+  --num-encoder-layers 18 \
+  --dim-feedforward 2048 \
+  --nhead 8 \
+  --encoder-dim 512 \
+  --decoder-dim 512 \
+  --joiner-dim 512 \
+  --jit 1
+
+log "Test exporting to ONNX format"
+
+./pruned_transducer_stateless5/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 99 \
+  --avg 1 \
+  --use-averaged-model 0 \
+  --exp-dir $repo/exp \
+  --num-encoder-layers 18 \
+  --dim-feedforward 2048 \
+  --nhead 8 \
+  --encoder-dim 512 \
+  --decoder-dim 512 \
+  --joiner-dim 512
+
+ls -lh $repo/exp
+
+log "Run onnx_check.py"
+
+./pruned_transducer_stateless5/onnx_check.py \
+  --jit-filename $repo/exp/cpu_jit.pt \
+  --onnx-encoder-filename $repo/exp/encoder-epoch-99-avg-1.onnx \
+  --onnx-decoder-filename $repo/exp/decoder-epoch-99-avg-1.onnx \
+  --onnx-joiner-filename $repo/exp/joiner-epoch-99-avg-1.onnx
+
+log "Run onnx_pretrained.py"
+
+./pruned_transducer_stateless5/onnx_pretrained.py \
+  --encoder-model-filename $repo/exp/encoder-epoch-99-avg-1.onnx \
+  --decoder-model-filename $repo/exp/decoder-epoch-99-avg-1.onnx \
+  --joiner-model-filename $repo/exp/joiner-epoch-99-avg-1.onnx \
+  --tokens $repo/data/lang_bpe_500/tokens.txt \
+  $repo/test_wavs/1089-134686-0001.wav \
+  $repo/test_wavs/1221-135766-0001.wav \
+  $repo/test_wavs/1221-135766-0002.wav
+
+rm -rf $repo
+log "--------------------------------------------------------------------------"
diff --git a/.github/workflows/run-librispeech-pruned-transducer-stateless3-2022-05-13.yml b/.github/workflows/run-librispeech-pruned-transducer-stateless3-2022-05-13.yml
index 2c2bcab0c..f67f7599b 100644
--- a/.github/workflows/run-librispeech-pruned-transducer-stateless3-2022-05-13.yml
+++ b/.github/workflows/run-librispeech-pruned-transducer-stateless3-2022-05-13.yml
@@ -39,7 +39,7 @@ concurrency:
 
 jobs:
   run_librispeech_pruned_transducer_stateless3_2022_05_13:
-    if: github.event.label.name == 'onnx' || github.event.label.name == 'ready' || github.event.label.name == 'run-decode' || github.event_name == 'push' || github.event_name == 'schedule'
+    if: github.event.label.name == 'ready' || github.event.label.name == 'run-decode' || github.event_name == 'push' || github.event_name == 'schedule'
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
diff --git a/.github/workflows/test-onnx-export.yml b/.github/workflows/test-onnx-export.yml
new file mode 100644
index 000000000..c7729dedb
--- /dev/null
+++ b/.github/workflows/test-onnx-export.yml
@@ -0,0 +1,75 @@
+name: test-onnx-export
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    types: [labeled]
+
+  schedule:
+    # minute (0-59)
+    # hour (0-23)
+    # day of the month (1-31)
+    # month (1-12)
+    # day of the week (0-6)
+    # nightly build at 15:50 UTC time every day
+    - cron: "50 15 * * *"
+
+concurrency:
+  group: test_onnx_export-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test_onnx_export:
+    if: github.event.label.name == 'ready' || github.event.label.name == 'onnx' || github.event_name == 'push' || github.event_name == 'schedule'
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        python-version: [3.8]
+      fail-fast: false
+
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: Setup Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: 'pip'
+          cache-dependency-path: '**/requirements-ci.txt'
+
+      - name: Install Python dependencies
+        run: |
+          grep -v '^#' ./requirements-ci.txt  | xargs -n 1 -L 1 pip install
+          pip uninstall -y protobuf
+          pip install --no-binary protobuf protobuf
+
+      - name: Cache kaldifeat
+        id: my-cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/tmp/kaldifeat
+          key: cache-tmp-${{ matrix.python-version }}-2022-09-25
+
+      - name: Install kaldifeat
+        if: steps.my-cache.outputs.cache-hit != 'true'
+        shell: bash
+        run: |
+          .github/scripts/install-kaldifeat.sh
+
+      - name: Test ONNX export
+        shell: bash
+        env:
+          GITHUB_EVENT_NAME: ${{ github.event_name }}
+          GITHUB_EVENT_LABEL_NAME: ${{ github.event.label.name }}
+        run: |
+          export PYTHONPATH=$PWD:$PYTHONPATH
+          export PYTHONPATH=~/tmp/kaldifeat/kaldifeat/python:$PYTHONPATH
+          export PYTHONPATH=~/tmp/kaldifeat/build/lib:$PYTHONPATH
+
+          .github/scripts/test-onnx-export.sh
diff --git a/egs/librispeech/ASR/conformer_ctc3/decode.py b/egs/librispeech/ASR/conformer_ctc3/decode.py
index 8eca2ae02..39186e546 100755
--- a/egs/librispeech/ASR/conformer_ctc3/decode.py
+++ b/egs/librispeech/ASR/conformer_ctc3/decode.py
@@ -58,7 +58,6 @@ For example:
     --left-context 64 \
     --manifest-dir data/fbank_ali
 Note: It supports calculating symbol delay with following decoding methods:
-    - ctc-greedy-search
     - ctc-decoding
     - 1best
 """
@@ -96,10 +95,8 @@ from icefall.decode import (
 from icefall.lexicon import Lexicon
 from icefall.utils import (
     AttributeDict,
-    DecodingResults,
     get_texts,
     get_texts_with_timestamp,
-    make_pad_mask,
     parse_hyp_and_timestamp,
     setup_logger,
     store_transcripts_and_timestamps,
@@ -177,20 +174,18 @@ def get_parser():
         - (0) ctc-decoding. Use CTC decoding. It uses a sentence piece
           model, i.e., lang_dir/bpe.model, to convert word pieces to words.
           It needs neither a lexicon nor an n-gram LM.
-        - (1) ctc-greedy-search. It only use CTC output and a sentence piece
-          model for decoding. It produces the same results with ctc-decoding.
-        - (2) 1best. Extract the best path from the decoding lattice as the
+        - (1) 1best. Extract the best path from the decoding lattice as the
           decoding result.
-        - (3) nbest. Extract n paths from the decoding lattice; the path
+        - (2) nbest. Extract n paths from the decoding lattice; the path
           with the highest score is the decoding result.
-        - (4) nbest-rescoring. Extract n paths from the decoding lattice,
+        - (3) nbest-rescoring. Extract n paths from the decoding lattice,
           rescore them with an n-gram LM (e.g., a 4-gram LM), the path with
           the highest score is the decoding result.
-        - (5) whole-lattice-rescoring. Rescore the decoding lattice with an
+        - (4) whole-lattice-rescoring. Rescore the decoding lattice with an
           n-gram LM (e.g., a 4-gram LM), the best path of rescored lattice
           is the decoding result.
           you have trained an RNN LM using ./rnn_lm/train.py
-        - (6) nbest-oracle. Its WER is the lower bound of any n-best
+        - (5) nbest-oracle. Its WER is the lower bound of any n-best
           rescoring method can achieve. Useful for debugging n-best
           rescoring method.
         """,
@@ -250,6 +245,14 @@ def get_parser():
         help="left context can be seen during decoding (in frames after subsampling)",
     )
 
+    parser.add_argument(
+        "--hlg-scale",
+        type=float,
+        default=0.8,
+        help="""The scale to be applied to `hlg.scores`.
+        """,
+    )
+
     add_model_arguments(parser)
 
     return parser
@@ -270,47 +273,6 @@ def get_decoding_params() -> AttributeDict:
     return params
 
 
-def ctc_greedy_search(
-    ctc_probs: torch.Tensor,
-    nnet_output_lens: torch.Tensor,
-) -> List[List[int]]:
-    """Apply CTC greedy search
-    Args:
-      ctc_probs (torch.Tensor): (batch, max_len, feat_dim)
-      nnet_output_lens (torch.Tensor): (batch, )
-    Returns:
-      List[List[int]]: best path result
-    """
-    topk_prob, topk_index = ctc_probs.topk(1, dim=2)  # (B, maxlen, 1)
-    topk_index = topk_index.squeeze(2)  # (B, maxlen)
-    mask = make_pad_mask(nnet_output_lens)
-    topk_index = topk_index.masked_fill_(mask, 0)  # (B, maxlen)
-    hyps = [hyp.tolist() for hyp in topk_index]
-    scores = topk_prob.max(1)
-    ret_hyps = []
-    timestamps = []
-    for i in range(len(hyps)):
-        hyp, time = remove_duplicates_and_blank(hyps[i])
-        ret_hyps.append(hyp)
-        timestamps.append(time)
-    return ret_hyps, timestamps, scores
-
-
-def remove_duplicates_and_blank(hyp: List[int]) -> Tuple[List[int], List[int]]:
-    # modified from https://github.com/wenet-e2e/wenet/blob/main/wenet/utils/common.py
-    new_hyp: List[int] = []
-    time: List[int] = []
-    cur = 0
-    while cur < len(hyp):
-        if hyp[cur] != 0:
-            new_hyp.append(hyp[cur])
-            time.append(cur)
-        prev = cur
-        while cur < len(hyp) and hyp[cur] == hyp[prev]:
-            cur += 1
-    return new_hyp, time
-
-
 def decode_one_batch(
     params: AttributeDict,
     model: nn.Module,
@@ -402,26 +364,11 @@ def decode_one_batch(
     nnet_output = model.get_ctc_output(encoder_out)
     # nnet_output is (N, T, C)
 
-    if params.decoding_method == "ctc-greedy-search":
-        hyps, timestamps, _ = ctc_greedy_search(
-            nnet_output,
-            encoder_out_lens,
-        )
-        res = DecodingResults(hyps=hyps, timestamps=timestamps)
-        hyps, timestamps = parse_hyp_and_timestamp(
-            res=res,
-            sp=bpe_model,
-            subsampling_factor=params.subsampling_factor,
-            frame_shift_ms=params.frame_shift_ms,
-        )
-        key = "ctc-greedy-search"
-        return {key: (hyps, timestamps)}
-
     supervision_segments = torch.stack(
         (
             supervisions["sequence_idx"],
             supervisions["start_frame"] // params.subsampling_factor,
-            supervisions["num_frames"] // params.subsampling_factor,
+            encoder_out_lens.cpu(),
         ),
         1,
     ).to(torch.int32)
@@ -434,75 +381,6 @@ def decode_one_batch(
         assert bpe_model is not None
         decoding_graph = H
 
-    if params.decoding_method in ["1best", "nbest", "nbest-oracle"]:
-        hlg_scale_list = [0.2, 0.4, 0.6, 0.8, 1.0]
-
-        ori_scores = decoding_graph.scores.clone()
-
-        ans = {}
-        for hlg_scale in hlg_scale_list:
-            decoding_graph.scores = ori_scores * hlg_scale
-            lattice = get_lattice(
-                nnet_output=nnet_output,
-                decoding_graph=decoding_graph,
-                supervision_segments=supervision_segments,
-                search_beam=params.search_beam,
-                output_beam=params.output_beam,
-                min_active_states=params.min_active_states,
-                max_active_states=params.max_active_states,
-                subsampling_factor=params.subsampling_factor,
-            )
-            key_suffix = f"-HLG-scale-{hlg_scale}"
-
-            if params.decoding_method == "nbest-oracle":
-                # Note: You can also pass rescored lattices to it.
-                # We choose the HLG decoded lattice for speed reasons
-                # as HLG decoding is faster and the oracle WER
-                # is only slightly worse than that of rescored lattices.
-                best_path = nbest_oracle(
-                    lattice=lattice,
-                    num_paths=params.num_paths,
-                    ref_texts=supervisions["text"],
-                    word_table=word_table,
-                    nbest_scale=params.nbest_scale,
-                    oov="<UNK>",
-                )
-                hyps = get_texts(best_path)
-                hyps = [[word_table[i] for i in ids] for ids in hyps]
-                key = f"oracle-{params.num_paths}-nbest-scale-{params.nbest_scale}"  # noqa
-                timestamps = [[] for _ in range(len(hyps))]
-                ans[key + key_suffix] = (hyps, timestamps)
-
-            elif params.decoding_method in ["1best", "nbest"]:
-                if params.decoding_method == "1best":
-                    best_path = one_best_decoding(
-                        lattice=lattice,
-                        use_double_scores=params.use_double_scores,
-                    )
-                    key = "no-rescore"
-                    res = get_texts_with_timestamp(best_path)
-                    hyps, timestamps = parse_hyp_and_timestamp(
-                        res=res,
-                        subsampling_factor=params.subsampling_factor,
-                        frame_shift_ms=params.frame_shift_ms,
-                        word_table=word_table,
-                    )
-                else:
-                    best_path = nbest_decoding(
-                        lattice=lattice,
-                        num_paths=params.num_paths,
-                        use_double_scores=params.use_double_scores,
-                        nbest_scale=params.nbest_scale,
-                    )
-                    key = f"no_rescore-nbest-scale-{params.nbest_scale}-{params.num_paths}"  # noqa
-                    hyps = get_texts(best_path)
-                    hyps = [[word_table[i] for i in ids] for ids in hyps]
-                    timestamps = [[] for _ in range(len(hyps))]
-
-                ans[key + key_suffix] = (hyps, timestamps)
-
-        return ans
-
     lattice = get_lattice(
         nnet_output=nnet_output,
         decoding_graph=decoding_graph,
@@ -532,6 +410,51 @@ def decode_one_batch(
         key = "ctc-decoding"
         return {key: (hyps, timestamps)}
 
+    if params.decoding_method == "nbest-oracle":
+        # Note: You can also pass rescored lattices to it.
+        # We choose the HLG decoded lattice for speed reasons
+        # as HLG decoding is faster and the oracle WER
+        # is only slightly worse than that of rescored lattices.
+        best_path = nbest_oracle(
+            lattice=lattice,
+            num_paths=params.num_paths,
+            ref_texts=supervisions["text"],
+            word_table=word_table,
+            nbest_scale=params.nbest_scale,
+            oov="<UNK>",
+        )
+        hyps = get_texts(best_path)
+        hyps = [[word_table[i] for i in ids] for ids in hyps]
+        timestamps = [[] for _ in range(len(hyps))]
+        key = f"oracle_{params.num_paths}_nbest_scale_{params.nbest_scale}_hlg_scale_{params.hlg_scale}"  # noqa
+        return {key: (hyps, timestamps)}
+
+    if params.decoding_method in ["1best", "nbest"]:
+        if params.decoding_method == "1best":
+            best_path = one_best_decoding(
+                lattice=lattice, use_double_scores=params.use_double_scores
+            )
+            key = f"no_rescore_hlg_scale_{params.hlg_scale}"
+            res = get_texts_with_timestamp(best_path)
+            hyps, timestamps = parse_hyp_and_timestamp(
+                res=res,
+                subsampling_factor=params.subsampling_factor,
+                frame_shift_ms=params.frame_shift_ms,
+                word_table=word_table,
+            )
+        else:
+            best_path = nbest_decoding(
+                lattice=lattice,
+                num_paths=params.num_paths,
+                use_double_scores=params.use_double_scores,
+                nbest_scale=params.nbest_scale,
+            )
+            key = f"no_rescore-nbest-scale-{params.nbest_scale}-{params.num_paths}-hlg-scale-{params.hlg_scale}"  # noqa
+            hyps = get_texts(best_path)
+            hyps = [[word_table[i] for i in ids] for ids in hyps]
+            timestamps = [[] for _ in range(len(hyps))]
+        return {key: (hyps, timestamps)}
+
     assert params.decoding_method in [
         "nbest-rescoring",
         "whole-lattice-rescoring",
@@ -757,7 +680,6 @@ def main():
     params.update(vars(args))
 
     assert params.decoding_method in (
-        "ctc-greedy-search",
         "ctc-decoding",
         "1best",
         "nbest",
@@ -811,7 +733,7 @@ def main():
     params.sos_id = sos_id
     params.eos_id = eos_id
 
-    if params.decoding_method in ["ctc-decoding", "ctc-greedy-search"]:
+    if params.decoding_method == "ctc-decoding":
         HLG = None
         H = k2.ctc_topo(
             max_token=max_token_id,
@@ -828,6 +750,7 @@ def main():
         )
         assert HLG.requires_grad is False
 
+        HLG.scores *= params.hlg_scale
         if not hasattr(HLG, "lm_scores"):
             HLG.lm_scores = HLG.scores.clone()
 
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless2/joiner.py b/egs/librispeech/ASR/pruned_transducer_stateless2/joiner.py
index 1954f4724..9f88bd029 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless2/joiner.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless2/joiner.py
@@ -56,8 +56,6 @@ class Joiner(nn.Module):
         """
         if not is_jit_tracing():
             assert encoder_out.ndim == decoder_out.ndim
-            assert encoder_out.ndim in (2, 4)
-            assert encoder_out.shape == decoder_out.shape
 
         if project_input:
             logit = self.encoder_proj(encoder_out) + self.decoder_proj(decoder_out)
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless3/export-onnx.py b/egs/librispeech/ASR/pruned_transducer_stateless3/export-onnx.py
new file mode 100755
index 000000000..ca8be307c
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless3/export-onnx.py
@@ -0,0 +1,497 @@
+#!/usr/bin/env python3
+#
+# Copyright 2023 Xiaomi Corporation (Author: Fangjun Kuang)
+
+"""
+This script exports a transducer model from PyTorch to ONNX.
+
+We use the pre-trained model from
+https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+as an example to show how to use this file.
+
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained-iter-1224000-avg-14.pt"
+
+cd exp
+ln -s pretrained-iter-1224000-avg-14.pt epoch-9999.pt
+popd
+
+2. Export the model to ONNX
+
+./pruned_transducer_stateless3/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 9999 \
+  --avg 1 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files inside $repo/exp:
+
+  - encoder-epoch-9999-avg-1.onnx
+  - decoder-epoch-9999-avg-1.onnx
+  - joiner-epoch-9999-avg-1.onnx
+
+See ./onnx_pretrained.py and ./onnx_check.py for how to
+use the exported ONNX models.
+"""
+
+import argparse
+import logging
+from pathlib import Path
+from typing import Dict, Tuple
+
+import onnx
+import sentencepiece as spm
+import torch
+import torch.nn as nn
+from conformer import Conformer
+from decoder import Decoder
+from scaling_converter import convert_scaled_to_non_scaled
+from train import add_model_arguments, get_params, get_transducer_model
+
+from icefall.checkpoint import average_checkpoints, find_checkpoints, load_checkpoint
+from icefall.utils import setup_logger
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--epoch",
+        type=int,
+        default=28,
+        help="""It specifies the checkpoint to use for averaging.
+        Note: Epoch counts from 0.
+        You can specify --avg to use more checkpoints for model averaging.""",
+    )
+
+    parser.add_argument(
+        "--iter",
+        type=int,
+        default=0,
+        help="""If positive, --epoch is ignored and it
+        will use the checkpoint exp_dir/checkpoint-iter.pt.
+        You can specify --avg to use more checkpoints for model averaging.
+        """,
+    )
+
+    parser.add_argument(
+        "--avg",
+        type=int,
+        default=15,
+        help="Number of checkpoints to average. Automatically select "
+        "consecutive checkpoints before the checkpoint specified by "
+        "'--epoch' and '--iter'",
+    )
+
+    parser.add_argument(
+        "--exp-dir",
+        type=str,
+        default="pruned_transducer_stateless3/exp",
+        help="""It specifies the directory where all training related
+        files, e.g., checkpoints, log, etc, are saved
+        """,
+    )
+
+    parser.add_argument(
+        "--bpe-model",
+        type=str,
+        default="data/lang_bpe_500/bpe.model",
+        help="Path to the BPE model",
+    )
+
+    parser.add_argument(
+        "--context-size",
+        type=int,
+        default=2,
+        help="The context size in the decoder. 1 means bigram; 2 means tri-gram",
+    )
+
+    add_model_arguments(parser)
+
+    return parser
+
+
+def add_meta_data(filename: str, meta_data: Dict[str, str]):
+    """Add meta data to an ONNX model. It is changed in-place.
+
+    Args:
+      filename:
+        Filename of the ONNX model to be changed.
+      meta_data:
+        Key-value pairs.
+    """
+    model = onnx.load(filename)
+    for key, value in meta_data.items():
+        meta = model.metadata_props.add()
+        meta.key = key
+        meta.value = value
+
+    onnx.save(model, filename)
+
+
+class OnnxEncoder(nn.Module):
+    """A wrapper for Conformer and the encoder_proj from the joiner"""
+
+    def __init__(self, encoder: Conformer, encoder_proj: nn.Linear):
+        """
+        Args:
+          encoder:
+            A Conformer encoder.
+          encoder_proj:
+            The projection layer for encoder from the joiner.
+        """
+        super().__init__()
+        self.encoder = encoder
+        self.encoder_proj = encoder_proj
+
+    def forward(
+        self,
+        x: torch.Tensor,
+        x_lens: torch.Tensor,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """Please see the help information of Conformer.forward
+
+        Args:
+          x:
+            A 3-D tensor of shape (N, T, C)
+          x_lens:
+            A 1-D tensor of shape (N,). Its dtype is torch.int64
+        Returns:
+          Return a tuple containing:
+            - encoder_out, A 3-D tensor of shape (N, T', joiner_dim)
+            - encoder_out_lens, A 1-D tensor of shape (N,)
+        """
+        encoder_out, encoder_out_lens = self.encoder(x, x_lens)
+
+        encoder_out = self.encoder_proj(encoder_out)
+        # Now encoder_out is of shape (N, T, joiner_dim)
+
+        return encoder_out, encoder_out_lens
+
+
+class OnnxDecoder(nn.Module):
+    """A wrapper for Decoder and the decoder_proj from the joiner"""
+
+    def __init__(self, decoder: Decoder, decoder_proj: nn.Linear):
+        super().__init__()
+        self.decoder = decoder
+        self.decoder_proj = decoder_proj
+
+    def forward(self, y: torch.Tensor) -> torch.Tensor:
+        """
+        Args:
+          y:
+            A 2-D tensor of shape (N, context_size).
+        Returns
+          Return a 2-D tensor of shape (N, joiner_dim)
+        """
+        need_pad = False
+        decoder_output = self.decoder(y, need_pad=need_pad)
+        decoder_output = decoder_output.squeeze(1)
+        output = self.decoder_proj(decoder_output)
+
+        return output
+
+
+class OnnxJoiner(nn.Module):
+    """A wrapper for the joiner"""
+
+    def __init__(self, output_linear: nn.Linear):
+        super().__init__()
+        self.output_linear = output_linear
+
+    def forward(
+        self,
+        encoder_out: torch.Tensor,
+        decoder_out: torch.Tensor,
+    ) -> torch.Tensor:
+        """
+        Args:
+          encoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+          decoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+        Returns:
+          Return a 2-D tensor of shape (N, vocab_size)
+        """
+        logit = encoder_out + decoder_out
+        logit = self.output_linear(torch.tanh(logit))
+        return logit
+
+
+def export_encoder_model_onnx(
+    encoder_model: OnnxEncoder,
+    encoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the given encoder model to ONNX format.
+    The exported model has two inputs:
+
+        - x, a tensor of shape (N, T, C); dtype is torch.float32
+        - x_lens, a tensor of shape (N,); dtype is torch.int64
+
+    and it has two outputs:
+
+        - encoder_out, a tensor of shape (N, T', joiner_dim)
+        - encoder_out_lens, a tensor of shape (N,)
+
+    Args:
+      encoder_model:
+        The input encoder model
+      encoder_filename:
+        The filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    x = torch.zeros(1, 100, 80, dtype=torch.float32)
+    x_lens = torch.tensor([100], dtype=torch.int64)
+
+    torch.onnx.export(
+        encoder_model,
+        (x, x_lens),
+        encoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x", "x_lens"],
+        output_names=["encoder_out", "encoder_out_lens"],
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "x_lens": {0: "N"},
+            "encoder_out": {0: "N", 1: "T"},
+            "encoder_out_lens": {0: "N"},
+        },
+    )
+
+
+def export_decoder_model_onnx(
+    decoder_model: OnnxDecoder,
+    decoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the decoder model to ONNX format.
+
+    The exported model has one input:
+
+        - y: a torch.int64 tensor of shape (N, decoder_model.context_size)
+
+    and has one output:
+
+        - decoder_out: a torch.float32 tensor of shape (N, joiner_dim)
+
+    Args:
+      decoder_model:
+        The decoder model to be exported.
+      decoder_filename:
+        Filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    context_size = decoder_model.decoder.context_size
+    vocab_size = decoder_model.decoder.vocab_size
+
+    y = torch.zeros(10, context_size, dtype=torch.int64)
+    torch.onnx.export(
+        decoder_model,
+        y,
+        decoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["y"],
+        output_names=["decoder_out"],
+        dynamic_axes={
+            "y": {0: "N"},
+            "decoder_out": {0: "N"},
+        },
+    )
+
+    meta_data = {
+        "context_size": str(context_size),
+        "vocab_size": str(vocab_size),
+    }
+    add_meta_data(filename=decoder_filename, meta_data=meta_data)
+
+
+def export_joiner_model_onnx(
+    joiner_model: nn.Module,
+    joiner_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the joiner model to ONNX format.
+    The exported joiner model has two inputs:
+
+        - encoder_out: a tensor of shape (N, joiner_dim)
+        - decoder_out: a tensor of shape (N, joiner_dim)
+
+    and produces one output:
+
+        - logit: a tensor of shape (N, vocab_size)
+    """
+    joiner_dim = joiner_model.output_linear.weight.shape[1]
+    logging.info(f"joiner dim: {joiner_dim}")
+
+    projected_encoder_out = torch.rand(11, joiner_dim, dtype=torch.float32)
+    projected_decoder_out = torch.rand(11, joiner_dim, dtype=torch.float32)
+
+    torch.onnx.export(
+        joiner_model,
+        (projected_encoder_out, projected_decoder_out),
+        joiner_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=[
+            "encoder_out",
+            "decoder_out",
+        ],
+        output_names=["logit"],
+        dynamic_axes={
+            "encoder_out": {0: "N"},
+            "decoder_out": {0: "N"},
+            "logit": {0: "N"},
+        },
+    )
+    meta_data = {
+        "joiner_dim": str(joiner_dim),
+    }
+    add_meta_data(filename=joiner_filename, meta_data=meta_data)
+
+
+@torch.no_grad()
+def main():
+    args = get_parser().parse_args()
+    args.exp_dir = Path(args.exp_dir)
+
+    params = get_params()
+    params.update(vars(args))
+
+    device = torch.device("cpu")
+    if torch.cuda.is_available():
+        device = torch.device("cuda", 0)
+
+    setup_logger(f"{params.exp_dir}/log-export/log-export-onnx")
+
+    logging.info(f"device: {device}")
+
+    sp = spm.SentencePieceProcessor()
+    sp.load(params.bpe_model)
+
+    # <blk> is defined in local/train_bpe_model.py
+    params.blank_id = sp.piece_to_id("<blk>")
+    params.vocab_size = sp.get_piece_size()
+
+    logging.info(params)
+
+    logging.info("About to create model")
+    model = get_transducer_model(params, enable_giga=False)
+
+    model.to(device)
+
+    if params.iter > 0:
+        filenames = find_checkpoints(params.exp_dir, iteration=-params.iter)[
+            : params.avg
+        ]
+        if len(filenames) == 0:
+            raise ValueError(
+                f"No checkpoints found for --iter {params.iter}, --avg {params.avg}"
+            )
+        elif len(filenames) < params.avg:
+            raise ValueError(
+                f"Not enough checkpoints ({len(filenames)}) found for"
+                f" --iter {params.iter}, --avg {params.avg}"
+            )
+        logging.info(f"averaging {filenames}")
+        model.to(device)
+        model.load_state_dict(
+            average_checkpoints(filenames, device=device), strict=False
+        )
+    elif params.avg == 1:
+        load_checkpoint(f"{params.exp_dir}/epoch-{params.epoch}.pt", model)
+    else:
+        start = params.epoch - params.avg + 1
+        filenames = []
+        for i in range(start, params.epoch + 1):
+            if start >= 0:
+                filenames.append(f"{params.exp_dir}/epoch-{i}.pt")
+        logging.info(f"averaging {filenames}")
+        model.to(device)
+        model.load_state_dict(
+            average_checkpoints(filenames, device=device), strict=False
+        )
+
+    model.to("cpu")
+    model.eval()
+
+    convert_scaled_to_non_scaled(model, inplace=True)
+
+    encoder = OnnxEncoder(
+        encoder=model.encoder,
+        encoder_proj=model.joiner.encoder_proj,
+    )
+
+    decoder = OnnxDecoder(
+        decoder=model.decoder,
+        decoder_proj=model.joiner.decoder_proj,
+    )
+
+    joiner = OnnxJoiner(output_linear=model.joiner.output_linear)
+
+    encoder_num_param = sum([p.numel() for p in encoder.parameters()])
+    decoder_num_param = sum([p.numel() for p in decoder.parameters()])
+    joiner_num_param = sum([p.numel() for p in joiner.parameters()])
+    total_num_param = encoder_num_param + decoder_num_param + joiner_num_param
+    logging.info(f"encoder parameters: {encoder_num_param}")
+    logging.info(f"decoder parameters: {decoder_num_param}")
+    logging.info(f"joiner parameters: {joiner_num_param}")
+    logging.info(f"total parameters: {total_num_param}")
+
+    if params.iter > 0:
+        suffix = f"iter-{params.iter}"
+    else:
+        suffix = f"epoch-{params.epoch}"
+
+    suffix += f"-avg-{params.avg}"
+
+    opset_version = 13
+
+    logging.info("Exporting encoder")
+    encoder_filename = params.exp_dir / f"encoder-{suffix}.onnx"
+    export_encoder_model_onnx(
+        encoder,
+        encoder_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported encoder to {encoder_filename}")
+
+    logging.info("Exporting decoder")
+    decoder_filename = params.exp_dir / f"decoder-{suffix}.onnx"
+    export_decoder_model_onnx(
+        decoder,
+        decoder_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported decoder to {decoder_filename}")
+
+    logging.info("Exporting joiner")
+    joiner_filename = params.exp_dir / f"joiner-{suffix}.onnx"
+    export_joiner_model_onnx(
+        joiner,
+        joiner_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported joiner to {joiner_filename}")
+
+
+if __name__ == "__main__":
+    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
+
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless3/export.py b/egs/librispeech/ASR/pruned_transducer_stateless3/export.py
index 239bdc12f..f30c9df6a 100755
--- a/egs/librispeech/ASR/pruned_transducer_stateless3/export.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless3/export.py
@@ -52,32 +52,7 @@ It will also generate 3 other files: `encoder_jit_script.pt`,
 It will generates 3 files: `encoder_jit_trace.pt`,
 `decoder_jit_trace.pt`, and `joiner_jit_trace.pt`.
 
-
-(3) Export to ONNX format
-
-./pruned_transducer_stateless3/export.py \
-  --exp-dir ./pruned_transducer_stateless3/exp \
-  --bpe-model data/lang_bpe_500/bpe.model \
-  --epoch 20 \
-  --avg 10 \
-  --onnx 1
-
-It will generate the following files in the given `exp_dir`.
-Check `onnx_check.py` for how to use them.
-
-    - encoder.onnx
-    - decoder.onnx
-    - joiner.onnx
-    - joiner_encoder_proj.onnx
-    - joiner_decoder_proj.onnx
-
-Please see ./onnx_pretrained.py for usage of the generated files
-
-Check
-https://github.com/k2-fsa/sherpa-onnx
-for how to use the exported models outside of icefall.
-
-(4) Export `model.state_dict()`
+(3) Export `model.state_dict()`
 
 ./pruned_transducer_stateless3/export.py \
   --exp-dir ./pruned_transducer_stateless3/exp \
@@ -210,23 +185,6 @@ def get_parser():
         """,
     )
 
-    parser.add_argument(
-        "--onnx",
-        type=str2bool,
-        default=False,
-        help="""If True, --jit is ignored and it exports the model
-        to onnx format. It will generate the following files:
-
-            - encoder.onnx
-            - decoder.onnx
-            - joiner.onnx
-            - joiner_encoder_proj.onnx
-            - joiner_decoder_proj.onnx
-
-        Refer to ./onnx_check.py and ./onnx_pretrained.py for how to use them.
-        """,
-    )
-
     parser.add_argument(
         "--context-size",
         type=int,
@@ -370,206 +328,6 @@ def export_joiner_model_jit_trace(
     logging.info(f"Saved to {joiner_filename}")
 
 
-def export_encoder_model_onnx(
-    encoder_model: nn.Module,
-    encoder_filename: str,
-    opset_version: int = 11,
-) -> None:
-    """Export the given encoder model to ONNX format.
-    The exported model has two inputs:
-
-        - x, a tensor of shape (N, T, C); dtype is torch.float32
-        - x_lens, a tensor of shape (N,); dtype is torch.int64
-
-    and it has two outputs:
-
-        - encoder_out, a tensor of shape (N, T, C)
-        - encoder_out_lens, a tensor of shape (N,)
-
-    Note: The warmup argument is fixed to 1.
-
-    Args:
-      encoder_model:
-        The input encoder model
-      encoder_filename:
-        The filename to save the exported ONNX model.
-      opset_version:
-        The opset version to use.
-    """
-    x = torch.zeros(1, 100, 80, dtype=torch.float32)
-    x_lens = torch.tensor([100], dtype=torch.int64)
-
-    #  encoder_model = torch.jit.script(encoder_model)
-    # It throws the following error for the above statement
-    #
-    # RuntimeError: Exporting the operator __is_ to ONNX opset version
-    # 11 is not supported. Please feel free to request support or
-    # submit a pull request on PyTorch GitHub.
-    #
-    # I cannot find which statement causes the above error.
-    # torch.onnx.export() will use torch.jit.trace() internally, which
-    # works well for the current reworked model
-    warmup = 1.0
-    torch.onnx.export(
-        encoder_model,
-        (x, x_lens, warmup),
-        encoder_filename,
-        verbose=False,
-        opset_version=opset_version,
-        input_names=["x", "x_lens", "warmup"],
-        output_names=["encoder_out", "encoder_out_lens"],
-        dynamic_axes={
-            "x": {0: "N", 1: "T"},
-            "x_lens": {0: "N"},
-            "encoder_out": {0: "N", 1: "T"},
-            "encoder_out_lens": {0: "N"},
-        },
-    )
-    logging.info(f"Saved to {encoder_filename}")
-
-
-def export_decoder_model_onnx(
-    decoder_model: nn.Module,
-    decoder_filename: str,
-    opset_version: int = 11,
-) -> None:
-    """Export the decoder model to ONNX format.
-
-    The exported model has one input:
-
-        - y: a torch.int64 tensor of shape (N, decoder_model.context_size)
-
-    and has one output:
-
-        - decoder_out: a torch.float32 tensor of shape (N, 1, C)
-
-    Note: The argument need_pad is fixed to False.
-
-    Args:
-      decoder_model:
-        The decoder model to be exported.
-      decoder_filename:
-        Filename to save the exported ONNX model.
-      opset_version:
-        The opset version to use.
-    """
-    y = torch.zeros(10, decoder_model.context_size, dtype=torch.int64)
-    need_pad = False  # Always False, so we can use torch.jit.trace() here
-    # Note(fangjun): torch.jit.trace() is more efficient than torch.jit.script()
-    # in this case
-    torch.onnx.export(
-        decoder_model,
-        (y, need_pad),
-        decoder_filename,
-        verbose=False,
-        opset_version=opset_version,
-        input_names=["y", "need_pad"],
-        output_names=["decoder_out"],
-        dynamic_axes={
-            "y": {0: "N"},
-            "decoder_out": {0: "N"},
-        },
-    )
-    logging.info(f"Saved to {decoder_filename}")
-
-
-def export_joiner_model_onnx(
-    joiner_model: nn.Module,
-    joiner_filename: str,
-    opset_version: int = 11,
-) -> None:
-    """Export the joiner model to ONNX format.
-    The exported joiner model has two inputs:
-
-        - projected_encoder_out: a tensor of shape (N, joiner_dim)
-        - projected_decoder_out: a tensor of shape (N, joiner_dim)
-
-    and produces one output:
-
-        - logit: a tensor of shape (N, vocab_size)
-
-    The exported encoder_proj model has one input:
-
-        - encoder_out: a tensor of shape (N, encoder_out_dim)
-
-    and produces one output:
-
-        - projected_encoder_out: a tensor of shape (N, joiner_dim)
-
-    The exported decoder_proj model has one input:
-
-        - decoder_out: a tensor of shape (N, decoder_out_dim)
-
-    and produces one output:
-
-        - projected_decoder_out: a tensor of shape (N, joiner_dim)
-    """
-    encoder_proj_filename = str(joiner_filename).replace(".onnx", "_encoder_proj.onnx")
-
-    decoder_proj_filename = str(joiner_filename).replace(".onnx", "_decoder_proj.onnx")
-
-    encoder_out_dim = joiner_model.encoder_proj.weight.shape[1]
-    decoder_out_dim = joiner_model.decoder_proj.weight.shape[1]
-    joiner_dim = joiner_model.decoder_proj.weight.shape[0]
-
-    projected_encoder_out = torch.rand(1, joiner_dim, dtype=torch.float32)
-    projected_decoder_out = torch.rand(1, joiner_dim, dtype=torch.float32)
-
-    project_input = False
-    # Note: It uses torch.jit.trace() internally
-    torch.onnx.export(
-        joiner_model,
-        (projected_encoder_out, projected_decoder_out, project_input),
-        joiner_filename,
-        verbose=False,
-        opset_version=opset_version,
-        input_names=[
-            "projected_encoder_out",
-            "projected_decoder_out",
-            "project_input",
-        ],
-        output_names=["logit"],
-        dynamic_axes={
-            "projected_encoder_out": {0: "N"},
-            "projected_decoder_out": {0: "N"},
-            "logit": {0: "N"},
-        },
-    )
-    logging.info(f"Saved to {joiner_filename}")
-
-    encoder_out = torch.rand(1, encoder_out_dim, dtype=torch.float32)
-    torch.onnx.export(
-        joiner_model.encoder_proj,
-        encoder_out,
-        encoder_proj_filename,
-        verbose=False,
-        opset_version=opset_version,
-        input_names=["encoder_out"],
-        output_names=["projected_encoder_out"],
-        dynamic_axes={
-            "encoder_out": {0: "N"},
-            "projected_encoder_out": {0: "N"},
-        },
-    )
-    logging.info(f"Saved to {encoder_proj_filename}")
-
-    decoder_out = torch.rand(1, decoder_out_dim, dtype=torch.float32)
-    torch.onnx.export(
-        joiner_model.decoder_proj,
-        decoder_out,
-        decoder_proj_filename,
-        verbose=False,
-        opset_version=opset_version,
-        input_names=["decoder_out"],
-        output_names=["projected_decoder_out"],
-        dynamic_axes={
-            "decoder_out": {0: "N"},
-            "projected_decoder_out": {0: "N"},
-        },
-    )
-    logging.info(f"Saved to {decoder_proj_filename}")
-
-
 @torch.no_grad()
 def main():
     args = get_parser().parse_args()
@@ -636,31 +394,7 @@ def main():
     model.to("cpu")
     model.eval()
 
-    if params.onnx is True:
-        convert_scaled_to_non_scaled(model, inplace=True)
-        opset_version = 11
-        logging.info("Exporting to onnx format")
-        encoder_filename = params.exp_dir / "encoder.onnx"
-        export_encoder_model_onnx(
-            model.encoder,
-            encoder_filename,
-            opset_version=opset_version,
-        )
-
-        decoder_filename = params.exp_dir / "decoder.onnx"
-        export_decoder_model_onnx(
-            model.decoder,
-            decoder_filename,
-            opset_version=opset_version,
-        )
-
-        joiner_filename = params.exp_dir / "joiner.onnx"
-        export_joiner_model_onnx(
-            model.joiner,
-            joiner_filename,
-            opset_version=opset_version,
-        )
-    elif params.jit is True:
+    if params.jit is True:
         convert_scaled_to_non_scaled(model, inplace=True)
         logging.info("Using torch.jit.script()")
         # We won't use the forward() method of the model in C++, so just ignore
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_check.py b/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_check.py
index 163d737e3..6541f0295 100755
--- a/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_check.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_check.py
@@ -19,21 +19,70 @@
 """
 This script checks that exported onnx models produce the same output
 with the given torchscript model for the same input.
+
+We use the pre-trained model from
+https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+as an example to show how to use this file.
+
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained-iter-1224000-avg-14.pt"
+
+cd exp
+ln -s pretrained-iter-1224000-avg-14.pt epoch-9999.pt
+popd
+
+2. Export the model via torchscript (torch.jit.script())
+
+./pruned_transducer_stateless3/export.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 9999 \
+  --avg 1 \
+  --exp-dir $repo/exp/ \
+  --jit 1
+
+It will generate the following file in $repo/exp:
+    - cpu_jit.pt
+
+3. Export the model to ONNX
+
+./pruned_transducer_stateless3/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 9999 \
+  --avg 1 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files inside $repo/exp:
+
+  - encoder-epoch-9999-avg-1.onnx
+  - decoder-epoch-9999-avg-1.onnx
+  - joiner-epoch-9999-avg-1.onnx
+
+4. Run this file
+
+./pruned_transducer_stateless3/onnx_check.py \
+  --jit-filename $repo/exp/cpu_jit.pt \
+  --onnx-encoder-filename $repo/exp/encoder-epoch-9999-avg-1.onnx \
+  --onnx-decoder-filename $repo/exp/decoder-epoch-9999-avg-1.onnx \
+  --onnx-joiner-filename $repo/exp/joiner-epoch-9999-avg-1.onnx
 """
 
 import argparse
 import logging
 
 from icefall import is_module_available
+from onnx_pretrained import OnnxModel
 
-if not is_module_available("onnxruntime"):
-    raise ValueError("Please 'pip install onnxruntime' first.")
-
-import onnxruntime as ort
 import torch
 
-ort.set_default_logger_severity(3)
-
 
 def get_parser():
     parser = argparse.ArgumentParser(
@@ -68,163 +117,81 @@ def get_parser():
         help="Path to the onnx joiner model",
     )
 
-    parser.add_argument(
-        "--onnx-joiner-encoder-proj-filename",
-        required=True,
-        type=str,
-        help="Path to the onnx joiner encoder projection model",
-    )
-
-    parser.add_argument(
-        "--onnx-joiner-decoder-proj-filename",
-        required=True,
-        type=str,
-        help="Path to the onnx joiner decoder projection model",
-    )
-
     return parser
 
 
 def test_encoder(
-    model: torch.jit.ScriptModule,
-    encoder_session: ort.InferenceSession,
+    torch_model: torch.jit.ScriptModule,
+    onnx_model: OnnxModel,
 ):
-    inputs = encoder_session.get_inputs()
-    outputs = encoder_session.get_outputs()
-    input_names = [n.name for n in inputs]
-    output_names = [n.name for n in outputs]
+    C = 80
+    for i in range(10):
+        N = torch.randint(low=1, high=20, size=(1,)).item()
+        T = torch.randint(low=50, high=100, size=(1,)).item()
+        logging.info(f"test_encoder: iter {i}, N={N}, T={T}")
 
-    assert inputs[0].shape == ["N", "T", 80]
-    assert inputs[1].shape == ["N"]
+        x = torch.rand(N, T, C)
+        x_lens = torch.randint(low=10, high=T + 1, size=(N,))
+        x_lens[0] = T
 
-    for N in [1, 5]:
-        for T in [12, 25]:
-            print("N, T", N, T)
-            x = torch.rand(N, T, 80, dtype=torch.float32)
-            x_lens = torch.randint(low=10, high=T + 1, size=(N,))
-            x_lens[0] = T
+        torch_encoder_out, torch_encoder_out_lens = torch_model.encoder(x, x_lens)
+        torch_encoder_out = torch_model.joiner.encoder_proj(torch_encoder_out)
 
-            encoder_inputs = {
-                input_names[0]: x.numpy(),
-                input_names[1]: x_lens.numpy(),
-            }
-            encoder_out, encoder_out_lens = encoder_session.run(
-                output_names,
-                encoder_inputs,
-            )
+        onnx_encoder_out, onnx_encoder_out_lens = onnx_model.run_encoder(x, x_lens)
 
-            torch_encoder_out, torch_encoder_out_lens = model.encoder(x, x_lens)
-
-            encoder_out = torch.from_numpy(encoder_out)
-            assert torch.allclose(encoder_out, torch_encoder_out, atol=1e-05), (
-                (encoder_out - torch_encoder_out).abs().max(),
-                encoder_out.shape,
-                torch_encoder_out.shape,
-            )
+        assert torch.allclose(torch_encoder_out, onnx_encoder_out, atol=1e-05), (
+            (torch_encoder_out - onnx_encoder_out).abs().max()
+        )
 
 
 def test_decoder(
-    model: torch.jit.ScriptModule,
-    decoder_session: ort.InferenceSession,
+    torch_model: torch.jit.ScriptModule,
+    onnx_model: OnnxModel,
 ):
-    inputs = decoder_session.get_inputs()
-    outputs = decoder_session.get_outputs()
-    input_names = [n.name for n in inputs]
-    output_names = [n.name for n in outputs]
+    context_size = onnx_model.context_size
+    vocab_size = onnx_model.vocab_size
+    for i in range(10):
+        N = torch.randint(1, 100, size=(1,)).item()
+        logging.info(f"test_decoder: iter {i}, N={N}")
+        x = torch.randint(
+            low=1,
+            high=vocab_size,
+            size=(N, context_size),
+            dtype=torch.int64,
+        )
+        torch_decoder_out = torch_model.decoder(x, need_pad=torch.tensor([False]))
+        torch_decoder_out = torch_model.joiner.decoder_proj(torch_decoder_out)
+        torch_decoder_out = torch_decoder_out.squeeze(1)
 
-    assert inputs[0].shape == ["N", 2]
-    for N in [1, 5, 10]:
-        y = torch.randint(low=1, high=500, size=(10, 2))
-
-        decoder_inputs = {input_names[0]: y.numpy()}
-        decoder_out = decoder_session.run(
-            output_names,
-            decoder_inputs,
-        )[0]
-        decoder_out = torch.from_numpy(decoder_out)
-
-        torch_decoder_out = model.decoder(y, need_pad=False)
-        assert torch.allclose(decoder_out, torch_decoder_out, atol=1e-5), (
-            (decoder_out - torch_decoder_out).abs().max()
+        onnx_decoder_out = onnx_model.run_decoder(x)
+        assert torch.allclose(torch_decoder_out, onnx_decoder_out, atol=1e-4), (
+            (torch_decoder_out - onnx_decoder_out).abs().max()
         )
 
 
 def test_joiner(
-    model: torch.jit.ScriptModule,
-    joiner_session: ort.InferenceSession,
-    joiner_encoder_proj_session: ort.InferenceSession,
-    joiner_decoder_proj_session: ort.InferenceSession,
+    torch_model: torch.jit.ScriptModule,
+    onnx_model: OnnxModel,
 ):
-    joiner_inputs = joiner_session.get_inputs()
-    joiner_outputs = joiner_session.get_outputs()
-    joiner_input_names = [n.name for n in joiner_inputs]
-    joiner_output_names = [n.name for n in joiner_outputs]
+    encoder_dim = torch_model.joiner.encoder_proj.weight.shape[1]
+    decoder_dim = torch_model.joiner.decoder_proj.weight.shape[1]
+    for i in range(10):
+        N = torch.randint(1, 100, size=(1,)).item()
+        logging.info(f"test_joiner: iter {i}, N={N}")
+        encoder_out = torch.rand(N, encoder_dim)
+        decoder_out = torch.rand(N, decoder_dim)
 
-    assert joiner_inputs[0].shape == ["N", 512]
-    assert joiner_inputs[1].shape == ["N", 512]
+        projected_encoder_out = torch_model.joiner.encoder_proj(encoder_out)
+        projected_decoder_out = torch_model.joiner.decoder_proj(decoder_out)
 
-    joiner_encoder_proj_inputs = joiner_encoder_proj_session.get_inputs()
-    encoder_proj_input_name = joiner_encoder_proj_inputs[0].name
-
-    assert joiner_encoder_proj_inputs[0].shape == ["N", 512]
-
-    joiner_encoder_proj_outputs = joiner_encoder_proj_session.get_outputs()
-    encoder_proj_output_name = joiner_encoder_proj_outputs[0].name
-
-    joiner_decoder_proj_inputs = joiner_decoder_proj_session.get_inputs()
-    decoder_proj_input_name = joiner_decoder_proj_inputs[0].name
-
-    assert joiner_decoder_proj_inputs[0].shape == ["N", 512]
-
-    joiner_decoder_proj_outputs = joiner_decoder_proj_session.get_outputs()
-    decoder_proj_output_name = joiner_decoder_proj_outputs[0].name
-
-    for N in [1, 5, 10]:
-        encoder_out = torch.rand(N, 512)
-        decoder_out = torch.rand(N, 512)
-
-        projected_encoder_out = torch.rand(N, 512)
-        projected_decoder_out = torch.rand(N, 512)
-
-        joiner_inputs = {
-            joiner_input_names[0]: projected_encoder_out.numpy(),
-            joiner_input_names[1]: projected_decoder_out.numpy(),
-        }
-        joiner_out = joiner_session.run(joiner_output_names, joiner_inputs)[0]
-        joiner_out = torch.from_numpy(joiner_out)
-
-        torch_joiner_out = model.joiner(
-            projected_encoder_out,
-            projected_decoder_out,
-            project_input=False,
-        )
-        assert torch.allclose(joiner_out, torch_joiner_out, atol=1e-5), (
-            (joiner_out - torch_joiner_out).abs().max()
+        torch_joiner_out = torch_model.joiner(encoder_out, decoder_out)
+        onnx_joiner_out = onnx_model.run_joiner(
+            projected_encoder_out, projected_decoder_out
         )
 
-        # Now test encoder_proj
-        joiner_encoder_proj_inputs = {encoder_proj_input_name: encoder_out.numpy()}
-        joiner_encoder_proj_out = joiner_encoder_proj_session.run(
-            [encoder_proj_output_name], joiner_encoder_proj_inputs
-        )[0]
-        joiner_encoder_proj_out = torch.from_numpy(joiner_encoder_proj_out)
-
-        torch_joiner_encoder_proj_out = model.joiner.encoder_proj(encoder_out)
-        assert torch.allclose(
-            joiner_encoder_proj_out, torch_joiner_encoder_proj_out, atol=1e-5
-        ), ((joiner_encoder_proj_out - torch_joiner_encoder_proj_out).abs().max())
-
-        # Now test decoder_proj
-        joiner_decoder_proj_inputs = {decoder_proj_input_name: decoder_out.numpy()}
-        joiner_decoder_proj_out = joiner_decoder_proj_session.run(
-            [decoder_proj_output_name], joiner_decoder_proj_inputs
-        )[0]
-        joiner_decoder_proj_out = torch.from_numpy(joiner_decoder_proj_out)
-
-        torch_joiner_decoder_proj_out = model.joiner.decoder_proj(decoder_out)
-        assert torch.allclose(
-            joiner_decoder_proj_out, torch_joiner_decoder_proj_out, atol=1e-5
-        ), ((joiner_decoder_proj_out - torch_joiner_decoder_proj_out).abs().max())
+        assert torch.allclose(torch_joiner_out, onnx_joiner_out, atol=1e-4), (
+            (torch_joiner_out - onnx_joiner_out).abs().max()
+        )
 
 
 @torch.no_grad()
@@ -232,48 +199,38 @@ def main():
     args = get_parser().parse_args()
     logging.info(vars(args))
 
-    model = torch.jit.load(args.jit_filename)
+    torch_model = torch.jit.load(args.jit_filename)
 
-    options = ort.SessionOptions()
-    options.inter_op_num_threads = 1
-    options.intra_op_num_threads = 1
+    onnx_model = OnnxModel(
+        encoder_model_filename=args.onnx_encoder_filename,
+        decoder_model_filename=args.onnx_decoder_filename,
+        joiner_model_filename=args.onnx_joiner_filename,
+    )
 
     logging.info("Test encoder")
-    encoder_session = ort.InferenceSession(
-        args.onnx_encoder_filename,
-        sess_options=options,
-    )
-    test_encoder(model, encoder_session)
+    test_encoder(torch_model, onnx_model)
 
     logging.info("Test decoder")
-    decoder_session = ort.InferenceSession(
-        args.onnx_decoder_filename,
-        sess_options=options,
-    )
-    test_decoder(model, decoder_session)
+    test_decoder(torch_model, onnx_model)
 
     logging.info("Test joiner")
-    joiner_session = ort.InferenceSession(
-        args.onnx_joiner_filename,
-        sess_options=options,
-    )
-    joiner_encoder_proj_session = ort.InferenceSession(
-        args.onnx_joiner_encoder_proj_filename,
-        sess_options=options,
-    )
-    joiner_decoder_proj_session = ort.InferenceSession(
-        args.onnx_joiner_decoder_proj_filename,
-        sess_options=options,
-    )
-    test_joiner(
-        model,
-        joiner_session,
-        joiner_encoder_proj_session,
-        joiner_decoder_proj_session,
-    )
+    test_joiner(torch_model, onnx_model)
     logging.info("Finished checking ONNX models")
 
 
+torch.set_num_threads(1)
+torch.set_num_interop_threads(1)
+
+# See https://github.com/pytorch/pytorch/issues/38342
+# and https://github.com/pytorch/pytorch/issues/33354
+#
+# If we don't do this, the delay increases whenever there is
+# a new request that changes the actual batch size.
+# If you use `py-spy dump --pid <server-pid> --native`, you will
+# see a lot of time is spent in re-compiling the torch script model.
+torch._C._jit_set_profiling_executor(False)
+torch._C._jit_set_profiling_mode(False)
+torch._C._set_graph_executor_optimize(False)
 if __name__ == "__main__":
     torch.manual_seed(20220727)
     formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_pretrained.py b/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_pretrained.py
index 550cf6aad..5adb6c16a 100755
--- a/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_pretrained.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless3/onnx_pretrained.py
@@ -18,35 +18,61 @@
 This script loads ONNX models and uses them to decode waves.
 You can use the following command to get the exported models:
 
-./pruned_transducer_stateless3/export.py \
-  --exp-dir ./pruned_transducer_stateless3/exp \
-  --bpe-model data/lang_bpe_500/bpe.model \
-  --epoch 20 \
-  --avg 10 \
-  --onnx 1
+We use the pre-trained model from
+https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+as an example to show how to use this file.
 
-Usage of this script:
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained-iter-1224000-avg-14.pt"
+
+cd exp
+ln -s pretrained-iter-1224000-avg-14.pt epoch-9999.pt
+popd
+
+2. Export the model to ONNX
+
+./pruned_transducer_stateless3/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 9999 \
+  --avg 1 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files inside $repo/exp:
+
+  - encoder-epoch-9999-avg-1.onnx
+  - decoder-epoch-9999-avg-1.onnx
+  - joiner-epoch-9999-avg-1.onnx
+
+3. Run this file
 
 ./pruned_transducer_stateless3/onnx_pretrained.py \
-  --encoder-model-filename ./pruned_transducer_stateless3/exp/encoder.onnx \
-  --decoder-model-filename ./pruned_transducer_stateless3/exp/decoder.onnx \
-  --joiner-model-filename ./pruned_transducer_stateless3/exp/joiner.onnx \
-  --joiner-encoder-proj-model-filename ./pruned_transducer_stateless3/exp/joiner_encoder_proj.onnx \
-  --joiner-decoder-proj-model-filename ./pruned_transducer_stateless3/exp/joiner_decoder_proj.onnx \
-  --bpe-model ./data/lang_bpe_500/bpe.model \
-  /path/to/foo.wav \
-  /path/to/bar.wav
+  --encoder-model-filename $repo/exp/encoder-epoch-9999-avg-1.onnx \
+  --decoder-model-filename $repo/exp/decoder-epoch-9999-avg-1.onnx \
+  --joiner-model-filename $repo/exp/joiner-epoch-9999-avg-1.onnx \
+  --tokens $repo/data/lang_bpe_500/tokens.txt \
+  $repo/test_wavs/1089-134686-0001.wav \
+  $repo/test_wavs/1221-135766-0001.wav \
+  $repo/test_wavs/1221-135766-0002.wav
 """
 
 import argparse
 import logging
 import math
-from typing import List
+from typing import List, Tuple
 
+import k2
 import kaldifeat
 import numpy as np
 import onnxruntime as ort
-import sentencepiece as spm
 import torch
 import torchaudio
 from torch.nn.utils.rnn import pad_sequence
@@ -79,23 +105,9 @@ def get_parser():
     )
 
     parser.add_argument(
-        "--joiner-encoder-proj-model-filename",
+        "--tokens",
         type=str,
-        required=True,
-        help="Path to the joiner encoder_proj onnx model. ",
-    )
-
-    parser.add_argument(
-        "--joiner-decoder-proj-model-filename",
-        type=str,
-        required=True,
-        help="Path to the joiner decoder_proj onnx model. ",
-    )
-
-    parser.add_argument(
-        "--bpe-model",
-        type=str,
-        help="""Path to bpe.model.""",
+        help="""Path to tokens.txt.""",
     )
 
     parser.add_argument(
@@ -115,16 +127,122 @@ def get_parser():
         help="The sample rate of the input sound file",
     )
 
-    parser.add_argument(
-        "--context-size",
-        type=int,
-        default=2,
-        help="Context size of the decoder model",
-    )
-
     return parser
 
 
+class OnnxModel:
+    def __init__(
+        self,
+        encoder_model_filename: str,
+        decoder_model_filename: str,
+        joiner_model_filename: str,
+    ):
+        session_opts = ort.SessionOptions()
+        session_opts.inter_op_num_threads = 1
+        session_opts.intra_op_num_threads = 1
+
+        self.session_opts = session_opts
+
+        self.init_encoder(encoder_model_filename)
+        self.init_decoder(decoder_model_filename)
+        self.init_joiner(joiner_model_filename)
+
+    def init_encoder(self, encoder_model_filename: str):
+        self.encoder = ort.InferenceSession(
+            encoder_model_filename,
+            sess_options=self.session_opts,
+        )
+
+    def init_decoder(self, decoder_model_filename: str):
+        self.decoder = ort.InferenceSession(
+            decoder_model_filename,
+            sess_options=self.session_opts,
+        )
+
+        decoder_meta = self.decoder.get_modelmeta().custom_metadata_map
+        self.context_size = int(decoder_meta["context_size"])
+        self.vocab_size = int(decoder_meta["vocab_size"])
+
+        logging.info(f"context_size: {self.context_size}")
+        logging.info(f"vocab_size: {self.vocab_size}")
+
+    def init_joiner(self, joiner_model_filename: str):
+        self.joiner = ort.InferenceSession(
+            joiner_model_filename,
+            sess_options=self.session_opts,
+        )
+
+        joiner_meta = self.joiner.get_modelmeta().custom_metadata_map
+        self.joiner_dim = int(joiner_meta["joiner_dim"])
+
+        logging.info(f"joiner_dim: {self.joiner_dim}")
+
+    def run_encoder(
+        self,
+        x: torch.Tensor,
+        x_lens: torch.Tensor,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """
+        Args:
+          x:
+            A 3-D tensor of shape (N, T, C)
+          x_lens:
+            A 2-D tensor of shape (N,). Its dtype is torch.int64
+        Returns:
+          Return a tuple containing:
+            - encoder_out, its shape is (N, T', joiner_dim)
+            - encoder_out_lens, its shape is (N,)
+        """
+        out = self.encoder.run(
+            [
+                self.encoder.get_outputs()[0].name,
+                self.encoder.get_outputs()[1].name,
+            ],
+            {
+                self.encoder.get_inputs()[0].name: x.numpy(),
+                self.encoder.get_inputs()[1].name: x_lens.numpy(),
+            },
+        )
+        return torch.from_numpy(out[0]), torch.from_numpy(out[1])
+
+    def run_decoder(self, decoder_input: torch.Tensor) -> torch.Tensor:
+        """
+        Args:
+          decoder_input:
+            A 2-D tensor of shape (N, context_size)
+        Returns:
+          Return a 2-D tensor of shape (N, joiner_dim)
+        """
+        out = self.decoder.run(
+            [self.decoder.get_outputs()[0].name],
+            {self.decoder.get_inputs()[0].name: decoder_input.numpy()},
+        )[0]
+
+        return torch.from_numpy(out)
+
+    def run_joiner(
+        self, encoder_out: torch.Tensor, decoder_out: torch.Tensor
+    ) -> torch.Tensor:
+        """
+        Args:
+          encoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+          decoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+        Returns:
+          Return a 2-D tensor of shape (N, vocab_size)
+        """
+        out = self.joiner.run(
+            [self.joiner.get_outputs()[0].name],
+            {
+                self.joiner.get_inputs()[0].name: encoder_out.numpy(),
+                self.joiner.get_inputs()[1].name: decoder_out.numpy(),
+            },
+        )[0]
+
+        return torch.from_numpy(out)
+
+
 def read_sound_files(
     filenames: List[str], expected_sample_rate: float
 ) -> List[torch.Tensor]:
@@ -149,36 +267,22 @@ def read_sound_files(
 
 
 def greedy_search(
-    decoder: ort.InferenceSession,
-    joiner: ort.InferenceSession,
-    joiner_encoder_proj: ort.InferenceSession,
-    joiner_decoder_proj: ort.InferenceSession,
-    encoder_out: np.ndarray,
-    encoder_out_lens: np.ndarray,
-    context_size: int,
+    model: OnnxModel,
+    encoder_out: torch.Tensor,
+    encoder_out_lens: torch.Tensor,
 ) -> List[List[int]]:
     """Greedy search in batch mode. It hardcodes --max-sym-per-frame=1.
     Args:
-      decoder:
-        The decoder model.
-      joiner:
-        The joiner model.
-      joiner_encoder_proj:
-        The joiner encoder projection model.
-      joiner_decoder_proj:
-        The joiner decoder projection model.
+      model:
+        The transducer model.
       encoder_out:
-        A 3-D tensor of shape (N, T, C)
+        A 3-D tensor of shape (N, T, joiner_dim)
       encoder_out_lens:
         A 1-D tensor of shape (N,).
-      context_size:
-        The context size of the decoder model.
     Returns:
       Return the decoded results for each utterance.
     """
-    encoder_out = torch.from_numpy(encoder_out)
-    encoder_out_lens = torch.from_numpy(encoder_out_lens)
-    assert encoder_out.ndim == 3
+    assert encoder_out.ndim == 3, encoder_out.shape
     assert encoder_out.size(0) >= 1, encoder_out.size(0)
 
     packed_encoder_out = torch.nn.utils.rnn.pack_padded_sequence(
@@ -188,11 +292,6 @@ def greedy_search(
         enforce_sorted=False,
     )
 
-    projected_encoder_out = joiner_encoder_proj.run(
-        [joiner_encoder_proj.get_outputs()[0].name],
-        {joiner_encoder_proj.get_inputs()[0].name: packed_encoder_out.data.numpy()},
-    )[0]
-
     blank_id = 0  # hard-code to 0
 
     batch_size_list = packed_encoder_out.batch_sizes.tolist()
@@ -201,50 +300,27 @@ def greedy_search(
     assert torch.all(encoder_out_lens > 0), encoder_out_lens
     assert N == batch_size_list[0], (N, batch_size_list)
 
+    context_size = model.context_size
     hyps = [[blank_id] * context_size for _ in range(N)]
 
-    decoder_input_nodes = decoder.get_inputs()
-    decoder_output_nodes = decoder.get_outputs()
-
-    joiner_input_nodes = joiner.get_inputs()
-    joiner_output_nodes = joiner.get_outputs()
-
     decoder_input = torch.tensor(
         hyps,
         dtype=torch.int64,
     )  # (N, context_size)
 
-    decoder_out = decoder.run(
-        [decoder_output_nodes[0].name],
-        {
-            decoder_input_nodes[0].name: decoder_input.numpy(),
-        },
-    )[0].squeeze(1)
-    projected_decoder_out = joiner_decoder_proj.run(
-        [joiner_decoder_proj.get_outputs()[0].name],
-        {joiner_decoder_proj.get_inputs()[0].name: decoder_out},
-    )[0]
-
-    projected_decoder_out = torch.from_numpy(projected_decoder_out)
+    decoder_out = model.run_decoder(decoder_input)
 
     offset = 0
     for batch_size in batch_size_list:
         start = offset
         end = offset + batch_size
-        current_encoder_out = projected_encoder_out[start:end]
-        # current_encoder_out's shape: (batch_size, encoder_out_dim)
+        current_encoder_out = packed_encoder_out.data[start:end]
+        # current_encoder_out's shape: (batch_size, joiner_dim)
         offset = end
 
-        projected_decoder_out = projected_decoder_out[:batch_size]
+        decoder_out = decoder_out[:batch_size]
+        logits = model.run_joiner(current_encoder_out, decoder_out)
 
-        logits = joiner.run(
-            [joiner_output_nodes[0].name],
-            {
-                joiner_input_nodes[0].name: current_encoder_out,
-                joiner_input_nodes[1].name: projected_decoder_out.numpy(),
-            },
-        )[0]
-        logits = torch.from_numpy(logits).squeeze(1).squeeze(1)
         # logits'shape (batch_size, vocab_size)
 
         assert logits.ndim == 2, logits.shape
@@ -261,17 +337,7 @@ def greedy_search(
                 decoder_input,
                 dtype=torch.int64,
             )
-            decoder_out = decoder.run(
-                [decoder_output_nodes[0].name],
-                {
-                    decoder_input_nodes[0].name: decoder_input.numpy(),
-                },
-            )[0].squeeze(1)
-            projected_decoder_out = joiner_decoder_proj.run(
-                [joiner_decoder_proj.get_outputs()[0].name],
-                {joiner_decoder_proj.get_inputs()[0].name: decoder_out},
-            )[0]
-            projected_decoder_out = torch.from_numpy(projected_decoder_out)
+            decoder_out = model.run_decoder(decoder_input)
 
     sorted_ans = [h[context_size:] for h in hyps]
     ans = []
@@ -287,39 +353,12 @@ def main():
     parser = get_parser()
     args = parser.parse_args()
     logging.info(vars(args))
-
-    session_opts = ort.SessionOptions()
-    session_opts.inter_op_num_threads = 1
-    session_opts.intra_op_num_threads = 1
-
-    encoder = ort.InferenceSession(
-        args.encoder_model_filename,
-        sess_options=session_opts,
+    model = OnnxModel(
+        encoder_model_filename=args.encoder_model_filename,
+        decoder_model_filename=args.decoder_model_filename,
+        joiner_model_filename=args.joiner_model_filename,
     )
 
-    decoder = ort.InferenceSession(
-        args.decoder_model_filename,
-        sess_options=session_opts,
-    )
-
-    joiner = ort.InferenceSession(
-        args.joiner_model_filename,
-        sess_options=session_opts,
-    )
-
-    joiner_encoder_proj = ort.InferenceSession(
-        args.joiner_encoder_proj_model_filename,
-        sess_options=session_opts,
-    )
-
-    joiner_decoder_proj = ort.InferenceSession(
-        args.joiner_decoder_proj_model_filename,
-        sess_options=session_opts,
-    )
-
-    sp = spm.SentencePieceProcessor()
-    sp.load(args.bpe_model)
-
     logging.info("Constructing Fbank computer")
     opts = kaldifeat.FbankOptions()
     opts.device = "cpu"
@@ -347,30 +386,27 @@ def main():
     )
 
     feature_lengths = torch.tensor(feature_lengths, dtype=torch.int64)
-
-    encoder_input_nodes = encoder.get_inputs()
-    encoder_out_nodes = encoder.get_outputs()
-    encoder_out, encoder_out_lens = encoder.run(
-        [encoder_out_nodes[0].name, encoder_out_nodes[1].name],
-        {
-            encoder_input_nodes[0].name: features.numpy(),
-            encoder_input_nodes[1].name: feature_lengths.numpy(),
-        },
-    )
+    encoder_out, encoder_out_lens = model.run_encoder(features, feature_lengths)
 
     hyps = greedy_search(
-        decoder=decoder,
-        joiner=joiner,
-        joiner_encoder_proj=joiner_encoder_proj,
-        joiner_decoder_proj=joiner_decoder_proj,
+        model=model,
         encoder_out=encoder_out,
         encoder_out_lens=encoder_out_lens,
-        context_size=args.context_size,
     )
     s = "\n"
+
+    symbol_table = k2.SymbolTable.from_file(args.tokens)
+
+    def token_ids_to_words(token_ids: List[int]) -> str:
+        text = ""
+        for i in token_ids:
+            text += symbol_table[i]
+        return text.replace("▁", " ").strip()
+
+    context_size = model.context_size
     for filename, hyp in zip(args.sound_files, hyps):
-        words = sp.decode(hyp)
-        s += f"{filename}:\n{words}\n\n"
+        words = token_ids_to_words(hyp[context_size:])
+        s += f"{filename}:\n{words}\n"
     logging.info(s)
 
     logging.info("Decoding Done")
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless5/conformer.py b/egs/librispeech/ASR/pruned_transducer_stateless5/conformer.py
index b3a7d71bc..8bbceec61 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless5/conformer.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless5/conformer.py
@@ -32,7 +32,7 @@ from scaling import (
 )
 from torch import Tensor, nn
 
-from icefall.utils import make_pad_mask, subsequent_chunk_mask
+from icefall.utils import is_jit_tracing, make_pad_mask, subsequent_chunk_mask
 
 
 class Conformer(EncoderInterface):
@@ -1012,15 +1012,28 @@ class RelPositionMultiheadAttention(nn.Module):
             n == left_context + 2 * time1 - 1
         ), f"{n} == {left_context} + 2 * {time1} - 1"
         # Note: TorchScript requires explicit arg for stride()
-        batch_stride = x.stride(0)
-        head_stride = x.stride(1)
-        time1_stride = x.stride(2)
-        n_stride = x.stride(3)
-        return x.as_strided(
-            (batch_size, num_heads, time1, time2),
-            (batch_stride, head_stride, time1_stride - n_stride, n_stride),
-            storage_offset=n_stride * (time1 - 1),
-        )
+
+        if is_jit_tracing():
+            rows = torch.arange(start=time1 - 1, end=-1, step=-1)
+            cols = torch.arange(time2)
+            rows = rows.repeat(batch_size * num_heads).unsqueeze(-1)
+            indexes = rows + cols
+
+            x = x.reshape(-1, n)
+            x = torch.gather(x, dim=1, index=indexes)
+            x = x.reshape(batch_size, num_heads, time1, time2)
+            return x
+        else:
+            # Note: TorchScript requires explicit arg for stride()
+            batch_stride = x.stride(0)
+            head_stride = x.stride(1)
+            time1_stride = x.stride(2)
+            n_stride = x.stride(3)
+            return x.as_strided(
+                (batch_size, num_heads, time1, time2),
+                (batch_stride, head_stride, time1_stride - n_stride, n_stride),
+                storage_offset=n_stride * (time1 - 1),
+            )
 
     def multi_head_attention_forward(
         self,
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless5/export-onnx.py b/egs/librispeech/ASR/pruned_transducer_stateless5/export-onnx.py
new file mode 100755
index 000000000..743fe8a92
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless5/export-onnx.py
@@ -0,0 +1,565 @@
+#!/usr/bin/env python3
+#
+# Copyright 2023 Xiaomi Corporation (Author: Fangjun Kuang)
+
+"""
+This script exports a transducer model from PyTorch to ONNX.
+
+We use the pre-trained model from
+https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless5-2022-05-13
+as an example to show how to use this file.
+
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless5-2022-05-13
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained-epoch-39-avg-7.pt"
+
+cd exp
+ln -s pretrained-epoch-39-avg-7.pt epoch-99.pt
+popd
+
+2. Export the model to ONNX
+
+./pruned_transducer_stateless5/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --epoch 99 \
+  --avg 1 \
+  --use-averaged-model 0 \
+  --exp-dir $repo/exp \
+  --num-encoder-layers 18 \
+  --dim-feedforward 2048 \
+  --nhead 8 \
+  --encoder-dim 512 \
+  --decoder-dim 512 \
+  --joiner-dim 512
+
+It will generate the following 3 files inside $repo/exp:
+
+  - encoder-epoch-99-avg-1.onnx
+  - decoder-epoch-99-avg-1.onnx
+  - joiner-epoch-99-avg-1.onnx
+
+See ./onnx_pretrained.py and ./onnx_check.py for how to
+use the exported ONNX models.
+"""
+
+import argparse
+import logging
+from pathlib import Path
+from typing import Dict, Tuple
+
+import onnx
+import sentencepiece as spm
+import torch
+import torch.nn as nn
+from conformer import Conformer
+from decoder import Decoder
+from scaling_converter import convert_scaled_to_non_scaled
+from train import add_model_arguments, get_params, get_transducer_model
+
+from icefall.checkpoint import (
+    average_checkpoints,
+    average_checkpoints_with_averaged_model,
+    find_checkpoints,
+    load_checkpoint,
+)
+from icefall.utils import setup_logger, str2bool
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--epoch",
+        type=int,
+        default=28,
+        help="""It specifies the checkpoint to use for averaging.
+        Note: Epoch counts from 0.
+        You can specify --avg to use more checkpoints for model averaging.""",
+    )
+
+    parser.add_argument(
+        "--iter",
+        type=int,
+        default=0,
+        help="""If positive, --epoch is ignored and it
+        will use the checkpoint exp_dir/checkpoint-iter.pt.
+        You can specify --avg to use more checkpoints for model averaging.
+        """,
+    )
+
+    parser.add_argument(
+        "--avg",
+        type=int,
+        default=15,
+        help="Number of checkpoints to average. Automatically select "
+        "consecutive checkpoints before the checkpoint specified by "
+        "'--epoch' and '--iter'",
+    )
+
+    parser.add_argument(
+        "--use-averaged-model",
+        type=str2bool,
+        default=True,
+        help="Whether to load averaged model. Currently it only supports "
+        "using --epoch. If True, it would decode with the averaged model "
+        "over the epoch range from `epoch-avg` (excluded) to `epoch`."
+        "Actually only the models with epoch number of `epoch-avg` and "
+        "`epoch` are loaded for averaging. ",
+    )
+
+    parser.add_argument(
+        "--exp-dir",
+        type=str,
+        default="pruned_transducer_stateless5/exp",
+        help="""It specifies the directory where all training related
+        files, e.g., checkpoints, log, etc, are saved
+        """,
+    )
+
+    parser.add_argument(
+        "--bpe-model",
+        type=str,
+        default="data/lang_bpe_500/bpe.model",
+        help="Path to the BPE model",
+    )
+
+    parser.add_argument(
+        "--context-size",
+        type=int,
+        default=2,
+        help="The context size in the decoder. 1 means bigram; 2 means tri-gram",
+    )
+
+    add_model_arguments(parser)
+
+    return parser
+
+
+def add_meta_data(filename: str, meta_data: Dict[str, str]):
+    """Add meta data to an ONNX model. It is changed in-place.
+
+    Args:
+      filename:
+        Filename of the ONNX model to be changed.
+      meta_data:
+        Key-value pairs.
+    """
+    model = onnx.load(filename)
+    for key, value in meta_data.items():
+        meta = model.metadata_props.add()
+        meta.key = key
+        meta.value = value
+
+    onnx.save(model, filename)
+
+
+class OnnxEncoder(nn.Module):
+    """A wrapper for Conformer and the encoder_proj from the joiner"""
+
+    def __init__(self, encoder: Conformer, encoder_proj: nn.Linear):
+        """
+        Args:
+          encoder:
+            A Conformer encoder.
+          encoder_proj:
+            The projection layer for encoder from the joiner.
+        """
+        super().__init__()
+        self.encoder = encoder
+        self.encoder_proj = encoder_proj
+
+    def forward(
+        self,
+        x: torch.Tensor,
+        x_lens: torch.Tensor,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """Please see the help information of Conformer.forward
+
+        Args:
+          x:
+            A 3-D tensor of shape (N, T, C)
+          x_lens:
+            A 1-D tensor of shape (N,). Its dtype is torch.int64
+        Returns:
+          Return a tuple containing:
+            - encoder_out, A 3-D tensor of shape (N, T', joiner_dim)
+            - encoder_out_lens, A 1-D tensor of shape (N,)
+        """
+        encoder_out, encoder_out_lens = self.encoder(x, x_lens)
+
+        encoder_out = self.encoder_proj(encoder_out)
+        # Now encoder_out is of shape (N, T, joiner_dim)
+
+        return encoder_out, encoder_out_lens
+
+
+class OnnxDecoder(nn.Module):
+    """A wrapper for Decoder and the decoder_proj from the joiner"""
+
+    def __init__(self, decoder: Decoder, decoder_proj: nn.Linear):
+        super().__init__()
+        self.decoder = decoder
+        self.decoder_proj = decoder_proj
+
+    def forward(self, y: torch.Tensor) -> torch.Tensor:
+        """
+        Args:
+          y:
+            A 2-D tensor of shape (N, context_size).
+        Returns
+          Return a 2-D tensor of shape (N, joiner_dim)
+        """
+        need_pad = False
+        decoder_output = self.decoder(y, need_pad=need_pad)
+        decoder_output = decoder_output.squeeze(1)
+        output = self.decoder_proj(decoder_output)
+
+        return output
+
+
+class OnnxJoiner(nn.Module):
+    """A wrapper for the joiner"""
+
+    def __init__(self, output_linear: nn.Linear):
+        super().__init__()
+        self.output_linear = output_linear
+
+    def forward(
+        self,
+        encoder_out: torch.Tensor,
+        decoder_out: torch.Tensor,
+    ) -> torch.Tensor:
+        """
+        Args:
+          encoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+          decoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+        Returns:
+          Return a 2-D tensor of shape (N, vocab_size)
+        """
+        logit = encoder_out + decoder_out
+        logit = self.output_linear(torch.tanh(logit))
+        return logit
+
+
+def export_encoder_model_onnx(
+    encoder_model: OnnxEncoder,
+    encoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the given encoder model to ONNX format.
+    The exported model has two inputs:
+
+        - x, a tensor of shape (N, T, C); dtype is torch.float32
+        - x_lens, a tensor of shape (N,); dtype is torch.int64
+
+    and it has two outputs:
+
+        - encoder_out, a tensor of shape (N, T', joiner_dim)
+        - encoder_out_lens, a tensor of shape (N,)
+
+    Args:
+      encoder_model:
+        The input encoder model
+      encoder_filename:
+        The filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    x = torch.zeros(1, 100, 80, dtype=torch.float32)
+    x_lens = torch.tensor([100], dtype=torch.int64)
+
+    torch.onnx.export(
+        encoder_model,
+        (x, x_lens),
+        encoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["x", "x_lens"],
+        output_names=["encoder_out", "encoder_out_lens"],
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "x_lens": {0: "N"},
+            "encoder_out": {0: "N", 1: "T"},
+            "encoder_out_lens": {0: "N"},
+        },
+    )
+
+
+def export_decoder_model_onnx(
+    decoder_model: OnnxDecoder,
+    decoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the decoder model to ONNX format.
+
+    The exported model has one input:
+
+        - y: a torch.int64 tensor of shape (N, decoder_model.context_size)
+
+    and has one output:
+
+        - decoder_out: a torch.float32 tensor of shape (N, joiner_dim)
+
+    Args:
+      decoder_model:
+        The decoder model to be exported.
+      decoder_filename:
+        Filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    context_size = decoder_model.decoder.context_size
+    vocab_size = decoder_model.decoder.vocab_size
+
+    y = torch.zeros(10, context_size, dtype=torch.int64)
+    torch.onnx.export(
+        decoder_model,
+        y,
+        decoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["y"],
+        output_names=["decoder_out"],
+        dynamic_axes={
+            "y": {0: "N"},
+            "decoder_out": {0: "N"},
+        },
+    )
+
+    meta_data = {
+        "context_size": str(context_size),
+        "vocab_size": str(vocab_size),
+    }
+    add_meta_data(filename=decoder_filename, meta_data=meta_data)
+
+
+def export_joiner_model_onnx(
+    joiner_model: nn.Module,
+    joiner_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the joiner model to ONNX format.
+    The exported joiner model has two inputs:
+
+        - encoder_out: a tensor of shape (N, joiner_dim)
+        - decoder_out: a tensor of shape (N, joiner_dim)
+
+    and produces one output:
+
+        - logit: a tensor of shape (N, vocab_size)
+    """
+    joiner_dim = joiner_model.output_linear.weight.shape[1]
+    logging.info(f"joiner dim: {joiner_dim}")
+
+    projected_encoder_out = torch.rand(11, joiner_dim, dtype=torch.float32)
+    projected_decoder_out = torch.rand(11, joiner_dim, dtype=torch.float32)
+
+    torch.onnx.export(
+        joiner_model,
+        (projected_encoder_out, projected_decoder_out),
+        joiner_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=[
+            "encoder_out",
+            "decoder_out",
+        ],
+        output_names=["logit"],
+        dynamic_axes={
+            "encoder_out": {0: "N"},
+            "decoder_out": {0: "N"},
+            "logit": {0: "N"},
+        },
+    )
+    meta_data = {
+        "joiner_dim": str(joiner_dim),
+    }
+    add_meta_data(filename=joiner_filename, meta_data=meta_data)
+
+
+@torch.no_grad()
+def main():
+    args = get_parser().parse_args()
+    args.exp_dir = Path(args.exp_dir)
+
+    params = get_params()
+    params.update(vars(args))
+
+    device = torch.device("cpu")
+    if torch.cuda.is_available():
+        device = torch.device("cuda", 0)
+
+    setup_logger(f"{params.exp_dir}/log-export/log-export-onnx")
+
+    logging.info(f"device: {device}")
+
+    sp = spm.SentencePieceProcessor()
+    sp.load(params.bpe_model)
+
+    # <blk> is defined in local/train_bpe_model.py
+    params.blank_id = sp.piece_to_id("<blk>")
+    params.vocab_size = sp.get_piece_size()
+
+    logging.info(params)
+
+    logging.info("About to create model")
+    model = get_transducer_model(params)
+
+    model.to(device)
+
+    if not params.use_averaged_model:
+        if params.iter > 0:
+            filenames = find_checkpoints(params.exp_dir, iteration=-params.iter)[
+                : params.avg
+            ]
+            if len(filenames) == 0:
+                raise ValueError(
+                    f"No checkpoints found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            elif len(filenames) < params.avg:
+                raise ValueError(
+                    f"Not enough checkpoints ({len(filenames)}) found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            logging.info(f"averaging {filenames}")
+            model.to(device)
+            model.load_state_dict(average_checkpoints(filenames, device=device))
+        elif params.avg == 1:
+            load_checkpoint(f"{params.exp_dir}/epoch-{params.epoch}.pt", model)
+        else:
+            start = params.epoch - params.avg + 1
+            filenames = []
+            for i in range(start, params.epoch + 1):
+                if i >= 1:
+                    filenames.append(f"{params.exp_dir}/epoch-{i}.pt")
+            logging.info(f"averaging {filenames}")
+            model.to(device)
+            model.load_state_dict(average_checkpoints(filenames, device=device))
+    else:
+        if params.iter > 0:
+            filenames = find_checkpoints(params.exp_dir, iteration=-params.iter)[
+                : params.avg + 1
+            ]
+            if len(filenames) == 0:
+                raise ValueError(
+                    f"No checkpoints found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            elif len(filenames) < params.avg + 1:
+                raise ValueError(
+                    f"Not enough checkpoints ({len(filenames)}) found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            filename_start = filenames[-1]
+            filename_end = filenames[0]
+            logging.info(
+                "Calculating the averaged model over iteration checkpoints"
+                f" from {filename_start} (excluded) to {filename_end}"
+            )
+            model.to(device)
+            model.load_state_dict(
+                average_checkpoints_with_averaged_model(
+                    filename_start=filename_start,
+                    filename_end=filename_end,
+                    device=device,
+                )
+            )
+        else:
+            assert params.avg > 0, params.avg
+            start = params.epoch - params.avg
+            assert start >= 1, start
+            filename_start = f"{params.exp_dir}/epoch-{start}.pt"
+            filename_end = f"{params.exp_dir}/epoch-{params.epoch}.pt"
+            logging.info(
+                f"Calculating the averaged model over epoch range from "
+                f"{start} (excluded) to {params.epoch}"
+            )
+            model.to(device)
+            model.load_state_dict(
+                average_checkpoints_with_averaged_model(
+                    filename_start=filename_start,
+                    filename_end=filename_end,
+                    device=device,
+                )
+            )
+
+    model.to("cpu")
+    model.eval()
+
+    convert_scaled_to_non_scaled(model, inplace=True)
+
+    encoder = OnnxEncoder(
+        encoder=model.encoder,
+        encoder_proj=model.joiner.encoder_proj,
+    )
+
+    decoder = OnnxDecoder(
+        decoder=model.decoder,
+        decoder_proj=model.joiner.decoder_proj,
+    )
+
+    joiner = OnnxJoiner(output_linear=model.joiner.output_linear)
+
+    encoder_num_param = sum([p.numel() for p in encoder.parameters()])
+    decoder_num_param = sum([p.numel() for p in decoder.parameters()])
+    joiner_num_param = sum([p.numel() for p in joiner.parameters()])
+    total_num_param = encoder_num_param + decoder_num_param + joiner_num_param
+    logging.info(f"encoder parameters: {encoder_num_param}")
+    logging.info(f"decoder parameters: {decoder_num_param}")
+    logging.info(f"joiner parameters: {joiner_num_param}")
+    logging.info(f"total parameters: {total_num_param}")
+
+    if params.iter > 0:
+        suffix = f"iter-{params.iter}"
+    else:
+        suffix = f"epoch-{params.epoch}"
+
+    suffix += f"-avg-{params.avg}"
+
+    opset_version = 13
+
+    logging.info("Exporting encoder")
+    encoder_filename = params.exp_dir / f"encoder-{suffix}.onnx"
+    export_encoder_model_onnx(
+        encoder,
+        encoder_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported encoder to {encoder_filename}")
+
+    logging.info("Exporting decoder")
+    decoder_filename = params.exp_dir / f"decoder-{suffix}.onnx"
+    export_decoder_model_onnx(
+        decoder,
+        decoder_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported decoder to {decoder_filename}")
+
+    logging.info("Exporting joiner")
+    joiner_filename = params.exp_dir / f"joiner-{suffix}.onnx"
+    export_joiner_model_onnx(
+        joiner,
+        joiner_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported joiner to {joiner_filename}")
+
+
+if __name__ == "__main__":
+    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
+
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless5/onnx_check.py b/egs/librispeech/ASR/pruned_transducer_stateless5/onnx_check.py
new file mode 120000
index 000000000..66d63b807
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless5/onnx_check.py
@@ -0,0 +1 @@
+../pruned_transducer_stateless3/onnx_check.py
\ No newline at end of file
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless5/onnx_pretrained.py b/egs/librispeech/ASR/pruned_transducer_stateless5/onnx_pretrained.py
new file mode 120000
index 000000000..7607623c8
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless5/onnx_pretrained.py
@@ -0,0 +1 @@
+../pruned_transducer_stateless3/onnx_pretrained.py
\ No newline at end of file
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/generate_averaged_model.py b/egs/librispeech/ASR/pruned_transducer_stateless7/generate_averaged_model.py
new file mode 100755
index 000000000..381772ce7
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/generate_averaged_model.py
@@ -0,0 +1,203 @@
+#!/usr/bin/env python3
+#
+# Copyright 2021-2022 Xiaomi Corporation (Author: Yifan Yang)
+#
+# See ../../../../LICENSE for clarification regarding multiple authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Usage:
+(1) use the checkpoint exp_dir/epoch-xxx.pt
+./pruned_transducer_stateless7/generate_averaged_model.py \
+    --epoch 28 \
+    --avg 15 \
+    --exp-dir ./pruned_transducer_stateless7/exp
+
+It will generate a file `epoch-28-avg-15.pt` in the given `exp_dir`.
+You can later load it by `torch.load("epoch-28-avg-15.pt")`.
+
+(2) use the checkpoint exp_dir/checkpoint-iter.pt
+./pruned_transducer_stateless7/generate_averaged_model.py \
+    --iter 22000 \
+    --avg 5 \
+    --exp-dir ./pruned_transducer_stateless7/exp
+
+It will generate a file `iter-22000-avg-5.pt` in the given `exp_dir`.
+You can later load it by `torch.load("iter-22000-avg-5.pt")`.
+"""
+
+
+import argparse
+from pathlib import Path
+from typing import Dict, List
+
+import sentencepiece as spm
+import torch
+from asr_datamodule import LibriSpeechAsrDataModule
+
+from train import add_model_arguments, get_params, get_transducer_model
+
+from icefall.checkpoint import (
+    average_checkpoints_with_averaged_model,
+    find_checkpoints,
+)
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--epoch",
+        type=int,
+        default=30,
+        help="""It specifies the checkpoint to use for decoding.
+        Note: Epoch counts from 1.
+        You can specify --avg to use more checkpoints for model averaging.""",
+    )
+
+    parser.add_argument(
+        "--iter",
+        type=int,
+        default=0,
+        help="""If positive, --epoch is ignored and it
+        will use the checkpoint exp_dir/checkpoint-iter.pt.
+        You can specify --avg to use more checkpoints for model averaging.
+        """,
+    )
+
+    parser.add_argument(
+        "--avg",
+        type=int,
+        default=9,
+        help="Number of checkpoints to average. Automatically select "
+        "consecutive checkpoints before the checkpoint specified by "
+        "'--epoch' and '--iter'",
+    )
+
+    parser.add_argument(
+        "--exp-dir",
+        type=str,
+        default="pruned_transducer_stateless7/exp",
+        help="The experiment dir",
+    )
+
+    parser.add_argument(
+        "--bpe-model",
+        type=str,
+        default="data/lang_bpe_500/bpe.model",
+        help="Path to the BPE model",
+    )
+
+    parser.add_argument(
+        "--context-size",
+        type=int,
+        default=2,
+        help="The context size in the decoder. 1 means bigram; 2 means tri-gram",
+    )
+
+    add_model_arguments(parser)
+
+    return parser
+
+
+@torch.no_grad()
+def main():
+    parser = get_parser()
+    LibriSpeechAsrDataModule.add_arguments(parser)
+    args = parser.parse_args()
+    args.exp_dir = Path(args.exp_dir)
+
+    params = get_params()
+    params.update(vars(args))
+
+    if params.iter > 0:
+        params.suffix = f"iter-{params.iter}-avg-{params.avg}"
+    else:
+        params.suffix = f"epoch-{params.epoch}-avg-{params.avg}"
+
+    print("Script started")
+
+    device = torch.device("cpu")
+    print(f"Device: {device}")
+
+    sp = spm.SentencePieceProcessor()
+    sp.load(params.bpe_model)
+
+    # <blk> is defined in local/train_bpe_model.py
+    params.blank_id = sp.piece_to_id("<blk>")
+    params.unk_id = sp.piece_to_id("<unk>")
+    params.vocab_size = sp.get_piece_size()
+
+    print("About to create model")
+    model = get_transducer_model(params)
+
+    if params.iter > 0:
+        filenames = find_checkpoints(params.exp_dir, iteration=-params.iter)[
+            : params.avg + 1
+        ]
+        if len(filenames) == 0:
+            raise ValueError(
+                f"No checkpoints found for --iter {params.iter}, --avg {params.avg}"
+            )
+        elif len(filenames) < params.avg + 1:
+            raise ValueError(
+                f"Not enough checkpoints ({len(filenames)}) found for"
+                f" --iter {params.iter}, --avg {params.avg}"
+            )
+        filename_start = filenames[-1]
+        filename_end = filenames[0]
+        print(
+            "Calculating the averaged model over iteration checkpoints"
+            f" from {filename_start} (excluded) to {filename_end}"
+        )
+        model.to(device)
+        model.load_state_dict(
+            average_checkpoints_with_averaged_model(
+                filename_start=filename_start,
+                filename_end=filename_end,
+                device=device,
+            )
+        )
+        filename = params.exp_dir / f"iter-{params.iter}-avg-{params.avg}.pt"
+        torch.save({"model": model.state_dict()}, filename)
+    else:
+        assert params.avg > 0, params.avg
+        start = params.epoch - params.avg
+        assert start >= 1, start
+        filename_start = f"{params.exp_dir}/epoch-{start}.pt"
+        filename_end = f"{params.exp_dir}/epoch-{params.epoch}.pt"
+        print(
+            f"Calculating the averaged model over epoch range from "
+            f"{start} (excluded) to {params.epoch}"
+        )
+        model.to(device)
+        model.load_state_dict(
+            average_checkpoints_with_averaged_model(
+                filename_start=filename_start,
+                filename_end=filename_end,
+                device=device,
+            )
+        )
+        filename = params.exp_dir / f"epoch-{params.epoch}-avg-{params.avg}.pt"
+        torch.save({"model": model.state_dict()}, filename)
+
+    num_param = sum([p.numel() for p in model.parameters()])
+    print(f"Number of model parameters: {num_param}")
+
+    print("Done!")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/export-onnx.py b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/export-onnx.py
new file mode 100755
index 000000000..35d6b0556
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/export-onnx.py
@@ -0,0 +1,639 @@
+#!/usr/bin/env python3
+#
+# Copyright 2023 Xiaomi Corporation (Author: Fangjun Kuang)
+
+"""
+This script exports a transducer model from PyTorch to ONNX.
+
+We use the pre-trained model from
+https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+as an example to show how to use this file.
+
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained.pt"
+cd exp
+ln -s pretrained.pt epoch-99.pt
+popd
+
+2. Export the model to ONNX
+
+./pruned_transducer_stateless7_streaming/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --use-averaged-model 0 \
+  --epoch 99 \
+  --avg 1 \
+  --decode-chunk-len 32 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files in $repo/exp
+
+  - encoder-epoch-99-avg-1.onnx
+  - decoder-epoch-99-avg-1.onnx
+  - joiner-epoch-99-avg-1.onnx
+
+See ./onnx_pretrained.py for how to use the exported models.
+"""
+
+import argparse
+import logging
+from pathlib import Path
+from typing import Dict, List, Tuple
+
+import onnx
+import sentencepiece as spm
+import torch
+import torch.nn as nn
+from decoder import Decoder
+from scaling_converter import convert_scaled_to_non_scaled
+from torch import Tensor
+from train import add_model_arguments, get_params, get_transducer_model
+from zipformer import Zipformer
+
+from icefall.checkpoint import (
+    average_checkpoints,
+    average_checkpoints_with_averaged_model,
+    find_checkpoints,
+    load_checkpoint,
+)
+from icefall.utils import setup_logger, str2bool
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--epoch",
+        type=int,
+        default=30,
+        help="""It specifies the checkpoint to use for decoding.
+        Note: Epoch counts from 1.
+        You can specify --avg to use more checkpoints for model averaging.""",
+    )
+
+    parser.add_argument(
+        "--iter",
+        type=int,
+        default=0,
+        help="""If positive, --epoch is ignored and it
+        will use the checkpoint exp_dir/checkpoint-iter.pt.
+        You can specify --avg to use more checkpoints for model averaging.
+        """,
+    )
+
+    parser.add_argument(
+        "--avg",
+        type=int,
+        default=9,
+        help="Number of checkpoints to average. Automatically select "
+        "consecutive checkpoints before the checkpoint specified by "
+        "'--epoch' and '--iter'",
+    )
+
+    parser.add_argument(
+        "--use-averaged-model",
+        type=str2bool,
+        default=True,
+        help="Whether to load averaged model. Currently it only supports "
+        "using --epoch. If True, it would decode with the averaged model "
+        "over the epoch range from `epoch-avg` (excluded) to `epoch`."
+        "Actually only the models with epoch number of `epoch-avg` and "
+        "`epoch` are loaded for averaging. ",
+    )
+
+    parser.add_argument(
+        "--exp-dir",
+        type=str,
+        default="pruned_transducer_stateless7_streaming/exp",
+        help="""It specifies the directory where all training related
+        files, e.g., checkpoints, log, etc, are saved
+        """,
+    )
+
+    parser.add_argument(
+        "--bpe-model",
+        type=str,
+        default="data/lang_bpe_500/bpe.model",
+        help="Path to the BPE model",
+    )
+
+    parser.add_argument(
+        "--context-size",
+        type=int,
+        default=2,
+        help="The context size in the decoder. 1 means bigram; 2 means tri-gram",
+    )
+
+    add_model_arguments(parser)
+
+    return parser
+
+
+class OnnxEncoder(nn.Module):
+    """A wrapper for Zipformer and the encoder_proj from the joiner"""
+
+    def __init__(self, encoder: Zipformer, encoder_proj: nn.Linear):
+        """
+        Args:
+          encoder:
+            A Zipformer encoder.
+          encoder_proj:
+            The projection layer for encoder from the joiner.
+        """
+        super().__init__()
+        self.encoder = encoder
+        self.encoder_proj = encoder_proj
+
+    def forward(self, x: Tensor, states: List[Tensor]) -> Tuple[Tensor, List[Tensor]]:
+        """Please see the help information of Zipformer.streaming_forward"""
+        N = x.size(0)
+        T = x.size(1)
+        x_lens = torch.tensor([T] * N, device=x.device)
+
+        output, _, new_states = self.encoder.streaming_forward(
+            x=x,
+            x_lens=x_lens,
+            states=states,
+        )
+
+        output = self.encoder_proj(output)
+        # Now output is of shape (N, T, joiner_dim)
+
+        return output, new_states
+
+
+class OnnxDecoder(nn.Module):
+    """A wrapper for Decoder and the decoder_proj from the joiner"""
+
+    def __init__(self, decoder: Decoder, decoder_proj: nn.Linear):
+        super().__init__()
+        self.decoder = decoder
+        self.decoder_proj = decoder_proj
+
+    def forward(self, y: torch.Tensor) -> torch.Tensor:
+        """
+        Args:
+          y:
+            A 2-D tensor of shape (N, context_size).
+        Returns
+          Return a 2-D tensor of shape (N, joiner_dim)
+        """
+        need_pad = False
+        decoder_output = self.decoder(y, need_pad=need_pad)
+        decoder_output = decoder_output.squeeze(1)
+        output = self.decoder_proj(decoder_output)
+
+        return output
+
+
+class OnnxJoiner(nn.Module):
+    """A wrapper for the joiner"""
+
+    def __init__(self, output_linear: nn.Linear):
+        super().__init__()
+        self.output_linear = output_linear
+
+    def forward(
+        self,
+        encoder_out: torch.Tensor,
+        decoder_out: torch.Tensor,
+    ) -> torch.Tensor:
+        """
+        Args:
+          encoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+          decoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+        Returns:
+          Return a 2-D tensor of shape (N, vocab_size)
+        """
+        logit = encoder_out + decoder_out
+        logit = self.output_linear(torch.tanh(logit))
+        return logit
+
+
+def add_meta_data(filename: str, meta_data: Dict[str, str]):
+    """Add meta data to an ONNX model. It is changed in-place.
+
+    Args:
+      filename:
+        Filename of the ONNX model to be changed.
+      meta_data:
+        Key-value pairs.
+    """
+    model = onnx.load(filename)
+    for key, value in meta_data.items():
+        meta = model.metadata_props.add()
+        meta.key = key
+        meta.value = value
+
+    onnx.save(model, filename)
+
+
+def export_encoder_model_onnx(
+    encoder_model: OnnxEncoder,
+    encoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """
+    Onnx model inputs:
+      - 0: src
+      - many state tensors (the exact number depending on the actual model)
+
+    Onnx model outputs:
+      - 0: output, its shape is (N, T, joiner_dim)
+      - many state tensors (the exact number depending on the actual model)
+
+    Args:
+      encoder_model:
+        The model to be exported
+      encoder_filename:
+        The filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+
+    encoder_model.encoder.__class__.forward = (
+        encoder_model.encoder.__class__.streaming_forward
+    )
+
+    decode_chunk_len = encoder_model.encoder.decode_chunk_size * 2
+    pad_length = 7
+    T = decode_chunk_len + pad_length
+    logging.info(f"decode_chunk_len: {decode_chunk_len}")
+    logging.info(f"pad_length: {pad_length}")
+    logging.info(f"T: {T}")
+
+    x = torch.rand(1, T, 80, dtype=torch.float32)
+
+    init_state = encoder_model.encoder.get_init_state()
+
+    num_encoders = encoder_model.encoder.num_encoders
+    logging.info(f"num_encoders: {num_encoders}")
+    logging.info(f"len(init_state): {len(init_state)}")
+
+    inputs = {}
+    input_names = ["x"]
+
+    outputs = {}
+    output_names = ["encoder_out"]
+
+    def build_inputs_outputs(tensors, name, N):
+        for i, s in enumerate(tensors):
+            logging.info(f"{name}_{i}.shape: {s.shape}")
+            inputs[f"{name}_{i}"] = {N: "N"}
+            outputs[f"new_{name}_{i}"] = {N: "N"}
+            input_names.append(f"{name}_{i}")
+            output_names.append(f"new_{name}_{i}")
+
+    num_encoder_layers = ",".join(map(str, encoder_model.encoder.num_encoder_layers))
+    encoder_dims = ",".join(map(str, encoder_model.encoder.encoder_dims))
+    attention_dims = ",".join(map(str, encoder_model.encoder.attention_dims))
+    cnn_module_kernels = ",".join(map(str, encoder_model.encoder.cnn_module_kernels))
+    ds = encoder_model.encoder.zipformer_downsampling_factors
+    left_context_len = encoder_model.encoder.left_context_len
+    left_context_len = [left_context_len // k for k in ds]
+    left_context_len = ",".join(map(str, left_context_len))
+
+    meta_data = {
+        "model_type": "streaming_zipformer",
+        "version": "1",
+        "model_author": "k2-fsa",
+        "decode_chunk_len": str(decode_chunk_len),  # 32
+        "pad_length": str(pad_length),  # 7
+        "num_encoder_layers": num_encoder_layers,
+        "encoder_dims": encoder_dims,
+        "attention_dims": attention_dims,
+        "cnn_module_kernels": cnn_module_kernels,
+        "left_context_len": left_context_len,
+    }
+    logging.info(f"meta_data: {meta_data}")
+
+    # (num_encoder_layers, 1)
+    cached_len = init_state[num_encoders * 0 : num_encoders * 1]
+
+    # (num_encoder_layers, 1, encoder_dim)
+    cached_avg = init_state[num_encoders * 1 : num_encoders * 2]
+
+    # (num_encoder_layers, left_context_len, 1, attention_dim)
+    cached_key = init_state[num_encoders * 2 : num_encoders * 3]
+
+    # (num_encoder_layers, left_context_len, 1, attention_dim//2)
+    cached_val = init_state[num_encoders * 3 : num_encoders * 4]
+
+    # (num_encoder_layers, left_context_len, 1, attention_dim//2)
+    cached_val2 = init_state[num_encoders * 4 : num_encoders * 5]
+
+    # (num_encoder_layers, 1, encoder_dim, cnn_module_kernel-1)
+    cached_conv1 = init_state[num_encoders * 5 : num_encoders * 6]
+
+    # (num_encoder_layers, 1, encoder_dim, cnn_module_kernel-1)
+    cached_conv2 = init_state[num_encoders * 6 : num_encoders * 7]
+
+    build_inputs_outputs(cached_len, "cached_len", 1)
+    build_inputs_outputs(cached_avg, "cached_avg", 1)
+    build_inputs_outputs(cached_key, "cached_key", 2)
+    build_inputs_outputs(cached_val, "cached_val", 2)
+    build_inputs_outputs(cached_val2, "cached_val2", 2)
+    build_inputs_outputs(cached_conv1, "cached_conv1", 1)
+    build_inputs_outputs(cached_conv2, "cached_conv2", 1)
+
+    logging.info(inputs)
+    logging.info(outputs)
+    logging.info(input_names)
+    logging.info(output_names)
+
+    torch.onnx.export(
+        encoder_model,
+        (x, init_state),
+        encoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=input_names,
+        output_names=output_names,
+        dynamic_axes={
+            "x": {0: "N", 1: "T"},
+            "encoder_out": {0: "N", 1: "T"},
+            **inputs,
+            **outputs,
+        },
+    )
+
+    add_meta_data(filename=encoder_filename, meta_data=meta_data)
+
+
+def export_decoder_model_onnx(
+    decoder_model: nn.Module,
+    decoder_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the decoder model to ONNX format.
+
+    The exported model has one input:
+
+        - y: a torch.int64 tensor of shape (N, context_size)
+
+    and has one output:
+
+        - decoder_out: a torch.float32 tensor of shape (N, joiner_dim)
+
+    Note: The argument need_pad is fixed to False.
+
+    Args:
+      decoder_model:
+        The decoder model to be exported.
+      decoder_filename:
+        Filename to save the exported ONNX model.
+      opset_version:
+        The opset version to use.
+    """
+    context_size = decoder_model.decoder.context_size
+    vocab_size = decoder_model.decoder.vocab_size
+    y = torch.zeros(10, context_size, dtype=torch.int64)
+    torch.onnx.export(
+        decoder_model,
+        y,
+        decoder_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=["y"],
+        output_names=["decoder_out"],
+        dynamic_axes={
+            "y": {0: "N"},
+            "decoder_out": {0: "N"},
+        },
+    )
+    meta_data = {
+        "context_size": str(context_size),
+        "vocab_size": str(vocab_size),
+    }
+    add_meta_data(filename=decoder_filename, meta_data=meta_data)
+
+
+def export_joiner_model_onnx(
+    joiner_model: nn.Module,
+    joiner_filename: str,
+    opset_version: int = 11,
+) -> None:
+    """Export the joiner model to ONNX format.
+    The exported joiner model has two inputs:
+
+        - encoder_out: a tensor of shape (N, joiner_dim)
+        - decoder_out: a tensor of shape (N, joiner_dim)
+
+    and produces one output:
+
+        - logit: a tensor of shape (N, vocab_size)
+    """
+    joiner_dim = joiner_model.output_linear.weight.shape[1]
+    logging.info(f"joiner dim: {joiner_dim}")
+
+    projected_encoder_out = torch.rand(11, joiner_dim, dtype=torch.float32)
+    projected_decoder_out = torch.rand(11, joiner_dim, dtype=torch.float32)
+
+    torch.onnx.export(
+        joiner_model,
+        (projected_encoder_out, projected_decoder_out),
+        joiner_filename,
+        verbose=False,
+        opset_version=opset_version,
+        input_names=[
+            "encoder_out",
+            "decoder_out",
+        ],
+        output_names=["logit"],
+        dynamic_axes={
+            "encoder_out": {0: "N"},
+            "decoder_out": {0: "N"},
+            "logit": {0: "N"},
+        },
+    )
+    meta_data = {
+        "joiner_dim": str(joiner_dim),
+    }
+    add_meta_data(filename=joiner_filename, meta_data=meta_data)
+
+
+@torch.no_grad()
+def main():
+    args = get_parser().parse_args()
+    args.exp_dir = Path(args.exp_dir)
+
+    params = get_params()
+    params.update(vars(args))
+
+    device = torch.device("cpu")
+    if torch.cuda.is_available():
+        device = torch.device("cuda", 0)
+
+    setup_logger(f"{params.exp_dir}/log-export/log-export-onnx")
+
+    logging.info(f"device: {device}")
+
+    sp = spm.SentencePieceProcessor()
+    sp.load(params.bpe_model)
+
+    # <blk> is defined in local/train_bpe_model.py
+    params.blank_id = sp.piece_to_id("<blk>")
+    params.vocab_size = sp.get_piece_size()
+
+    logging.info(params)
+
+    logging.info("About to create model")
+    model = get_transducer_model(params)
+
+    model.to(device)
+
+    if not params.use_averaged_model:
+        if params.iter > 0:
+            filenames = find_checkpoints(params.exp_dir, iteration=-params.iter)[
+                : params.avg
+            ]
+            if len(filenames) == 0:
+                raise ValueError(
+                    f"No checkpoints found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            elif len(filenames) < params.avg:
+                raise ValueError(
+                    f"Not enough checkpoints ({len(filenames)}) found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            logging.info(f"averaging {filenames}")
+            model.to(device)
+            model.load_state_dict(average_checkpoints(filenames, device=device))
+        elif params.avg == 1:
+            load_checkpoint(f"{params.exp_dir}/epoch-{params.epoch}.pt", model)
+        else:
+            start = params.epoch - params.avg + 1
+            filenames = []
+            for i in range(start, params.epoch + 1):
+                if i >= 1:
+                    filenames.append(f"{params.exp_dir}/epoch-{i}.pt")
+            logging.info(f"averaging {filenames}")
+            model.to(device)
+            model.load_state_dict(average_checkpoints(filenames, device=device))
+    else:
+        if params.iter > 0:
+            filenames = find_checkpoints(params.exp_dir, iteration=-params.iter)[
+                : params.avg + 1
+            ]
+            if len(filenames) == 0:
+                raise ValueError(
+                    f"No checkpoints found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            elif len(filenames) < params.avg + 1:
+                raise ValueError(
+                    f"Not enough checkpoints ({len(filenames)}) found for"
+                    f" --iter {params.iter}, --avg {params.avg}"
+                )
+            filename_start = filenames[-1]
+            filename_end = filenames[0]
+            logging.info(
+                "Calculating the averaged model over iteration checkpoints"
+                f" from {filename_start} (excluded) to {filename_end}"
+            )
+            model.to(device)
+            model.load_state_dict(
+                average_checkpoints_with_averaged_model(
+                    filename_start=filename_start,
+                    filename_end=filename_end,
+                    device=device,
+                )
+            )
+        else:
+            assert params.avg > 0, params.avg
+            start = params.epoch - params.avg
+            assert start >= 1, start
+            filename_start = f"{params.exp_dir}/epoch-{start}.pt"
+            filename_end = f"{params.exp_dir}/epoch-{params.epoch}.pt"
+            logging.info(
+                f"Calculating the averaged model over epoch range from "
+                f"{start} (excluded) to {params.epoch}"
+            )
+            model.to(device)
+            model.load_state_dict(
+                average_checkpoints_with_averaged_model(
+                    filename_start=filename_start,
+                    filename_end=filename_end,
+                    device=device,
+                )
+            )
+
+    model.to("cpu")
+    model.eval()
+
+    convert_scaled_to_non_scaled(model, inplace=True)
+    encoder = OnnxEncoder(
+        encoder=model.encoder,
+        encoder_proj=model.joiner.encoder_proj,
+    )
+
+    decoder = OnnxDecoder(
+        decoder=model.decoder,
+        decoder_proj=model.joiner.decoder_proj,
+    )
+
+    joiner = OnnxJoiner(output_linear=model.joiner.output_linear)
+
+    encoder_num_param = sum([p.numel() for p in encoder.parameters()])
+    decoder_num_param = sum([p.numel() for p in decoder.parameters()])
+    joiner_num_param = sum([p.numel() for p in joiner.parameters()])
+    total_num_param = encoder_num_param + decoder_num_param + joiner_num_param
+    logging.info(f"encoder parameters: {encoder_num_param}")
+    logging.info(f"decoder parameters: {decoder_num_param}")
+    logging.info(f"joiner parameters: {joiner_num_param}")
+    logging.info(f"total parameters: {total_num_param}")
+
+    if params.iter > 0:
+        suffix = f"iter-{params.iter}"
+    else:
+        suffix = f"epoch-{params.epoch}"
+
+    suffix += f"-avg-{params.avg}"
+    if params.use_averaged_model:
+        suffix += "-with-averaged-model"
+
+    opset_version = 13
+
+    logging.info("Exporting encoder")
+    encoder_filename = params.exp_dir / f"encoder-{suffix}.onnx"
+    export_encoder_model_onnx(
+        encoder,
+        encoder_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported encoder to {encoder_filename}")
+
+    logging.info("Exporting decoder")
+    decoder_filename = params.exp_dir / f"decoder-{suffix}.onnx"
+    export_decoder_model_onnx(
+        decoder,
+        decoder_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported decoder to {decoder_filename}")
+
+    logging.info("Exporting joiner")
+    joiner_filename = params.exp_dir / f"joiner-{suffix}.onnx"
+    export_joiner_model_onnx(
+        joiner,
+        joiner_filename,
+        opset_version=opset_version,
+    )
+    logging.info(f"Exported joiner to {joiner_filename}")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_check.py b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_check.py
new file mode 100755
index 000000000..6c78ba70b
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_check.py
@@ -0,0 +1,261 @@
+#!/usr/bin/env python3
+#
+# Copyright 2023 Xiaomi Corporation (Author: Fangjun Kuang)
+
+"""
+This script checks that exported ONNX models produce the same output
+with the given torchscript model for the same input.
+
+We use the pre-trained model from
+https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+as an example to show how to use this file.
+
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained.pt"
+cd exp
+ln -s pretrained.pt epoch-99.pt
+popd
+
+2. Export the model via torch.jit.trace()
+
+./pruned_transducer_stateless7_streaming/jit_trace_export.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --use-averaged-model 0 \
+  --epoch 99 \
+  --avg 1 \
+  --decode-chunk-len 32 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files inside $repo/exp
+
+  - encoder_jit_trace.pt
+  - decoder_jit_trace.pt
+  - joiner_jit_trace.pt
+
+3. Export the model to ONNX
+
+./pruned_transducer_stateless7_streaming/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --use-averaged-model 0 \
+  --epoch 99 \
+  --avg 1 \
+  --decode-chunk-len 32 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files inside $repo/exp:
+
+  - encoder-epoch-99-avg-1.onnx
+  - decoder-epoch-99-avg-1.onnx
+  - joiner-epoch-99-avg-1.onnx
+
+4. Run this file
+
+./pruned_transducer_stateless7_streaming/onnx_check.py \
+  --jit-encoder-filename $repo/exp/encoder_jit_trace.pt \
+  --jit-decoder-filename $repo/exp/decoder_jit_trace.pt \
+  --jit-joiner-filename $repo/exp/joiner_jit_trace.pt \
+  --onnx-encoder-filename $repo/exp/encoder-epoch-99-avg-1.onnx \
+  --onnx-decoder-filename $repo/exp/decoder-epoch-99-avg-1.onnx \
+  --onnx-joiner-filename $repo/exp/joiner-epoch-99-avg-1.onnx
+"""
+
+import argparse
+import logging
+
+from onnx_pretrained import OnnxModel
+from zipformer import stack_states
+
+from icefall import is_module_available
+
+import torch
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--jit-encoder-filename",
+        required=True,
+        type=str,
+        help="Path to the torchscript encoder model",
+    )
+
+    parser.add_argument(
+        "--jit-decoder-filename",
+        required=True,
+        type=str,
+        help="Path to the torchscript decoder model",
+    )
+
+    parser.add_argument(
+        "--jit-joiner-filename",
+        required=True,
+        type=str,
+        help="Path to the torchscript joiner model",
+    )
+
+    parser.add_argument(
+        "--onnx-encoder-filename",
+        required=True,
+        type=str,
+        help="Path to the ONNX encoder model",
+    )
+
+    parser.add_argument(
+        "--onnx-decoder-filename",
+        required=True,
+        type=str,
+        help="Path to the ONNX decoder model",
+    )
+
+    parser.add_argument(
+        "--onnx-joiner-filename",
+        required=True,
+        type=str,
+        help="Path to the ONNX joiner model",
+    )
+
+    return parser
+
+
+def test_encoder(
+    torch_encoder_model: torch.jit.ScriptModule,
+    torch_encoder_proj_model: torch.jit.ScriptModule,
+    onnx_model: OnnxModel,
+):
+    N = torch.randint(1, 100, size=(1,)).item()
+    T = onnx_model.segment
+    C = 80
+    x_lens = torch.tensor([T] * N)
+    torch_states = [torch_encoder_model.get_init_state() for _ in range(N)]
+    torch_states = stack_states(torch_states)
+
+    onnx_model.init_encoder_states(N)
+
+    for i in range(5):
+        logging.info(f"test_encoder: iter {i}")
+        x = torch.rand(N, T, C)
+        torch_encoder_out, _, torch_states = torch_encoder_model(
+            x, x_lens, torch_states
+        )
+        torch_encoder_out = torch_encoder_proj_model(torch_encoder_out)
+
+        onnx_encoder_out = onnx_model.run_encoder(x)
+
+        assert torch.allclose(torch_encoder_out, onnx_encoder_out, atol=1e-4), (
+            (torch_encoder_out - onnx_encoder_out).abs().max()
+        )
+
+
+def test_decoder(
+    torch_decoder_model: torch.jit.ScriptModule,
+    torch_decoder_proj_model: torch.jit.ScriptModule,
+    onnx_model: OnnxModel,
+):
+    context_size = onnx_model.context_size
+    vocab_size = onnx_model.vocab_size
+    for i in range(10):
+        N = torch.randint(1, 100, size=(1,)).item()
+        logging.info(f"test_decoder: iter {i}, N={N}")
+        x = torch.randint(
+            low=1,
+            high=vocab_size,
+            size=(N, context_size),
+            dtype=torch.int64,
+        )
+        torch_decoder_out = torch_decoder_model(x, need_pad=torch.tensor([False]))
+        torch_decoder_out = torch_decoder_proj_model(torch_decoder_out)
+        torch_decoder_out = torch_decoder_out.squeeze(1)
+
+        onnx_decoder_out = onnx_model.run_decoder(x)
+        assert torch.allclose(torch_decoder_out, onnx_decoder_out, atol=1e-4), (
+            (torch_decoder_out - onnx_decoder_out).abs().max()
+        )
+
+
+def test_joiner(
+    torch_joiner_model: torch.jit.ScriptModule,
+    onnx_model: OnnxModel,
+):
+    encoder_dim = torch_joiner_model.encoder_proj.weight.shape[1]
+    decoder_dim = torch_joiner_model.decoder_proj.weight.shape[1]
+    for i in range(10):
+        N = torch.randint(1, 100, size=(1,)).item()
+        logging.info(f"test_joiner: iter {i}, N={N}")
+        encoder_out = torch.rand(N, encoder_dim)
+        decoder_out = torch.rand(N, decoder_dim)
+
+        projected_encoder_out = torch_joiner_model.encoder_proj(encoder_out)
+        projected_decoder_out = torch_joiner_model.decoder_proj(decoder_out)
+
+        torch_joiner_out = torch_joiner_model(encoder_out, decoder_out)
+        onnx_joiner_out = onnx_model.run_joiner(
+            projected_encoder_out, projected_decoder_out
+        )
+
+        assert torch.allclose(torch_joiner_out, onnx_joiner_out, atol=1e-4), (
+            (torch_joiner_out - onnx_joiner_out).abs().max()
+        )
+
+
+@torch.no_grad()
+def main():
+    args = get_parser().parse_args()
+    logging.info(vars(args))
+
+    torch_encoder_model = torch.jit.load(args.jit_encoder_filename)
+    torch_decoder_model = torch.jit.load(args.jit_decoder_filename)
+    torch_joiner_model = torch.jit.load(args.jit_joiner_filename)
+
+    onnx_model = OnnxModel(
+        encoder_model_filename=args.onnx_encoder_filename,
+        decoder_model_filename=args.onnx_decoder_filename,
+        joiner_model_filename=args.onnx_joiner_filename,
+    )
+
+    logging.info("Test encoder")
+    # When exporting the model to onnx, we have already put the encoder_proj
+    # inside the encoder.
+    test_encoder(torch_encoder_model, torch_joiner_model.encoder_proj, onnx_model)
+
+    logging.info("Test decoder")
+    # When exporting the model to onnx, we have already put the decoder_proj
+    # inside the decoder.
+    test_decoder(torch_decoder_model, torch_joiner_model.decoder_proj, onnx_model)
+
+    logging.info("Test joiner")
+    test_joiner(torch_joiner_model, onnx_model)
+
+    logging.info("Finished checking ONNX models")
+
+
+torch.set_num_threads(1)
+torch.set_num_interop_threads(1)
+
+# See https://github.com/pytorch/pytorch/issues/38342
+# and https://github.com/pytorch/pytorch/issues/33354
+#
+# If we don't do this, the delay increases whenever there is
+# a new request that changes the actual batch size.
+# If you use `py-spy dump --pid <server-pid> --native`, you will
+# see a lot of time is spent in re-compiling the torch script model.
+torch._C._jit_set_profiling_executor(False)
+torch._C._jit_set_profiling_mode(False)
+torch._C._set_graph_executor_optimize(False)
+if __name__ == "__main__":
+    torch.manual_seed(20230207)
+    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
+
+    logging.basicConfig(format=formatter, level=logging.INFO)
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_model_wrapper.py b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_model_wrapper.py
index f52deecc9..71a418742 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_model_wrapper.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_model_wrapper.py
@@ -12,7 +12,7 @@ class OnnxStreamingEncoder(torch.nn.Module):
     def __init__(self, encoder):
         """
         Args:
-            encoder: A Instance of Zipformer Class
+            encoder: An instance of Zipformer Class
         """
         super().__init__()
         self.model = encoder
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_pretrained.py b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_pretrained.py
new file mode 100755
index 000000000..715560c70
--- /dev/null
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/onnx_pretrained.py
@@ -0,0 +1,509 @@
+#!/usr/bin/env python3
+# Copyright      2023  Xiaomi Corp.        (authors: Fangjun Kuang)
+
+"""
+This script loads ONNX models exported by ./export-onnx.py
+and uses them to decode waves.
+
+We use the pre-trained model from
+https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+as an example to show how to use this file.
+
+1. Download the pre-trained model
+
+cd egs/librispeech/ASR
+
+repo_url=https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless7-streaming-2022-12-29
+GIT_LFS_SKIP_SMUDGE=1 git clone $repo_url
+repo=$(basename $repo_url)
+
+pushd $repo
+git lfs pull --include "data/lang_bpe_500/bpe.model"
+git lfs pull --include "exp/pretrained.pt"
+cd exp
+ln -s pretrained.pt epoch-99.pt
+popd
+
+2. Export the model to ONNX
+
+./pruned_transducer_stateless7_streaming/export-onnx.py \
+  --bpe-model $repo/data/lang_bpe_500/bpe.model \
+  --use-averaged-model 0 \
+  --epoch 99 \
+  --avg 1 \
+  --decode-chunk-len 32 \
+  --exp-dir $repo/exp/
+
+It will generate the following 3 files in $repo/exp
+
+  - encoder-epoch-99-avg-1.onnx
+  - decoder-epoch-99-avg-1.onnx
+  - joiner-epoch-99-avg-1.onnx
+
+3. Run this file with the exported ONNX models
+
+./pruned_transducer_stateless7_streaming/onnx_pretrained.py \
+  --encoder-model-filename $repo/exp/encoder-epoch-99-avg-1.onnx \
+  --decoder-model-filename $repo/exp/decoder-epoch-99-avg-1.onnx \
+  --joiner-model-filename $repo/exp/joiner-epoch-99-avg-1.onnx \
+  --tokens $repo/data/lang_bpe_500/tokens.txt \
+  $repo/test_wavs/1089-134686-0001.wav
+
+Note: Even though this script only supports decoding a single file,
+the exported ONNX models do support batch processing.
+"""
+
+import argparse
+import logging
+from typing import Dict, List, Optional, Tuple
+
+import k2
+import numpy as np
+import onnxruntime as ort
+import torch
+import torchaudio
+from kaldifeat import FbankOptions, OnlineFbank, OnlineFeature
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--encoder-model-filename",
+        type=str,
+        required=True,
+        help="Path to the encoder onnx model. ",
+    )
+
+    parser.add_argument(
+        "--decoder-model-filename",
+        type=str,
+        required=True,
+        help="Path to the decoder onnx model. ",
+    )
+
+    parser.add_argument(
+        "--joiner-model-filename",
+        type=str,
+        required=True,
+        help="Path to the joiner onnx model. ",
+    )
+
+    parser.add_argument(
+        "--tokens",
+        type=str,
+        help="""Path to tokens.txt.""",
+    )
+
+    parser.add_argument(
+        "sound_file",
+        type=str,
+        help="The input sound file to transcribe. "
+        "Supported formats are those supported by torchaudio.load(). "
+        "For example, wav and flac are supported. "
+        "The sample rate has to be 16kHz.",
+    )
+
+    return parser
+
+
+class OnnxModel:
+    def __init__(
+        self,
+        encoder_model_filename: str,
+        decoder_model_filename: str,
+        joiner_model_filename: str,
+    ):
+        session_opts = ort.SessionOptions()
+        session_opts.inter_op_num_threads = 1
+        session_opts.intra_op_num_threads = 1
+
+        self.session_opts = session_opts
+
+        self.init_encoder(encoder_model_filename)
+        self.init_decoder(decoder_model_filename)
+        self.init_joiner(joiner_model_filename)
+
+    def init_encoder(self, encoder_model_filename: str):
+        self.encoder = ort.InferenceSession(
+            encoder_model_filename,
+            sess_options=self.session_opts,
+        )
+        self.init_encoder_states()
+
+    def init_encoder_states(self, batch_size: int = 1):
+        encoder_meta = self.encoder.get_modelmeta().custom_metadata_map
+
+        decode_chunk_len = int(encoder_meta["decode_chunk_len"])
+        pad_length = int(encoder_meta["pad_length"])
+
+        num_encoder_layers = encoder_meta["num_encoder_layers"]
+        encoder_dims = encoder_meta["encoder_dims"]
+        attention_dims = encoder_meta["attention_dims"]
+        cnn_module_kernels = encoder_meta["cnn_module_kernels"]
+        left_context_len = encoder_meta["left_context_len"]
+
+        def to_int_list(s):
+            return list(map(int, s.split(",")))
+
+        num_encoder_layers = to_int_list(num_encoder_layers)
+        encoder_dims = to_int_list(encoder_dims)
+        attention_dims = to_int_list(attention_dims)
+        cnn_module_kernels = to_int_list(cnn_module_kernels)
+        left_context_len = to_int_list(left_context_len)
+
+        logging.info(f"decode_chunk_len: {decode_chunk_len}")
+        logging.info(f"pad_length: {pad_length}")
+        logging.info(f"num_encoder_layers: {num_encoder_layers}")
+        logging.info(f"encoder_dims: {encoder_dims}")
+        logging.info(f"attention_dims: {attention_dims}")
+        logging.info(f"cnn_module_kernels: {cnn_module_kernels}")
+        logging.info(f"left_context_len: {left_context_len}")
+
+        num_encoders = len(num_encoder_layers)
+
+        cached_len = []
+        cached_avg = []
+        cached_key = []
+        cached_val = []
+        cached_val2 = []
+        cached_conv1 = []
+        cached_conv2 = []
+
+        N = batch_size
+
+        for i in range(num_encoders):
+            cached_len.append(torch.zeros(num_encoder_layers[i], N, dtype=torch.int64))
+            cached_avg.append(torch.zeros(num_encoder_layers[i], N, encoder_dims[i]))
+            cached_key.append(
+                torch.zeros(
+                    num_encoder_layers[i], left_context_len[i], N, attention_dims[i]
+                )
+            )
+            cached_val.append(
+                torch.zeros(
+                    num_encoder_layers[i],
+                    left_context_len[i],
+                    N,
+                    attention_dims[i] // 2,
+                )
+            )
+            cached_val2.append(
+                torch.zeros(
+                    num_encoder_layers[i],
+                    left_context_len[i],
+                    N,
+                    attention_dims[i] // 2,
+                )
+            )
+            cached_conv1.append(
+                torch.zeros(
+                    num_encoder_layers[i], N, encoder_dims[i], cnn_module_kernels[i] - 1
+                )
+            )
+            cached_conv2.append(
+                torch.zeros(
+                    num_encoder_layers[i], N, encoder_dims[i], cnn_module_kernels[i] - 1
+                )
+            )
+
+        self.cached_len = cached_len
+        self.cached_avg = cached_avg
+        self.cached_key = cached_key
+        self.cached_val = cached_val
+        self.cached_val2 = cached_val2
+        self.cached_conv1 = cached_conv1
+        self.cached_conv2 = cached_conv2
+
+        self.num_encoders = num_encoders
+
+        self.segment = decode_chunk_len + pad_length
+        self.offset = decode_chunk_len
+
+    def init_decoder(self, decoder_model_filename: str):
+        self.decoder = ort.InferenceSession(
+            decoder_model_filename,
+            sess_options=self.session_opts,
+        )
+
+        decoder_meta = self.decoder.get_modelmeta().custom_metadata_map
+        self.context_size = int(decoder_meta["context_size"])
+        self.vocab_size = int(decoder_meta["vocab_size"])
+
+        logging.info(f"context_size: {self.context_size}")
+        logging.info(f"vocab_size: {self.vocab_size}")
+
+    def init_joiner(self, joiner_model_filename: str):
+        self.joiner = ort.InferenceSession(
+            joiner_model_filename,
+            sess_options=self.session_opts,
+        )
+
+        joiner_meta = self.joiner.get_modelmeta().custom_metadata_map
+        self.joiner_dim = int(joiner_meta["joiner_dim"])
+
+        logging.info(f"joiner_dim: {self.joiner_dim}")
+
+    def _build_encoder_input_output(
+        self,
+        x: torch.Tensor,
+    ) -> Tuple[Dict[str, np.ndarray], List[str]]:
+        encoder_input = {"x": x.numpy()}
+        encoder_output = ["encoder_out"]
+
+        def build_states_input(states: List[torch.Tensor], name: str):
+            for i, s in enumerate(states):
+                if isinstance(s, torch.Tensor):
+                    encoder_input[f"{name}_{i}"] = s.numpy()
+                else:
+                    encoder_input[f"{name}_{i}"] = s
+
+                encoder_output.append(f"new_{name}_{i}")
+
+        build_states_input(self.cached_len, "cached_len")
+        build_states_input(self.cached_avg, "cached_avg")
+        build_states_input(self.cached_key, "cached_key")
+        build_states_input(self.cached_val, "cached_val")
+        build_states_input(self.cached_val2, "cached_val2")
+        build_states_input(self.cached_conv1, "cached_conv1")
+        build_states_input(self.cached_conv2, "cached_conv2")
+
+        return encoder_input, encoder_output
+
+    def _update_states(self, states: List[np.ndarray]):
+        num_encoders = self.num_encoders
+
+        self.cached_len = states[num_encoders * 0 : num_encoders * 1]
+        self.cached_avg = states[num_encoders * 1 : num_encoders * 2]
+        self.cached_key = states[num_encoders * 2 : num_encoders * 3]
+        self.cached_val = states[num_encoders * 3 : num_encoders * 4]
+        self.cached_val2 = states[num_encoders * 4 : num_encoders * 5]
+        self.cached_conv1 = states[num_encoders * 5 : num_encoders * 6]
+        self.cached_conv2 = states[num_encoders * 6 : num_encoders * 7]
+
+    def run_encoder(self, x: torch.Tensor) -> torch.Tensor:
+        """
+        Args:
+          x:
+            A 3-D tensor of shape (N, T, C)
+        Returns:
+          Return a 3-D tensor of shape (N, T', joiner_dim) where
+          T' is usually equal to ((T-7)//2+1)//2
+        """
+        encoder_input, encoder_output_names = self._build_encoder_input_output(x)
+        out = self.encoder.run(encoder_output_names, encoder_input)
+
+        self._update_states(out[1:])
+
+        return torch.from_numpy(out[0])
+
+    def run_decoder(self, decoder_input: torch.Tensor) -> torch.Tensor:
+        """
+        Args:
+          decoder_input:
+            A 2-D tensor of shape (N, context_size)
+        Returns:
+          Return a 2-D tensor of shape (N, joiner_dim)
+        """
+        out = self.decoder.run(
+            [self.decoder.get_outputs()[0].name],
+            {self.decoder.get_inputs()[0].name: decoder_input.numpy()},
+        )[0]
+
+        return torch.from_numpy(out)
+
+    def run_joiner(
+        self, encoder_out: torch.Tensor, decoder_out: torch.Tensor
+    ) -> torch.Tensor:
+        """
+        Args:
+          encoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+          decoder_out:
+            A 2-D tensor of shape (N, joiner_dim)
+        Returns:
+          Return a 2-D tensor of shape (N, vocab_size)
+        """
+        out = self.joiner.run(
+            [self.joiner.get_outputs()[0].name],
+            {
+                self.joiner.get_inputs()[0].name: encoder_out.numpy(),
+                self.joiner.get_inputs()[1].name: decoder_out.numpy(),
+            },
+        )[0]
+
+        return torch.from_numpy(out)
+
+
+def read_sound_files(
+    filenames: List[str], expected_sample_rate: float
+) -> List[torch.Tensor]:
+    """Read a list of sound files into a list 1-D float32 torch tensors.
+    Args:
+      filenames:
+        A list of sound filenames.
+      expected_sample_rate:
+        The expected sample rate of the sound files.
+    Returns:
+      Return a list of 1-D float32 torch tensors.
+    """
+    ans = []
+    for f in filenames:
+        wave, sample_rate = torchaudio.load(f)
+        assert (
+            sample_rate == expected_sample_rate
+        ), f"expected sample rate: {expected_sample_rate}. Given: {sample_rate}"
+        # We use only the first channel
+        ans.append(wave[0].contiguous())
+    return ans
+
+
+def create_streaming_feature_extractor() -> OnlineFeature:
+    """Create a CPU streaming feature extractor.
+
+    At present, we assume it returns a fbank feature extractor with
+    fixed options. In the future, we will support passing in the options
+    from outside.
+
+    Returns:
+      Return a CPU streaming feature extractor.
+    """
+    opts = FbankOptions()
+    opts.device = "cpu"
+    opts.frame_opts.dither = 0
+    opts.frame_opts.snip_edges = False
+    opts.frame_opts.samp_freq = 16000
+    opts.mel_opts.num_bins = 80
+    return OnlineFbank(opts)
+
+
+def greedy_search(
+    model: OnnxModel,
+    encoder_out: torch.Tensor,
+    context_size: int,
+    decoder_out: Optional[torch.Tensor] = None,
+    hyp: Optional[List[int]] = None,
+) -> List[int]:
+    """Greedy search in batch mode. It hardcodes --max-sym-per-frame=1.
+    Args:
+      model:
+        The transducer model.
+      encoder_out:
+        A 3-D tensor of shape (1, T, joiner_dim)
+      context_size:
+        The context size of the decoder model.
+      decoder_out:
+        Optional. Decoder output of the previous chunk.
+      hyp:
+        Decoding results for previous chunks.
+    Returns:
+      Return the decoded results so far.
+    """
+
+    blank_id = 0
+
+    if decoder_out is None:
+        assert hyp is None, hyp
+        hyp = [blank_id] * context_size
+        decoder_input = torch.tensor([hyp], dtype=torch.int64)
+        decoder_out = model.run_decoder(decoder_input)
+    else:
+        assert hyp is not None, hyp
+
+    encoder_out = encoder_out.squeeze(0)
+    T = encoder_out.size(0)
+    for t in range(T):
+        cur_encoder_out = encoder_out[t : t + 1]
+        joiner_out = model.run_joiner(cur_encoder_out, decoder_out).squeeze(0)
+        y = joiner_out.argmax(dim=0).item()
+        if y != blank_id:
+            hyp.append(y)
+            decoder_input = hyp[-context_size:]
+            decoder_input = torch.tensor([decoder_input], dtype=torch.int64)
+            decoder_out = model.run_decoder(decoder_input)
+
+    return hyp, decoder_out
+
+
+@torch.no_grad()
+def main():
+    parser = get_parser()
+    args = parser.parse_args()
+    logging.info(vars(args))
+
+    model = OnnxModel(
+        encoder_model_filename=args.encoder_model_filename,
+        decoder_model_filename=args.decoder_model_filename,
+        joiner_model_filename=args.joiner_model_filename,
+    )
+
+    sample_rate = 16000
+
+    logging.info("Constructing Fbank computer")
+    online_fbank = create_streaming_feature_extractor()
+
+    logging.info(f"Reading sound files: {args.sound_file}")
+    waves = read_sound_files(
+        filenames=[args.sound_file],
+        expected_sample_rate=sample_rate,
+    )[0]
+
+    tail_padding = torch.zeros(int(0.3 * sample_rate), dtype=torch.float32)
+    wave_samples = torch.cat([waves, tail_padding])
+
+    num_processed_frames = 0
+    segment = model.segment
+    offset = model.offset
+
+    context_size = model.context_size
+    hyp = None
+    decoder_out = None
+
+    chunk = int(1 * sample_rate)  # 1 second
+    start = 0
+    while start < wave_samples.numel():
+        end = min(start + chunk, wave_samples.numel())
+        samples = wave_samples[start:end]
+        start += chunk
+
+        online_fbank.accept_waveform(
+            sampling_rate=sample_rate,
+            waveform=samples,
+        )
+
+        while online_fbank.num_frames_ready - num_processed_frames >= segment:
+            frames = []
+            for i in range(segment):
+                frames.append(online_fbank.get_frame(num_processed_frames + i))
+            num_processed_frames += offset
+            frames = torch.cat(frames, dim=0)
+            frames = frames.unsqueeze(0)
+            encoder_out = model.run_encoder(frames)
+            hyp, decoder_out = greedy_search(
+                model,
+                encoder_out,
+                context_size,
+                decoder_out,
+                hyp,
+            )
+
+    symbol_table = k2.SymbolTable.from_file(args.tokens)
+
+    text = ""
+    for i in hyp[context_size:]:
+        text += symbol_table[i]
+    text = text.replace("▁", " ").strip()
+
+    logging.info(args.sound_file)
+    logging.info(text)
+
+    logging.info("Decoding Done")
+
+
+if __name__ == "__main__":
+    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
+
+    logging.basicConfig(format=formatter, level=logging.INFO)
+    main()
diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/zipformer.py b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/zipformer.py
index 1b267c1c5..f7e52a9e6 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/zipformer.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7_streaming/zipformer.py
@@ -270,7 +270,7 @@ class Zipformer(EncoderInterface):
         dim_feedforward (int, int): feedforward dimension in 2 encoder stacks
         num_encoder_layers (int): number of encoder layers
         dropout (float): dropout rate
-        cnn_module_kernel (int): Kernel size of convolution module
+        cnn_module_kernels (int): Kernel size of convolution module
         vgg_frontend (bool): whether to use vgg frontend.
         warmup_batches (float): number of batches to warm up over
     """
@@ -311,6 +311,8 @@ class Zipformer(EncoderInterface):
         # Used in decoding
         self.decode_chunk_size = decode_chunk_size
 
+        self.left_context_len = self.decode_chunk_size * self.num_left_chunks
+
         # will be written to, see set_batch_count()
         self.batch_count = 0
         self.warmup_end = warmup_batches
@@ -330,7 +332,10 @@ class Zipformer(EncoderInterface):
         # each one will be ZipformerEncoder or DownsampledZipformerEncoder
         encoders = []
 
+        self.num_encoder_layers = num_encoder_layers
         self.num_encoders = len(encoder_dims)
+        self.attention_dims = attention_dim
+        self.cnn_module_kernels = cnn_module_kernels
         for i in range(self.num_encoders):
             encoder_layer = ZipformerEncoderLayer(
                 encoder_dims[i],
@@ -382,7 +387,7 @@ class Zipformer(EncoderInterface):
 
     def _init_skip_modules(self):
         """
-        If self.zipformer_downampling_factors = (1, 2, 4, 8, 4, 2), then at the input of layer
+        If self.zipformer_downsampling_factors = (1, 2, 4, 8, 4, 2), then at the input of layer
         indexed 4 (in zero indexing), with has subsapling_factor=4, we combine the output of
         layers 2 and 3; and at the input of layer indexed 5, which which has subsampling_factor=2,
         we combine the outputs of layers 1 and 5.
@@ -695,7 +700,7 @@ class Zipformer(EncoderInterface):
             num_layers = encoder.num_layers
             ds = self.zipformer_downsampling_factors[i]
 
-            len_avg = torch.zeros(num_layers, 1, dtype=torch.int32, device=device)
+            len_avg = torch.zeros(num_layers, 1, dtype=torch.int64, device=device)
             cached_len.append(len_avg)
 
             avg = torch.zeros(num_layers, 1, encoder.d_model, device=device)