icefall/egs/librispeech/ASR/RESULTS.md

Results

pruned_transducer_stateless8 (zipformer + multidataset)

See https://github.com/k2-fsa/icefall/pull/675 for more details.

pruned_transducer_stateless8

The tensorboard log can be found at https://tensorboard.dev/experiment/y6kAPnN3S3OwvQxQqKQzsQ

You can find a pretrained model, training logs, decoding logs, and decoding results at: https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless8-2022-11-14

You can use https://github.com/k2-fsa/sherpa to deploy it.

Number of model parameters: 70369391, i.e., 70.37 M

	test-clean	test-other	comment
greedy search	1.87	4.38	--epoch 16 --avg 2 --max-duration 600
modified beam search	1.81	4.34	--epoch 16 --avg 2 --max-duration 600
fast beam search	1.91	4.33	--epoch 16 --avg 2 --max-duration 600

The training commands are:

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./pruned_transducer_stateless8/train.py \
  --world-size 8 \
  --num-epochs 20 \
  --full-libri 1 \
  --use-fp16 1 \
  --max-duration 750 \
  --exp-dir pruned_transducer_stateless8/exp \
  --feedforward-dims  "1024,1024,2048,2048,1024" \
  --master-port 12535 \
  --giga-prob 0.9

The decoding commands are:

for m in greedy_search fast_beam_search modified_beam_search ; do
  for epoch in 16; do
    for avg in 2; do
      ./pruned_transducer_stateless8/decode.py \
          --epoch $epoch \
          --avg $avg \
          --use-averaged-model 1 \
          --exp-dir ./pruned_transducer_stateless8/exp \
          --feedforward-dims  "1024,1024,2048,2048,1024" \
          --max-duration 600 \
          --decoding-method $m
    done
  done
done

pruned_transducer_stateless7 (zipformer)

See https://github.com/k2-fsa/icefall/pull/672 for more details.

pruned_transducer_stateless7

The tensorboard log can be found at https://tensorboard.dev/experiment/P7vXWqK7QVu1mU9Ene1gGg/

You can find a pretrained model, training logs, decoding logs, and decoding results at: https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless7-2022-11-11

You can use https://github.com/k2-fsa/sherpa to deploy it.

Number of model parameters: 70369391, i.e., 70.37 M

	test-clean	test-other	comment
greedy search	2.17	5.23	--epoch 39 --avg 6 --max-duration 600
modified beam search	2.15	5.20	--epoch 39 --avg 6 --max-duration 600
fast beam search	2.15	5.22	--epoch 39 --avg 6 --max-duration 600

The training commands are:

export CUDA_VISIBLE_DEVICES="0,3,6,7"

./pruned_transducer_stateless7/train.py \
  --world-size 4 \
  --num-epochs 30 \
  --full-libri 1 \
  --use-fp16 1 \
  --max-duration 750 \
  --exp-dir pruned_transducer_stateless7/exp \
  --feedforward-dims  "1024,1024,2048,2048,1024" \
  --master-port 12535

The decoding commands are:

for m in greedy_search fast_beam_search modified_beam_search ; do
  for epoch in 30; do
    for avg in 9; do
      ./pruned_transducer_stateless7/decode.py \
          --epoch $epoch \
          --avg $avg \
          --use-averaged-model 1 \
          --exp-dir ./pruned_transducer_stateless7/exp \
          --feedforward-dims  "1024,1024,2048,2048,1024" \
          --max-duration 600 \
          --decoding-method $m
    done
  done
done

LibriSpeech BPE training results (Pruned Stateless LSTM RNN-T + gradient filter)

lstm_transducer_stateless3

It implements LSTM model with mechanisms in reworked model for streaming ASR. Gradient filter is applied inside each lstm module to stabilize the training.

See https://github.com/k2-fsa/icefall/pull/564 for more details.

training on full librispeech

This model contains 12 encoder layers (LSTM module + Feedforward module). The number of model parameters is 84689496.

The WERs are:

	test-clean	test-other	comment	decoding mode
greedy search (max sym per frame 1)	3.66	9.51	--epoch 40 --avg 15	simulated streaming
greedy search (max sym per frame 1)	3.66	9.48	--epoch 40 --avg 15	streaming
fast beam search	3.55	9.33	--epoch 40 --avg 15	simulated streaming
fast beam search	3.57	9.25	--epoch 40 --avg 15	streaming
modified beam search	3.55	9.28	--epoch 40 --avg 15	simulated streaming
modified beam search	3.54	9.25	--epoch 40 --avg 15	streaming

Note: simulated streaming indicates feeding full utterance during decoding, while streaming indicates feeding certain number of frames at each time.

The training command is:

./lstm_transducer_stateless3/train.py \
  --world-size 4 \
  --num-epochs 40 \
  --start-epoch 1 \
  --exp-dir lstm_transducer_stateless3/exp \
  --full-libri 1 \
  --max-duration 500 \
  --master-port 12325 \
  --num-encoder-layers 12 \
  --grad-norm-threshold 25.0 \
  --rnn-hidden-size 1024

The tensorboard log can be found at https://tensorboard.dev/experiment/caNPyr5lT8qAl9qKsXEeEQ/

The simulated streaming decoding command using greedy search, fast beam search, and modified beam search is:

for decoding_method in greedy_search fast_beam_search modified_beam_search; do
  ./lstm_transducer_stateless3/decode.py \
    --epoch 40 \
    --avg 15 \
    --exp-dir lstm_transducer_stateless3/exp \
    --max-duration 600 \
    --num-encoder-layers 12 \
    --rnn-hidden-size 1024 \
    --decoding-method $decoding_method \
    --use-averaged-model True \
    --beam 4 \
    --max-contexts 4 \
    --max-states 8 \
    --beam-size 4
done

The streaming decoding command using greedy search, fast beam search, and modified beam search is:

for decoding_method in greedy_search fast_beam_search modified_beam_search; do
  ./lstm_transducer_stateless3/streaming_decode.py \
    --epoch 40 \
    --avg 15 \
    --exp-dir lstm_transducer_stateless3/exp \
    --max-duration 600 \
    --num-encoder-layers 12 \
    --rnn-hidden-size 1024 \
    --decoding-method $decoding_method \
    --use-averaged-model True \
    --beam 4 \
    --max-contexts 4 \
    --max-states 8 \
    --beam-size 4
done

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/Zengwei/icefall-asr-librispeech-lstm-transducer-stateless3-2022-09-28

LibriSpeech BPE training results (Pruned Stateless LSTM RNN-T + multi-dataset)

lstm_transducer_stateless2

See https://github.com/k2-fsa/icefall/pull/558 for more details.

The WERs are:

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.78	7.36	--iter 468000 --avg 16
modified_beam_search	2.73	7.15	--iter 468000 --avg 16
modified_beam_search + RNNLM shallow fusion	2.42	6.46	--iter 468000 --avg 16
fast_beam_search	2.76	7.31	--iter 468000 --avg 16
greedy search (max sym per frame 1)	2.77	7.35	--iter 472000 --avg 18
modified_beam_search	2.75	7.08	--iter 472000 --avg 18
fast_beam_search	2.77	7.29	--iter 472000 --avg 18

The training command is:

#!/usr/bin/env bash

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./lstm_transducer_stateless2/train.py \
  --world-size 8 \
  --num-epochs 35 \
  --start-epoch 1 \
  --full-libri 1 \
  --exp-dir lstm_transducer_stateless2/exp \
  --max-duration 500 \
  --use-fp16 0 \
  --lr-epochs 10 \
  --num-workers 2 \
  --giga-prob 0.9

Note: It was killed manually after getting epoch-18.pt. Also, we resumed training after getting epoch-9.pt.

The tensorboard log can be found at https://tensorboard.dev/experiment/1ziQ2LFmQY2mt4dlUr5dyA/

The decoding command is

for m in greedy_search fast_beam_search modified_beam_search; do
  for iter in 472000; do
    for avg in 8 10 12 14 16 18; do
      ./lstm_transducer_stateless2/decode.py \
        --iter $iter \
        --avg $avg \
        --exp-dir lstm_transducer_stateless2/exp \
        --max-duration 600 \
        --num-encoder-layers 12 \
        --rnn-hidden-size 1024 \
        --decoding-method $m \
        --use-averaged-model True \
        --beam 4 \
        --max-contexts 4 \
        --max-states 8 \
        --beam-size 4
    done
  done
done

To decode with RNNLM shallow fusion, use the following decoding command. A well-trained RNNLM can be found here: https://huggingface.co/ezerhouni/icefall-librispeech-rnn-lm/tree/main

for iter in 472000; do for avg in 8 10 12 14 16 18; do ./lstm_transducer_stateless2/decode.py
--iter $iter
--avg $avg
--exp-dir ./lstm_transducer_stateless2/exp
--max-duration 600
--decoding-method modified_beam_search_rnnlm_shallow_fusion
--beam 4
--rnn-lm-scale 0.3
--rnn-lm-exp-dir /path/to/RNNLM
--rnn-lm-epoch 99
--rnn-lm-avg 1
--rnn-lm-num-layers 3
--rnn-lm-tie-weights 1 done done

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/csukuangfj/icefall-asr-librispeech-lstm-transducer-stateless2-2022-09-03

LibriSpeech BPE training results (Pruned Stateless LSTM RNN-T)

lstm_transducer_stateless

It implements LSTM model with mechanisms in reworked model for streaming ASR.

See https://github.com/k2-fsa/icefall/pull/479 for more details.

training on full librispeech

This model contains 12 encoder layers (LSTM module + Feedforward module). The number of model parameters is 84689496.

The WERs are:

	test-clean	test-other	comment	decoding mode
greedy search (max sym per frame 1)	3.81	9.73	--epoch 35 --avg 15	simulated streaming
greedy search (max sym per frame 1)	3.78	9.79	--epoch 35 --avg 15	streaming
fast beam search	3.74	9.59	--epoch 35 --avg 15	simulated streaming
fast beam search	3.73	9.61	--epoch 35 --avg 15	streaming
modified beam search	3.64	9.55	--epoch 35 --avg 15	simulated streaming
modified beam search	3.65	9.51	--epoch 35 --avg 15	streaming

Note: simulated streaming indicates feeding full utterance during decoding, while streaming indicates feeding certain number of frames at each time.

The training command is:

./lstm_transducer_stateless/train.py \
  --world-size 4 \
  --num-epochs 35 \
  --start-epoch 1 \
  --exp-dir lstm_transducer_stateless/exp \
  --full-libri 1 \
  --max-duration 500 \
  --master-port 12321 \
  --num-encoder-layers 12 \
  --rnn-hidden-size 1024

The tensorboard log can be found at https://tensorboard.dev/experiment/FWrM20mjTeWo6dTpFYOsYQ/

The simulated streaming decoding command using greedy search, fast beam search, and modified beam search is:

for decoding_method in greedy_search fast_beam_search modified_beam_search; do
  ./lstm_transducer_stateless/decode.py \
    --epoch 35 \
    --avg 15 \
    --exp-dir lstm_transducer_stateless/exp \
    --max-duration 600 \
    --num-encoder-layers 12 \
    --rnn-hidden-size 1024 \
    --decoding-method $decoding_method \
    --use-averaged-model True \
    --beam 4 \
    --max-contexts 4 \
    --max-states 8 \
    --beam-size 4
done

The streaming decoding command using greedy search, fast beam search, and modified beam search is:

for decoding_method in greedy_search fast_beam_search modified_beam_search; do
  ./lstm_transducer_stateless/streaming_decode.py \
    --epoch 35 \
    --avg 15 \
    --exp-dir lstm_transducer_stateless/exp \
    --max-duration 600 \
    --num-encoder-layers 12 \
    --rnn-hidden-size 1024 \
    --decoding-method $decoding_method \
    --use-averaged-model True \
    --beam 4 \
    --max-contexts 4 \
    --max-states 8 \
    --beam-size 4
done

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/Zengwei/icefall-asr-librispeech-lstm-transducer-stateless-2022-08-18

LibriSpeech BPE training results (Pruned Stateless Conv-Emformer RNN-T 2)

conv_emformer_transducer_stateless2

It implements Emformer augmented with convolution module and simplified memory bank for streaming ASR. It is modified from torchaudio.

See https://github.com/k2-fsa/icefall/pull/440 for more details.

With lower latency setup, training on full librispeech

In this model, the lengths of chunk and right context are 32 frames (i.e., 0.32s) and 8 frames (i.e., 0.08s), respectively.

The WERs are:

	test-clean	test-other	comment	decoding mode
greedy search (max sym per frame 1)	3.5	9.09	--epoch 30 --avg 10	simulated streaming
greedy search (max sym per frame 1)	3.57	9.1	--epoch 30 --avg 10	streaming
fast beam search	3.5	8.91	--epoch 30 --avg 10	simulated streaming
fast beam search	3.54	8.91	--epoch 30 --avg 10	streaming
modified beam search	3.43	8.86	--epoch 30 --avg 10	simulated streaming
modified beam search	3.48	8.88	--epoch 30 --avg 10	streaming

The training command is:

./conv_emformer_transducer_stateless2/train.py \
  --world-size 6 \
  --num-epochs 30 \
  --start-epoch 1 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --full-libri 1 \
  --max-duration 280 \
  --master-port 12321 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32

The tensorboard log can be found at https://tensorboard.dev/experiment/W5MpxekiQLSPyM4fe5hbKg/

The simulated streaming decoding command using greedy search is:

./conv_emformer_transducer_stateless2/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method greedy_search \
  --use-averaged-model True

The simulated streaming decoding command using fast beam search is:

./conv_emformer_transducer_stateless2/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The simulated streaming decoding command using modified beam search is:

./conv_emformer_transducer_stateless2/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

The streaming decoding command using greedy search is:

./conv_emformer_transducer_stateless2/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method greedy_search \
  --use-averaged-model True

The streaming decoding command using fast beam search is:

./conv_emformer_transducer_stateless2/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The streaming decoding command using modified beam search is:

./conv_emformer_transducer_stateless2/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/Zengwei/icefall-asr-librispeech-conv-emformer-transducer-stateless2-2022-07-05

With higher latency setup, training on full librispeech

In this model, the lengths of chunk and right context are 64 frames (i.e., 0.64s) and 16 frames (i.e., 0.16s), respectively.

The WERs are:

	test-clean	test-other	comment	decoding mode
greedy search (max sym per frame 1)	3.3	8.71	--epoch 30 --avg 10	simulated streaming
greedy search (max sym per frame 1)	3.35	8.65	--epoch 30 --avg 10	streaming
fast beam search	3.27	8.58	--epoch 30 --avg 10	simulated streaming
fast beam search	3.31	8.48	--epoch 30 --avg 10	streaming
modified beam search	3.26	8.56	--epoch 30 --avg 10	simulated streaming
modified beam search	3.29	8.47	--epoch 30 --avg 10	streaming

The training command is:

./conv_emformer_transducer_stateless2/train.py \
  --world-size 4 \
  --num-epochs 30 \
  --start-epoch 1 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --full-libri 1 \
  --max-duration 280 \
  --master-port 12321 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32

The tensorboard log can be found at https://tensorboard.dev/experiment/eRx6XwbOQhGlywgD8lWBjw/

The simulated streaming decoding command using greedy search is:

./conv_emformer_transducer_stateless2/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32 \
  --decoding-method greedy_search \
  --use-averaged-model True

The simulated streaming decoding command using fast beam search is:

./conv_emformer_transducer_stateless2/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The simulated streaming decoding command using modified beam search is:

./conv_emformer_transducer_stateless2/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

The streaming decoding command using greedy search is:

./conv_emformer_transducer_stateless2/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32 \
  --decoding-method greedy_search \
  --use-averaged-model True

The streaming decoding command using fast beam search is:

./conv_emformer_transducer_stateless2/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The streaming decoding command using modified beam search is:

./conv_emformer_transducer_stateless2/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless2/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 64 \
  --cnn-module-kernel 31 \
  --left-context-length 64 \
  --right-context-length 16 \
  --memory-size 32 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/Zengwei/icefall-asr-librispeech-conv-emformer-transducer-stateless2-larger-latency-2022-07-06

LibriSpeech BPE training results (Pruned Stateless Streaming Conformer RNN-T)

pruned_transducer_stateless

See https://github.com/k2-fsa/icefall/pull/380 for more details.

Training on full librispeech

The WERs are (the number in the table formatted as test-clean & test-other):

We only trained 25 epochs for saving time, if you want to get better results you can train more epochs.

decoding method	left context	chunk size = 2	chunk size = 4	chunk size = 8	chunk size = 16
greedy search	32	4.74 & 11.38	4.57 & 10.86	4.18 & 10.37	3.87 & 9.85
greedy search	64	4.74 & 11.25	4.48 & 10.72	4.1 & 10.24	3.85 & 9.73
fast beam search	32	4.75 & 11.1	4.48 & 10.65	4.12 & 10.18	3.95 & 9.67
fast beam search	64	4.7 & 11	4.37 & 10.49	4.07 & 10.04	3.89 & 9.53
modified beam search	32	4.64 & 10.94	4.38 & 10.51	4.11 & 10.14	3.87 & 9.61
modified beam search	64	4.59 & 10.81	4.29 & 10.39	4.02 & 10.02	3.84 & 9.43

NOTE: The WERs in table above were decoded with simulate streaming method (i.e. using masking strategy), see commands below. We also have real streaming decoding script which should produce almost the same results. We tried adding right context in the real streaming decoding, but it seemed not to benefit the performance for all the models, the reasons might be the training and decoding mismatching.

The training command is:

./pruned_transducer_stateless/train.py \
  --exp-dir pruned_transducer_stateless/exp \
  --full-libri 1 \
  --dynamic-chunk-training 1 \
  --causal-convolution 1 \
  --short-chunk-size 20 \
  --num-left-chunks 4 \
  --max-duration 300 \
  --world-size 4 \
  --start-epoch 0 \
  --num-epochs 25

You can find the tensorboard log here https://tensorboard.dev/experiment/ofxRakE6R7WHB1AoB8Bweg/

The decoding command is:

decoding_method="greedy_search"  # "fast_beam_search", "modified_beam_search"

for chunk in 2 4 8 16; do
  for left in 32 64; do
    ./pruned_transducer_stateless/decode.py \
            --simulate-streaming 1 \
            --decode-chunk-size ${chunk} \
            --left-context ${left} \
            --causal-convolution 1 \
            --epoch 24 \
            --avg 10 \
            --exp-dir ./pruned_transducer_stateless/exp \
            --max-sym-per-frame 1 \
            --max-duration 1000 \
            --decoding-method ${decoding_method}
  done
done

Pre-trained models, training and decoding logs, and decoding results are available at https://huggingface.co/pkufool/icefall_librispeech_streaming_pruned_transducer_stateless_20220625

pruned_transducer_stateless2

See https://github.com/k2-fsa/icefall/pull/380 for more details.

Training on full librispeech

The WERs are (the number in the table formatted as test-clean & test-other):

We only trained 25 epochs for saving time, if you want to get better results you can train more epochs.

decoding method	left context	chunk size = 2	chunk size = 4	chunk size = 8	chunk size = 16
greedy search	32	4.2 & 10.64	3.97 & 10.03	3.83 & 9.58	3.7 & 9.11
greedy search	64	4.16 & 10.5	3.93 & 9.99	3.73 & 9.45	3.63 & 9.04
fast beam search	32	4.13 & 10.3	3.93 & 9.82	3.8 & 9.35	3.62 & 8.93
fast beam search	64	4.13 & 10.22	3.89 & 9.68	3.73 & 9.27	3.52 & 8.82
modified beam search	32	4.02 & 10.22	3.9 & 9.71	3.74 & 9.33	3.59 & 8.87
modified beam search	64	4.05 & 10.08	3.81 & 9.67	3.68 & 9.21	3.56 & 8.77

NOTE: The WERs in table above were decoded with simulate streaming method (i.e. using masking strategy), see commands below. We also have real streaming decoding script which should produce almost the same results. We tried adding right context in the real streaming decoding, but it seemed not to benefit the performance for all the models, the reasons might be the training and decoding mismatching.

The training command is:

./pruned_transducer_stateless2/train.py \
  --exp-dir pruned_transducer_stateless2/exp \
  --full-libri 1 \
  --dynamic-chunk-training 1 \
  --causal-convolution 1 \
  --short-chunk-size 20 \
  --num-left-chunks 4 \
  --max-duration 300 \
  --world-size 4 \
  --start-epoch 0 \
  --num-epochs 25

You can find the tensorboard log here https://tensorboard.dev/experiment/hbltNS5TQ1Kiw0D1vcoakw/

The decoding command is:

decoding_method="greedy_search"  # "fast_beam_search", "modified_beam_search"

for chunk in 2 4 8 16; do
  for left in 32 64; do
    ./pruned_transducer_stateless2/decode.py \
            --simulate-streaming 1 \
            --decode-chunk-size ${chunk} \
            --left-context ${left} \
            --causal-convolution 1 \
            --epoch 24 \
            --avg 10 \
            --exp-dir ./pruned_transducer_stateless2/exp \
            --max-sym-per-frame 1 \
            --max-duration 1000 \
            --decoding-method ${decoding_method}
  done
done

Pre-trained models, training and decoding logs, and decoding results are available at https://huggingface.co/pkufool/icefall_librispeech_streaming_pruned_transducer_stateless2_20220625

pruned_transducer_stateless3

See https://github.com/k2-fsa/icefall/pull/380 for more details.

Training on full librispeech (Use giga_prob = 0.5)

The WERs are (the number in the table formatted as test-clean & test-other):

decoding method	left context	chunk size = 2	chunk size = 4	chunk size = 8	chunk size = 16
greedy search	32	3.7 & 9.53	3.45 & 8.88	3.28 & 8.45	3.13 & 7.93
greedy search	64	3.69 & 9.36	3.39 & 8.68	3.28 & 8.19	3.08 & 7.83
fast beam search	32	3.71 & 9.18	3.36 & 8.65	3.23 & 8.23	3.17 & 7.78
fast beam search	64	3.61 & 9.03	3.46 & 8.43	3.2 & 8.0	3.11 & 7.63
modified beam search	32	3.56 & 9.08	3.34 & 8.58	3.21 & 8.14	3.06 & 7.73
modified beam search	64	3.55 & 8.86	3.29 & 8.34	3.16 & 8.01	3.05 & 7.57

NOTE: The WERs in table above were decoded with simulate streaming method (i.e. using masking strategy), see commands below. We also have real streaming decoding script which should produce almost the same results. We tried adding right context in the real streaming decoding, but it seemed not to benefit the performance for all the models, the reasons might be the training and decoding mismatching.

The training command is (Note: this model was trained with mix-precision training):

./pruned_transducer_stateless3/train.py \
  --exp-dir pruned_transducer_stateless3/exp \
  --full-libri 1 \
  --dynamic-chunk-training 1 \
  --causal-convolution 1 \
  --short-chunk-size 32 \
  --num-left-chunks 4 \
  --max-duration 300 \
  --world-size 4 \
  --use-fp16 1 \
  --start-epoch 0 \
  --num-epochs 37 \
  --num-workers 2 \
  --giga-prob 0.5

You can find the tensorboard log here https://tensorboard.dev/experiment/vL7dWVZqTYaSeoOED4rtow/

The decoding command is:

decoding_method="greedy_search"  # "fast_beam_search", "modified_beam_search"

for chunk in 2 4 8 16; do
  for left in 32 64; do
    ./pruned_transducer_stateless3/decode.py \
            --simulate-streaming 1 \
            --decode-chunk-size ${chunk} \
            --left-context ${left} \
            --causal-convolution 1 \
            --epoch 36 \
            --avg 8 \
            --exp-dir ./pruned_transducer_stateless3/exp \
            --max-sym-per-frame 1 \
            --max-duration 1000 \
            --decoding-method ${decoding_method}
  done
done

Pre-trained models, training and decoding logs, and decoding results are available at https://huggingface.co/pkufool/icefall_librispeech_streaming_pruned_transducer_stateless3_giga_0.5_20220625

Training on full librispeech (Use giga_prob = 0.9)

The WERs are (the number in the table formatted as test-clean & test-other):

decoding method	left context	chunk size = 2	chunk size = 4	chunk size = 8	chunk size = 16
greedy search	32	3.25 & 8.2	3.07 & 7.67	2.91 & 7.28	2.8 & 6.89
greedy search	64	3.22 & 8.12	3.05 & 7.59	2.91 & 7.07	2.78 & 6.81
fast beam search	32	3.26 & 8.2	3.06 & 7.56	2.98 & 7.08	2.77 & 6.75
fast beam search	64	3.24 & 8.09	3.06 & 7.43	2.88 & 7.03	2.73 & 6.68
modified beam search	32	3.13 & 7.91	2.99 & 7.45	2.83 & 6.98	2.68 & 6.75
modified beam search	64	3.08 & 7.8	2.97 & 7.37	2.81 & 6.82	2.66 & 6.67

NOTE: The WERs in table above were decoded with simulate streaming method (i.e. using masking strategy), see commands below. We also have real streaming decoding script which should produce almost the same results. We tried adding right context in the real streaming decoding, but it seemed not to benefit the performance for all the models, the reasons might be the training and decoding mismatching.

The training command is:

./pruned_transducer_stateless3/train.py \
  --exp-dir pruned_transducer_stateless3/exp \
  --full-libri 1 \
  --dynamic-chunk-training 1 \
  --causal-convolution 1 \
  --short-chunk-size 25 \
  --num-left-chunks 8 \
  --max-duration 300 \
  --world-size 8 \
  --start-epoch 0 \
  --num-epochs 26 \
  --num-workers 2 \
  --giga-prob 0.9

You can find the tensorboard log here https://tensorboard.dev/experiment/WBGBDzt7SByRnvCBEfQpGQ/

The decoding command is:

decoding_method="greedy_search"  # "fast_beam_search", "modified_beam_search"

for chunk in 2 4 8 16; do
  for left in 32 64; do
    ./pruned_transducer_stateless3/decode.py \
            --simulate-streaming 1 \
            --decode-chunk-size ${chunk} \
            --left-context ${left} \
            --causal-convolution 1 \
            --epoch 25 \
            --avg 12 \
            --exp-dir ./pruned_transducer_stateless3/exp \
            --max-sym-per-frame 1 \
            --max-duration 1000 \
            --decoding-method ${decoding_method}
  done
done

Pre-trained models, training and decoding logs, and decoding results are available at https://huggingface.co/pkufool/icefall_librispeech_streaming_pruned_transducer_stateless3_giga_0.9_20220625

pruned_transducer_stateless4

See https://github.com/k2-fsa/icefall/pull/380 for more details.

Training on full librispeech

The WERs are (the number in the table formatted as test-clean & test-other):

We only trained 25 epochs for saving time, if you want to get better results you can train more epochs.

decoding method	left context	chunk size = 2	chunk size = 4	chunk size = 8	chunk size = 16
greedy search	32	3.96 & 10.45	3.73 & 9.97	3.54 & 9.56	3.45 & 9.08
greedy search	64	3.9 & 10.34	3.7 & 9.9	3.53 & 9.41	3.39 & 9.03
fast beam search	32	3.9 & 10.09	3.69 & 9.65	3.58 & 9.28	3.46 & 8.91
fast beam search	64	3.82 & 10.03	3.67 & 9.56	3.51 & 9.18	3.43 & 8.78
modified beam search	32	3.78 & 10.0	3.63 & 9.54	3.43 & 9.29	3.39 & 8.84
modified beam search	64	3.76 & 9.95	3.54 & 9.48	3.4 & 9.13	3.33 & 8.74

NOTE: The WERs in table above were decoded with simulate streaming method (i.e. using masking strategy), see commands below. We also have real streaming decoding script which should produce almost the same results. We tried adding right context in the real streaming decoding, but it seemed not to benefit the performance for all the models, the reasons might be the training and decoding mismatching.

The training command is:

./pruned_transducer_stateless4/train.py \
  --exp-dir pruned_transducer_stateless4/exp \
  --full-libri 1 \
  --dynamic-chunk-training 1 \
  --causal-convolution 1 \
  --short-chunk-size 20 \
  --num-left-chunks 4 \
  --max-duration 300 \
  --world-size 4 \
  --start-epoch 1 \
  --num-epochs 25

You can find the tensorboard log here https://tensorboard.dev/experiment/97VKXf80Ru61CnP2ALWZZg/

The decoding command is:

decoding_method="greedy_search"  # "fast_beam_search", "modified_beam_search"

for chunk in 2 4 8 16; do
  for left in 32 64; do
    ./pruned_transducer_stateless4/decode.py \
            --simulate-streaming 1 \
            --decode-chunk-size ${chunk} \
            --left-context ${left} \
            --causal-convolution 1 \
            --epoch 25 \
            --avg 3 \
            --exp-dir ./pruned_transducer_stateless4/exp \
            --max-sym-per-frame 1 \
            --max-duration 1000 \
            --decoding-method ${decoding_method}
  done
done

Pre-trained models, training and decoding logs, and decoding results are available at https://huggingface.co/pkufool/icefall_librispeech_streaming_pruned_transducer_stateless4_20220625

pruned_transducer_stateless5

See https://github.com/k2-fsa/icefall/pull/454 for more details.

Training on full librispeech

The WERs are (the number in the table formatted as test-clean & test-other):

We only trained 25 epochs for saving time, if you want to get better results you can train more epochs.

decoding method	left context	chunk size = 2	chunk size = 4	chunk size = 8	chunk size = 16
greedy search	32	3.93 & 9.88	3.64 & 9.43	3.51 & 8.92	3.26 & 8.37
greedy search	64	4.84 & 9.81	3.59 & 9.27	3.44 & 8.83	3.23 & 8.33
fast beam search	32	3.86 & 9.77	3.67 & 9.3	3.5 & 8.83	3.27 & 8.33
fast beam search	64	3.79 & 9.68	3.57 & 9.21	3.41 & 8.72	3.25 & 8.27
modified beam search	32	3.84 & 9.71	3.66 & 9.38	3.47 & 8.86	3.26 & 8.42
modified beam search	64	3.81 & 9.59	3.58 & 9.2	3.44 & 8.74	3.23 & 8.35

NOTE: The WERs in table above were decoded with simulate streaming method (i.e. using masking strategy), see commands below. We also have real streaming decoding script which should produce almost the same results. We tried adding right context in the real streaming decoding, but it seemed not to benefit the performance for all the models, the reasons might be the training and decoding mismatching.

The training command is:

./pruned_transducer_stateless5/train.py \
  --exp-dir pruned_transducer_stateless5/exp \
  --num-encoder-layers 18 \
  --dim-feedforward 2048 \
  --nhead 8 \
  --encoder-dim 512 \
  --decoder-dim 512 \
  --joiner-dim 512 \
  --full-libri 1 \
  --dynamic-chunk-training 1 \
  --causal-convolution 1 \
  --short-chunk-size 20 \
  --num-left-chunks 4 \
  --max-duration 300 \
  --world-size 4 \
  --start-epoch 1 \
  --num-epochs 25

You can find the tensorboard log here https://tensorboard.dev/experiment/rO04h6vjTLyw0qSxjp4m4Q

The decoding command is:

decoding_method="greedy_search"  # "fast_beam_search", "modified_beam_search"

for chunk in 2 4 8 16; do
  for left in 32 64; do
    ./pruned_transducer_stateless5/decode.py \
            --num-encoder-layers 18 \
            --dim-feedforward 2048 \
            --nhead 8 \
            --encoder-dim 512 \
            --decoder-dim 512 \
            --joiner-dim 512 \
            --simulate-streaming 1 \
            --decode-chunk-size ${chunk} \
            --left-context ${left} \
            --causal-convolution 1 \
            --epoch 25 \
            --avg 3 \
            --exp-dir ./pruned_transducer_stateless5/exp \
            --max-sym-per-frame 1 \
            --max-duration 1000 \
            --decoding-method ${decoding_method}
  done
done

Pre-trained models, training and decoding logs, and decoding results are available at https://huggingface.co/pkufool/icefall_librispeech_streaming_pruned_transducer_stateless5_20220729

LibriSpeech BPE training results (Pruned Stateless Conv-Emformer RNN-T)

conv_emformer_transducer_stateless

It implements Emformer augmented with convolution module for streaming ASR. It is modified from torchaudio.

See https://github.com/k2-fsa/icefall/pull/389 for more details.

Training on full librispeech

In this model, the lengths of chunk and right context are 32 frames (i.e., 0.32s) and 8 frames (i.e., 0.08s), respectively.

The WERs are:

	test-clean	test-other	comment	decoding mode
greedy search (max sym per frame 1)	3.63	9.61	--epoch 30 --avg 10	simulated streaming
greedy search (max sym per frame 1)	3.64	9.65	--epoch 30 --avg 10	streaming
fast beam search	3.61	9.4	--epoch 30 --avg 10	simulated streaming
fast beam search	3.58	9.5	--epoch 30 --avg 10	streaming
modified beam search	3.56	9.41	--epoch 30 --avg 10	simulated streaming
modified beam search	3.54	9.46	--epoch 30 --avg 10	streaming

The training command is:

./conv_emformer_transducer_stateless/train.py \
  --world-size 6 \
  --num-epochs 30 \
  --start-epoch 1 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --full-libri 1 \
  --max-duration 300 \
  --master-port 12321 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32

The tensorboard log can be found at https://tensorboard.dev/experiment/4em2FLsxRwGhmoCRQUEoDw/

The simulated streaming decoding command using greedy search is:

./conv_emformer_transducer_stateless/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method greedy_search \
  --use-averaged-model True

The simulated streaming decoding command using fast beam search is:

./conv_emformer_transducer_stateless/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The simulated streaming decoding command using modified beam search is:

./conv_emformer_transducer_stateless/decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --max-duration 300 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

The streaming decoding command using greedy search is:

./conv_emformer_transducer_stateless/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method greedy_search \
  --use-averaged-model True

The streaming decoding command using fast beam search is:

./conv_emformer_transducer_stateless/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The streaming decoding command using modified beam search is:

./conv_emformer_transducer_stateless/streaming_decode.py \
  --epoch 30 \
  --avg 10 \
  --exp-dir conv_emformer_transducer_stateless/exp \
  --num-decode-streams 2000 \
  --num-encoder-layers 12 \
  --chunk-length 32 \
  --cnn-module-kernel 31 \
  --left-context-length 32 \
  --right-context-length 8 \
  --memory-size 32 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/Zengwei/icefall-asr-librispeech-conv-emformer-transducer-stateless-2022-06-11

LibriSpeech BPE training results (Pruned Stateless Emformer RNN-T)

pruned_stateless_emformer_rnnt2

Use https://github.com/k2-fsa/icefall/pull/390.

Use Emformer from torchaudio for streaming ASR. The Emformer model is imported from torchaudio without modifications.

You can use https://github.com/k2-fsa/sherpa to deploy it.

	test-clean	test-other	comment
greedy search (max sym per frame 1)	4.28	11.42	--epoch 39 --avg 6 --max-duration 600
modified beam search	4.22	11.16	--epoch 39 --avg 6 --max-duration 600
fast beam search	4.29	11.26	--epoch 39 --avg 6 --max-duration 600

The training commands are:

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./pruned_stateless_emformer_rnnt2/train.py \
  --world-size 8 \
  --num-epochs 40 \
  --start-epoch 1 \
  --exp-dir pruned_stateless_emformer_rnnt2/exp-full \
  --full-libri 1 \
  --use-fp16 0 \
  --max-duration 200 \
  --prune-range 5 \
  --lm-scale 0.25 \
  --master-port 12358 \
  --num-encoder-layers 18 \
  --left-context-length 128 \
  --segment-length 8 \
  --right-context-length 4

The tensorboard log can be found at https://tensorboard.dev/experiment/ZyiqhAhmRjmr49xml4ofLw/

The decoding commands are:

for m in greedy_search fast_beam_search modified_beam_search; do
  for epoch in 39; do
    for avg in 6; do
      ./pruned_stateless_emformer_rnnt2/decode.py \
        --epoch $epoch \
        --avg $avg \
        --use-averaged-model 1 \
        --exp-dir pruned_stateless_emformer_rnnt2/exp-full \
        --max-duration 50 \
        --decoding-method $m \
        --num-encoder-layers 18 \
        --left-context-length 128 \
        --segment-length 8 \
        --right-context-length 4
    done
  done
done

You can find a pretrained model, training logs, decoding logs, and decoding results at: https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-stateless-emformer-rnnt2-2022-06-01

LibriSpeech BPE training results (Pruned Stateless Transducer 5)

pruned_transducer_stateless5

Same as Pruned Stateless Transducer 2 but with more layers.

See https://github.com/k2-fsa/icefall/pull/330

Note that models in pruned_transducer_stateless and pruned_transducer_stateless2 have about 80 M parameters.

The notations large and medium below are from the Conformer paper, where the large model has about 118 M parameters and the medium model has 30.8 M parameters.

Large

Number of model parameters 118129516 (i.e, 118.13 M).

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.43	5.72	--epoch 30 --avg 10 --max-duration 600
modified beam search	2.43	5.69	--epoch 30 --avg 10 --max-duration 600
fast beam search	2.43	5.67	--epoch 30 --avg 10 --max-duration 600

The training commands are:

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./pruned_transducer_stateless5/train.py \
  --world-size 8 \
  --num-epochs 30 \
  --start-epoch 1 \
  --full-libri 1 \
  --exp-dir pruned_transducer_stateless5/exp-L \
  --max-duration 300 \
  --use-fp16 0 \
  --num-encoder-layers 18 \
  --dim-feedforward 2048 \
  --nhead 8 \
  --encoder-dim 512 \
  --decoder-dim 512 \
  --joiner-dim 512

The tensorboard log can be found at https://tensorboard.dev/experiment/aWzDj5swSE2VmcOYgoe3vQ

The decoding commands are:

for method in greedy_search modified_beam_search fast_beam_search; do
  ./pruned_transducer_stateless5/decode.py \
    --epoch 30 \
    --avg 10 \
    --exp-dir ./pruned_transducer_stateless5/exp-L \
    --max-duration 600 \
    --decoding-method $method \
    --max-sym-per-frame 1 \
    --num-encoder-layers 18 \
    --dim-feedforward 2048 \
    --nhead 8 \
    --encoder-dim 512 \
    --decoder-dim 512 \
    --joiner-dim 512 \
    --use-averaged-model True
done

You can find a pretrained model, training logs, decoding logs, and decoding results at: https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless5-2022-07-07

Medium

Number of model parameters 30896748 (i.e, 30.9 M).

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.87	6.92	--epoch 30 --avg 10 --max-duration 600
modified beam search	2.83	6.75	--epoch 30 --avg 10 --max-duration 600
fast beam search	2.81	6.76	--epoch 30 --avg 10 --max-duration 600

The training commands are:

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./pruned_transducer_stateless5/train.py \
  --world-size 8 \
  --num-epochs 30 \
  --start-epoch 1 \
  --full-libri 1 \
  --exp-dir pruned_transducer_stateless5/exp-M \
  --max-duration 300 \
  --use-fp16 0 \
  --num-encoder-layers 18 \
  --dim-feedforward 1024 \
  --nhead 4 \
  --encoder-dim 256 \
  --decoder-dim 512 \
  --joiner-dim 512

The tensorboard log can be found at https://tensorboard.dev/experiment/04xtWUKPRmebSnpzN1GMHQ

The decoding commands are:

for method in greedy_search modified_beam_search fast_beam_search; do
  ./pruned_transducer_stateless5/decode.py \
    --epoch 30 \
    --avg 10 \
    --exp-dir ./pruned_transducer_stateless5/exp-M \
    --max-duration 600 \
    --decoding-method $method \
    --max-sym-per-frame 1 \
    --num-encoder-layers 18 \
    --dim-feedforward 1024 \
    --nhead 4 \
    --encoder-dim 256 \
    --decoder-dim 512 \
    --joiner-dim 512 \
    --use-averaged-model True
done

You can find a pretrained model, training logs, decoding logs, and decoding results at: https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless5-M-2022-07-07

Baseline-2

It has 87.8 M parameters. Compared to the model in pruned_transducer_stateless2, its has more layers (24 v.s 12) but a narrower model (1536 feedforward dim and 384 encoder dim vs 2048 feed forward dim and 512 encoder dim).

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.54	5.72	--epoch 30 --avg 10 --max-duration 600
modified beam search	2.47	5.71	--epoch 30 --avg 10 --max-duration 600
modified beam search + RNNLM shallow fusion	2.27	5.24	--epoch 30 --avg 10 --max-duration 600
fast beam search	2.5	5.72	--epoch 30 --avg 10 --max-duration 600

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./pruned_transducer_stateless5/train.py \
  --world-size 8 \
  --num-epochs 30 \
  --start-epoch 1 \
  --full-libri 1 \
  --exp-dir pruned_transducer_stateless5/exp-B \
  --max-duration 300 \
  --use-fp16 0 \
  --num-encoder-layers 24 \
  --dim-feedforward 1536 \
  --nhead 8 \
  --encoder-dim 384 \
  --decoder-dim 512 \
  --joiner-dim 512

The tensorboard log can be found at https://tensorboard.dev/experiment/foVHNyqiRi2LhybmRUOAyg

The decoding commands are:

for method in greedy_search modified_beam_search fast_beam_search; do
  ./pruned_transducer_stateless5/decode.py \
    --epoch 30 \
    --avg 10 \
    --exp-dir ./pruned_transducer_stateless5/exp-B \
    --max-duration 600 \
    --decoding-method $method \
    --max-sym-per-frame 1 \
    --num-encoder-layers 24 \
    --dim-feedforward 1536 \
    --nhead 8 \
    --encoder-dim 384 \
    --decoder-dim 512 \
    --joiner-dim 512 \
    --use-averaged-model True
done

To decode with RNNLM shallow fusion, use the following decoding command. A well-trained RNNLM can be found here: https://huggingface.co/ezerhouni/icefall-librispeech-rnn-lm/tree/main

for method in greedy_search modified_beam_search fast_beam_search; do
  ./pruned_transducer_stateless5/decode.py \
    --epoch 30 \
    --avg 10 \
    --exp-dir ./pruned_transducer_stateless5/exp-B \
    --max-duration 600 \
    --decoding-method modified_beam_search_rnnlm_shallow_fusion \
    --max-sym-per-frame 1 \
    --num-encoder-layers 24 \
    --dim-feedforward 1536 \
    --nhead 8 \
    --encoder-dim 384 \
    --decoder-dim 512 \
    --joiner-dim 512 \
    --use-averaged-model True
    --beam 4 \
    --max-contexts 4 \
    --rnn-lm-scale 0.4 \
    --rnn-lm-exp-dir /path/to/RNNLM/exp \
    --rnn-lm-epoch 99 \
    --rnn-lm-avg 1 \
    --rnn-lm-num-layers 3 \
    --rnn-lm-tie-weights 1
done

You can find a pretrained model, training logs, decoding logs, and decoding results at: https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless5-B-2022-07-07

LibriSpeech BPE training results (Pruned Stateless Transducer 4)

pruned_transducer_stateless4

This version saves averaged model during training, and decodes with averaged model.

See https://github.com/k2-fsa/icefall/issues/337 for details about the idea of model averaging.

Training on full librispeech

See https://github.com/k2-fsa/icefall/pull/344

Using commit ec0b0e92297cc03fdb09f48cd235e84d2c04156b.

The WERs are:

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.75	6.74	--epoch 30 --avg 6 --use-averaged-model False
greedy search (max sym per frame 1)	2.69	6.64	--epoch 30 --avg 6 --use-averaged-model True
fast beam search	2.72	6.67	--epoch 30 --avg 6 --use-averaged-model False
fast beam search	2.66	6.6	--epoch 30 --avg 6 --use-averaged-model True
modified beam search	2.67	6.68	--epoch 30 --avg 6 --use-averaged-model False
modified beam search	2.62	6.57	--epoch 30 --avg 6 --use-averaged-model True

The training command is:

./pruned_transducer_stateless4/train.py \
  --world-size 6 \
  --num-epochs 30 \
  --start-epoch 1 \
  --exp-dir pruned_transducer_stateless4/exp \
  --full-libri 1 \
  --max-duration 300 \
  --save-every-n 8000 \
  --keep-last-k 20 \
  --average-period 100

The tensorboard log can be found at https://tensorboard.dev/experiment/QOGSPBgsR8KzcRMmie9JGw/

The decoding command using greedy search is:

./pruned_transducer_stateless4/decode.py \
  --epoch 30 \
  --avg 6 \
  --exp-dir pruned_transducer_stateless4/exp \
  --max-duration 300 \
  --decoding-method greedy_search \
  --use-averaged-model True

The decoding command using fast beam search is:

./pruned_transducer_stateless4/decode.py \
  --epoch 30 \
  --avg 6 \
  --exp-dir pruned_transducer_stateless4/exp \
  --max-duration 300 \
  --decoding-method fast_beam_search \
  --use-averaged-model True \
  --beam 4 \
  --max-contexts 4 \
  --max-states 8

The decoding command using modified beam search is:

./pruned_transducer_stateless4/decode.py \
  --epoch 30 \
  --avg 6 \
  --exp-dir pruned_transducer_stateless4/exp \
  --max-duration 300 \
  --decoding-method modified_beam_search \
  --use-averaged-model True \
  --beam-size 4

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/Zengwei/icefall-asr-librispeech-pruned-transducer-stateless4-2022-06-03

Training on train-clean-100

See https://github.com/k2-fsa/icefall/pull/344

Using commit ec0b0e92297cc03fdb09f48cd235e84d2c04156b.

The WERs are:

	test-clean	test-other	comment
greedy search (max sym per frame 1)	7.0	18.95	--epoch 30 --avg 10 --use_averaged_model False
greedy search (max sym per frame 1)	6.92	18.65	--epoch 30 --avg 10 --use_averaged_model True
fast beam search	6.82	18.47	--epoch 30 --avg 10 --use_averaged_model False
fast beam search	6.74	18.2	--epoch 30 --avg 10 --use_averaged_model True
modified beam search	6.74	18.39	--epoch 30 --avg 10 --use_averaged_model False
modified beam search	6.74	18.12	--epoch 30 --avg 10 --use_averaged_model True

The training command is:

./pruned_transducer_stateless4/train.py \
  --world-size 3 \
  --num-epochs 30 \
  --start-epoch 1 \
  --exp-dir pruned_transducer_stateless4/exp \
  --full-libri 0 \
  --max-duration 300 \
  --save-every-n 8000 \
  --keep-last-k 20 \
  --average-period 100

The tensorboard log can be found at https://tensorboard.dev/experiment/YVYHq1irQS69s9bW1vQ06Q/

LibriSpeech BPE training results (Pruned Stateless Transducer 3, 2022-04-29)

pruned_transducer_stateless3

Same as Pruned Stateless Transducer 2 but using the XL subset from GigaSpeech as extra training data.

During training, it selects either a batch from GigaSpeech with prob giga_prob or a batch from LibriSpeech with prob 1 - giga_prob. All utterances within a batch come from the same dataset.

Using commit ac84220de91dee10c00e8f4223287f937b1930b6.

See https://github.com/k2-fsa/icefall/pull/312.

The WERs are:

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.21	5.09	--epoch 27 --avg 2 --max-duration 600
greedy search (max sym per frame 1)	2.25	5.02	--epoch 27 --avg 12 --max-duration 600
modified beam search	2.19	5.03	--epoch 25 --avg 6 --max-duration 600
modified beam search	2.23	4.94	--epoch 27 --avg 10 --max-duration 600
beam search	2.16	4.95	--epoch 25 --avg 7 --max-duration 600
fast beam search	2.21	4.96	--epoch 27 --avg 10 --max-duration 600
fast beam search	2.19	4.97	--epoch 27 --avg 12 --max-duration 600

The training commands are:

./prepare.sh
./prepare_giga_speech.sh

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./pruned_transducer_stateless3/train.py \
  --world-size 8 \
  --num-epochs 30 \
  --start-epoch 0 \
  --full-libri 1 \
  --exp-dir pruned_transducer_stateless3/exp \
  --max-duration 300 \
  --use-fp16 1 \
  --lr-epochs 4 \
  --num-workers 2 \
  --giga-prob 0.8

The tensorboard log can be found at https://tensorboard.dev/experiment/gaD34WeYSMCOkzoo3dZXGg/ (Note: The training process is killed manually after saving epoch-28.pt.)

Pretrained models, training logs, decoding logs, and decoding results are available at https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-04-29

The decoding commands are:

# greedy search
./pruned_transducer_stateless3/decode.py \
    --epoch 27 \
    --avg 2 \
    --exp-dir ./pruned_transducer_stateless3/exp \
    --max-duration 600 \
    --decoding-method greedy_search \
    --max-sym-per-frame 1

# modified beam search
./pruned_transducer_stateless3/decode.py \
    --epoch 25 \
    --avg 6 \
    --exp-dir ./pruned_transducer_stateless3/exp \
    --max-duration 600 \
    --decoding-method modified_beam_search \
    --max-sym-per-frame 1

# beam search
./pruned_transducer_stateless3/decode.py \
    --epoch 25 \
    --avg 7 \
    --exp-dir ./pruned_transducer_stateless3/exp \
    --max-duration 600 \
    --decoding-method beam_search \
    --max-sym-per-frame 1

# fast beam search
for epoch in 27; do
  for avg in 10 12; do
    ./pruned_transducer_stateless3/decode.py \
        --epoch $epoch \
        --avg $avg \
        --exp-dir ./pruned_transducer_stateless3/exp \
        --max-duration 600 \
        --decoding-method fast_beam_search \
        --max-states 32 \
        --beam 8
  done
done

The following table shows the Nbest oracle WER for fast beam search.

epoch	avg	num_paths	nbest_scale	test-clean	test-other
27	10	50	0.5	0.91	2.74
27	10	50	0.8	0.94	2.82
27	10	50	1.0	1.06	2.88
27	10	100	0.5	0.82	2.58
27	10	100	0.8	0.92	2.65
27	10	100	1.0	0.95	2.77
27	10	200	0.5	0.81	2.50
27	10	200	0.8	0.85	2.56
27	10	200	1.0	0.91	2.64
27	10	400	0.5	N/A	N/A
27	10	400	0.8	0.81	2.49
27	10	400	1.0	0.85	2.54

The Nbest oracle WER is computed using the following steps:

• 1. Use fast_beam_search to produce a lattice.
• 2. Extract N paths from the lattice using k2.random_path
• 3. Unique paths so that each path has a distinct sequence of tokens
• 4. Compute the edit distance of each path with the ground truth
• 5. The path with the lowest edit distance is the final output and is used to compute the WER

The command to compute the Nbest oracle WER is:

for epoch in 27; do
  for avg in 10 ; do
    for num_paths in 50 100 200 400; do
      for nbest_scale in 0.5 0.8 1.0; do
        ./pruned_transducer_stateless3/decode.py \
            --epoch $epoch \
            --avg $avg \
            --exp-dir ./pruned_transducer_stateless3/exp \
            --max-duration 600 \
            --decoding-method fast_beam_search_nbest_oracle \
            --num-paths $num_paths \
            --max-states 32 \
            --beam 8 \
            --nbest-scale $nbest_scale
      done
    done
  done
done

LibriSpeech BPE training results (Pruned Transducer 3, 2022-05-13)

Same setup as pruned_transducer_stateless3 (2022-04-29) but change --giga-prob from 0.8 to 0.9. Also use repeat on gigaspeech XL subset so that the gigaspeech dataloader never exhausts.

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.03	4.70	--iter 1224000 --avg 14 --max-duration 600
modified beam search	2.00	4.63	--iter 1224000 --avg 14 --max-duration 600
fast beam search	2.10	4.68	--iter 1224000 --avg 14 --max-duration 600

The training commands are:

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./prepare.sh
./prepare_giga_speech.sh

./pruned_transducer_stateless3/train.py \
  --world-size 8 \
  --num-epochs 30 \
  --start-epoch 0 \
  --full-libri 1 \
  --exp-dir pruned_transducer_stateless3/exp-0.9 \
  --max-duration 300 \
  --use-fp16 1 \
  --lr-epochs 4 \
  --num-workers 2 \
  --giga-prob 0.9

The tensorboard log is available at https://tensorboard.dev/experiment/HpocR7dKS9KCQkJeYxfXug/

Decoding commands:

for iter in 1224000; do
  for avg in 14; do
    for method in greedy_search modified_beam_search fast_beam_search ; do
      ./pruned_transducer_stateless3/decode.py \
        --iter $iter \
        --avg $avg \
        --exp-dir ./pruned_transducer_stateless3/exp-0.9/ \
        --max-duration 600 \
        --decoding-method $method \
        --max-sym-per-frame 1 \
        --beam 4 \
        --max-contexts 32
    done
  done
done

The pretrained models, training logs, decoding logs, and decoding results can be found at https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless3-2022-05-13

LibriSpeech BPE training results (Pruned Transducer 2)

pruned_transducer_stateless2

This is with a reworked version of the conformer encoder, with many changes.

Training on full librispeech

Using commit 34aad74a2c849542dd5f6359c9e6b527e8782fd6. See https://github.com/k2-fsa/icefall/pull/288

The WERs are:

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.62	6.37	--epoch 25 --avg 8 --max-duration 600
fast beam search	2.61	6.17	--epoch 25 --avg 8 --max-duration 600 --decoding-method fast_beam_search
modified beam search	2.59	6.19	--epoch 25 --avg 8 --max-duration 600 --decoding-method modified_beam_search
greedy search (max sym per frame 1)	2.70	6.04	--epoch 34 --avg 10 --max-duration 600
fast beam search	2.66	6.00	--epoch 34 --avg 10 --max-duration 600 --decoding-method fast_beam_search
greedy search (max sym per frame 1)	2.62	6.03	--epoch 38 --avg 10 --max-duration 600
fast beam search	2.57	5.95	--epoch 38 --avg 10 --max-duration 600 --decoding-method fast_beam_search

The train and decode commands are:

python3 ./pruned_transducer_stateless2/train.py \
  --exp-dir=pruned_transducer_stateless2/exp \
  --world-size 8 \
  --num-epochs 26 \
  --full-libri 1 \
  --max-duration 300

and:

python3 ./pruned_transducer_stateless2/decode.py \
  --exp-dir pruned_transducer_stateless2/exp \
  --epoch 25 \
  --avg 8 \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 600

The Tensorboard log is at https://tensorboard.dev/experiment/Xoz0oABMTWewo1slNFXkyA (apologies, log starts only from epoch 3).

The pretrained models, training logs, decoding logs, and decoding results can be found at https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless2-2022-04-29

Training on train-clean-100:

Trained with 1 job:

python3 ./pruned_transducer_stateless2/train.py \
  --exp-dir=pruned_transducer_stateless2/exp_100h_ws1 \
  --world-size 1 \
  --num-epochs 40  \
  --full-libri 0 \
  --max-duration 300

and decoded with:

python3 ./pruned_transducer_stateless2/decode.py \
  --exp-dir pruned_transducer_stateless2/exp_100h_ws1 \
  --epoch 19 \
  --avg 8 \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 600

The Tensorboard log is at https://tensorboard.dev/experiment/AhnhooUBRPqTnaggoqo7lg (learning rate schedule is not visible due to a since-fixed bug).

	test-clean	test-other	comment
greedy search (max sym per frame 1)	7.12	18.42	--epoch 19 --avg 8
greedy search (max sym per frame 1)	6.71	17.77	--epoch 29 --avg 8
greedy search (max sym per frame 1)	6.64	17.19	--epoch 39 --avg 10
fast beam search	6.58	17.27	--epoch 29 --avg 8 --decoding-method fast_beam_search
fast beam search	6.53	16.82	--epoch 39 --avg 10 --decoding-method fast_beam_search

Trained with 2 jobs:

python3 ./pruned_transducer_stateless2/train.py \
  --exp-dir=pruned_transducer_stateless2/exp_100h_ws2 \
  --world-size 2 \
  --num-epochs 40  \
  --full-libri 0 \
  --max-duration 300

and decoded with:

python3 ./pruned_transducer_stateless2/decode.py \
  --exp-dir pruned_transducer_stateless2/exp_100h_ws2 \
  --epoch 19 \
  --avg 8 \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 600

The Tensorboard log is at https://tensorboard.dev/experiment/dvOC9wsrSdWrAIdsebJILg/ (learning rate schedule is not visible due to a since-fixed bug).

	test-clean	test-other	comment
greedy search (max sym per frame 1)	7.05	18.77	--epoch 19 --avg 8
greedy search (max sym per frame 1)	6.82	18.14	--epoch 29 --avg 8
greedy search (max sym per frame 1)	6.81	17.66	--epoch 30 --avg 10

Trained with 4 jobs:

python3 ./pruned_transducer_stateless2/train.py \
  --exp-dir=pruned_transducer_stateless2/exp_100h_ws4 \
  --world-size 4 \
  --num-epochs 40  \
  --full-libri 0 \
  --max-duration 300

and decoded with:

python3 ./pruned_transducer_stateless2/decode.py \
  --exp-dir pruned_transducer_stateless2/exp_100h_ws4 \
  --epoch 19 \
  --avg 8 \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 600

The Tensorboard log is at https://tensorboard.dev/experiment/a3T0TyC0R5aLj5bmFbRErA/ (learning rate schedule is not visible due to a since-fixed bug).

	test-clean	test-other	comment
greedy search (max sym per frame 1)	7.31	19.55	--epoch 19 --avg 8
greedy search (max sym per frame 1)	7.08	18.59	--epoch 29 --avg 8
greedy search (max sym per frame 1)	6.86	18.29	--epoch 30 --avg 10

Trained with 1 job, with --use-fp16=True --max-duration=300 i.e. with half-precision floats (but without increasing max-duration), after merging https://github.com/k2-fsa/icefall/pull/305. Train command was

python3 ./pruned_transducer_stateless2/train.py \
  --exp-dir=pruned_transducer_stateless2/exp_100h_fp16 \
  --world-size 1 \
  --num-epochs 40  \
  --full-libri 0 \
  --max-duration 300 \
  --use-fp16 True

The Tensorboard log is at https://tensorboard.dev/experiment/DAtGG9lpQJCROUDwPNxwpA

	test-clean	test-other	comment
greedy search (max sym per frame 1)	7.10	18.57	--epoch 19 --avg 8
greedy search (max sym per frame 1)	6.81	17.84	--epoch 29 --avg 8
greedy search (max sym per frame 1)	6.63	17.39	--epoch 30 --avg 10

Trained with 1 job, with --use-fp16=True --max-duration=500, i.e. with half-precision floats and max-duration increased from 300 to 500, after merging https://github.com/k2-fsa/icefall/pull/305. Train command was

python3 ./pruned_transducer_stateless2/train.py \
  --exp-dir=pruned_transducer_stateless2/exp_100h_fp16 \
  --world-size 1 \
  --num-epochs 40  \
  --full-libri 0 \
  --max-duration 500 \
  --use-fp16 True

The Tensorboard log is at https://tensorboard.dev/experiment/Km7QBHYnSLWs4qQnAJWsaA

	test-clean	test-other	comment
greedy search (max sym per frame 1)	7.10	18.79	--epoch 19 --avg 8
greedy search (max sym per frame 1)	6.92	18.16	--epoch 29 --avg 8
greedy search (max sym per frame 1)	6.89	17.75	--epoch 30 --avg 10

LibriSpeech BPE training results (Pruned Transducer)

Conformer encoder + non-current decoder. The decoder contains only an embedding layer, a Conv1d (with kernel size 2) and a linear layer (to transform tensor dim).

2022-03-12

pruned_transducer_stateless

Using commit 1603744469d167d848e074f2ea98c587153205fa. See https://github.com/k2-fsa/icefall/pull/248

The WERs are:

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.62	6.37	--epoch 42 --avg 11 --max-duration 100
greedy search (max sym per frame 2)	2.62	6.37	--epoch 42 --avg 11 --max-duration 100
greedy search (max sym per frame 3)	2.62	6.37	--epoch 42 --avg 11 --max-duration 100
modified beam search (beam size 4)	2.56	6.27	--epoch 42 --avg 11 --max-duration 100
beam search (beam size 4)	2.57	6.27	--epoch 42 --avg 11 --max-duration 100

The decoding time for test-clean and test-other is given below: (A V100 GPU with 32 GB RAM is used for decoding. Note: Not all GPU RAM is used during decoding.)

decoding method	test-clean (seconds)	test-other (seconds)
greedy search (--max-sym-per-frame=1)	160	159
greedy search (--max-sym-per-frame=2)	184	177
greedy search (--max-sym-per-frame=3)	210	213
modified beam search (--beam-size 4)	273	269
beam search (--beam-size 4)	2741	2221

We recommend you to use modified_beam_search.

Training command:

cd egs/librispeech/ASR/
./prepare.sh

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

. path.sh

./pruned_transducer_stateless/train.py \
  --world-size 8 \
  --num-epochs 60 \
  --start-epoch 0 \
  --exp-dir pruned_transducer_stateless/exp \
  --full-libri 1 \
  --max-duration 300 \
  --prune-range 5 \
  --lr-factor 5 \
  --lm-scale 0.25

The tensorboard training log can be found at https://tensorboard.dev/experiment/WKRFY5fYSzaVBHahenpNlA/

The command for decoding is:

epoch=42
avg=11
sym=1

# greedy search

./pruned_transducer_stateless/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./pruned_transducer_stateless/exp \
  --max-duration 100 \
  --decoding-method greedy_search \
  --beam-size 4 \
  --max-sym-per-frame $sym

# modified beam search
./pruned_transducer_stateless/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./pruned_transducer_stateless/exp \
  --max-duration 100 \
  --decoding-method modified_beam_search \
  --beam-size 4

# beam search
# (not recommended)
./pruned_transducer_stateless/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./pruned_transducer_stateless/exp \
  --max-duration 100 \
  --decoding-method beam_search \
  --beam-size 4

You can find a pre-trained model, decoding logs, and decoding results at https://huggingface.co/csukuangfj/icefall-asr-librispeech-pruned-transducer-stateless-2022-03-12

2022-02-18

pruned_transducer_stateless

The WERs are

	test-clean	test-other	comment
greedy search	2.85	6.98	--epoch 28 --avg 15 --max-duration 100

The training command for reproducing is given below:

export CUDA_VISIBLE_DEVICES="0,1,2,3"

./pruned_transducer_stateless/train.py \
  --world-size 4 \
  --num-epochs 30 \
  --start-epoch 0 \
  --exp-dir pruned_transducer_stateless/exp \
  --full-libri 1 \
  --max-duration 300 \
  --prune-range 5 \
  --lr-factor 5 \
  --lm-scale 0.25 \

The tensorboard training log can be found at https://tensorboard.dev/experiment/ejG7VpakRYePNNj6AbDEUw/#scalars

The decoding command is:

epoch=28
avg=15

## greedy search
./pruned_transducer_stateless/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir pruned_transducer_stateless/exp \
  --max-duration 100

LibriSpeech BPE training results (Transducer)

Conformer encoder + embedding decoder

Conformer encoder + non-recurrent decoder. The decoder contains only an embedding layer and a Conv1d (with kernel size 2).

See

• ./transducer_stateless
• ./transducer_stateless_multi_datasets

2022-03-01

Using commit 2332ba312d7ce72f08c7bac1e3312f7e3dd722dc.

It uses GigaSpeech as extra training data. 20% of the time it selects a batch from L subset of GigaSpeech and 80% of the time it selects a batch from LibriSpeech.

The WERs are

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.64	6.55	--epoch 39 --avg 15 --max-duration 100
modified beam search (beam size 4)	2.61	6.46	--epoch 39 --avg 15 --max-duration 100

The training command for reproducing is given below:

cd egs/librispeech/ASR/
./prepare.sh
./prepare_giga_speech.sh

export CUDA_VISIBLE_DEVICES="0,1,2,3"

./transducer_stateless_multi_datasets/train.py \
  --world-size 4 \
  --num-epochs 40 \
  --start-epoch 0 \
  --exp-dir transducer_stateless_multi_datasets/exp-full-2 \
  --full-libri 1 \
  --max-duration 300 \
  --lr-factor 5 \
  --bpe-model data/lang_bpe_500/bpe.model \
  --modified-transducer-prob 0.25 \
  --giga-prob 0.2

The tensorboard training log can be found at https://tensorboard.dev/experiment/xmo5oCgrRVelH9dCeOkYBg/

The decoding command is:

epoch=39
avg=15
sym=1

# greedy search
./transducer_stateless_multi_datasets/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir transducer_stateless_multi_datasets/exp-full-2 \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 100 \
  --context-size 2 \
  --max-sym-per-frame $sym

# modified beam search
./transducer_stateless_multi_datasets/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir transducer_stateless_multi_datasets/exp-full-2 \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 100 \
  --context-size 2 \
  --decoding-method modified_beam_search \
  --beam-size 4

You can find a pretrained model by visiting https://huggingface.co/csukuangfj/icefall-asr-librispeech-transducer-stateless-multi-datasets-bpe-500-2022-03-01

2022-04-19

transducer_stateless2

This version uses torchaudio's RNN-T loss.

Using commit fce7f3cd9a486405ee008bcbe4999264f27774a3. See https://github.com/k2-fsa/icefall/pull/316

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.65	6.30	--epoch 59 --avg 10 --max-duration 600
greedy search (max sym per frame 2)	2.62	6.23	--epoch 59 --avg 10 --max-duration 100
greedy search (max sym per frame 3)	2.62	6.23	--epoch 59 --avg 10 --max-duration 100
modified beam search	2.63	6.15	--epoch 59 --avg 10 --max-duration 100 --decoding-method modified_beam_search
beam search	2.59	6.15	--epoch 59 --avg 10 --max-duration 100 --decoding-method beam_search

Note: This model is trained with standard RNN-T loss. Neither modified transducer nor pruned RNN-T is used. You can see that there is a performance degradation in WER when we limit the max symbol per frame to 1.

The number of active paths in modified_beam_search and beam_search is 4.

The training and decoding commands are:

export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"

./transducer_stateless2/train.py \
  --world-size 8 \
  --num-epochs 60 \
  --start-epoch 0 \
  --exp-dir transducer_stateless2/exp-2 \
  --full-libri 1 \
  --max-duration 300 \
  --lr-factor 5

epoch=59
avg=10
# greedy search
./transducer_stateless2/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./transducer_stateless2/exp-2 \
  --max-duration 600 \
  --decoding-method greedy_search \
  --max-sym-per-frame 1

# modified beam search
./transducer_stateless2/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./transducer_stateless2/exp-2 \
  --max-duration 100 \
  --decoding-method modified_beam_search \

# beam search
./transducer_stateless2/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir ./transducer_stateless2/exp-2 \
  --max-duration 100 \
  --decoding-method beam_search \

The tensorboard log is at https://tensorboard.dev/experiment/oAlle3dxQD2EY8ePwjIGuw/.

You can find a pre-trained model, decoding logs, and decoding results at https://huggingface.co/csukuangfj/icefall-asr-librispeech-transducer-stateless2-torchaudio-2022-04-19

2022-02-07

Using commit a8150021e01d34ecbd6198fe03a57eacf47a16f2.

The WERs are

	test-clean	test-other	comment
greedy search (max sym per frame 1)	2.67	6.67	--epoch 63 --avg 19 --max-duration 100
greedy search (max sym per frame 2)	2.67	6.67	--epoch 63 --avg 19 --max-duration 100
greedy search (max sym per frame 3)	2.67	6.67	--epoch 63 --avg 19 --max-duration 100
modified beam search (beam size 4)	2.67	6.57	--epoch 63 --avg 19 --max-duration 100

The training command for reproducing is given below:

cd egs/librispeech/ASR/
./prepare.sh
export CUDA_VISIBLE_DEVICES="0,1,2,3"
./transducer_stateless/train.py \
  --world-size 4 \
  --num-epochs 76 \
  --start-epoch 0 \
  --exp-dir transducer_stateless/exp-full \
  --full-libri 1 \
  --max-duration 300 \
  --lr-factor 5 \
  --bpe-model data/lang_bpe_500/bpe.model \
  --modified-transducer-prob 0.25

The tensorboard training log can be found at https://tensorboard.dev/experiment/qgvWkbF2R46FYA6ZMNmOjA/#scalars

The decoding command is:

epoch=63
avg=19

## greedy search
for sym in 1 2 3; do
  ./transducer_stateless/decode.py \
    --epoch $epoch \
    --avg $avg \
    --exp-dir transducer_stateless/exp-full \
    --bpe-model ./data/lang_bpe_500/bpe.model \
    --max-duration 100 \
    --max-sym-per-frame $sym
done

## modified beam search

./transducer_stateless/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir transducer_stateless/exp-full \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 100 \
  --context-size 2 \
  --decoding-method modified_beam_search \
  --beam-size 4

You can find a pretrained model by visiting https://huggingface.co/csukuangfj/icefall-asr-librispeech-transducer-stateless-bpe-500-2022-02-07

Conformer encoder + LSTM decoder

Using commit 8187d6236c2926500da5ee854f758e621df803cc.

Conformer encoder + LSTM decoder.

The best WER is

	test-clean	test-other
WER	3.07	7.51

using --epoch 34 --avg 11 with greedy search.

The training command to reproduce the above WER is:

export CUDA_VISIBLE_DEVICES="0,1,2,3"

./transducer/train.py \
  --world-size 4 \
  --num-epochs 35 \
  --start-epoch 0 \
  --exp-dir transducer/exp-lr-2.5-full \
  --full-libri 1 \
  --max-duration 180 \
  --lr-factor 2.5

The decoding command is:

epoch=34
avg=11

./transducer/decode.py \
  --epoch $epoch \
  --avg $avg \
  --exp-dir transducer/exp-lr-2.5-full \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  --max-duration 100

You can find the tensorboard log at: https://tensorboard.dev/experiment/D7NQc3xqTpyVmWi5FnWjrA

LibriSpeech BPE training results (Conformer-CTC 2)

conformer_ctc2

2022-07-21

It implements a 'reworked' version of CTC attention model. As demenstrated by pruned_transducer_stateless2, reworked Conformer model has superior performance compared to the original Conformer. So in this modified version of CTC attention model, it has the reworked Conformer as the encoder and the reworked Transformer as the decoder. conformer_ctc2 also integrates with the idea of the 'averaging models' in pruned_transducer_stateless4.

The WERs on comparisons with a baseline model, for the librispeech test dataset, are listed as below.

The baseline model is the original conformer CTC attention model trained with icefall/egs/librispeech/ASR/conformer_ctc. The model is downloaded from https://huggingface.co/csukuangfj/icefall-asr-librispeech-conformer-ctc-jit-bpe-500-2021-11-09. This model has 12 layers of Conformer encoder layers and 6 Transformer decoder layers. Number of model parameters is 109,226,120. It has been trained with 90 epochs with full Librispeech dataset.

For this reworked CTC attention model, it has 12 layers of reworked Conformer encoder layers and 6 reworked Transformer decoder layers. Number of model parameters is 103,071,035. With full Librispeech data set, it was trained for only 30 epochs because the reworked model would converge much faster. Please refer to https://tensorboard.dev/experiment/GR1s6VrJRTW5rtB50jakew/#scalars to see the loss convergence curve. Please find the above trained model at https://huggingface.co/WayneWiser/icefall-asr-librispeech-conformer-ctc2-jit-bpe-500-2022-07-21 in huggingface.

The decoding configuration for the reworked model is --epoch 30, --avg 8, --use-averaged-model True, which is the best after searching.

WER	reworked ctc attention	with --epoch 30 --avg 8 --use-averaged-model True		ctc attention	with --epoch 77 --avg 55
test sets	test-clean	test-other	Avg	test-clean	test-other	Avg
ctc-greedy-search	2.98%	7.14%	5.06%	2.90%	7.47%	5.19%
ctc-decoding	2.98%	7.14%	5.06%	2.90%	7.47%	5.19%
1best	2.93%	6.37%	4.65%	2.70%	6.49%	4.60%
nbest	2.94%	6.39%	4.67%	2.70%	6.48%	4.59%
nbest-rescoring	2.68%	5.77%	4.23%	2.55%	6.07%	4.31%
whole-lattice-rescoring	2.66%	5.76%	4.21%	2.56%	6.04%	4.30%
attention-decoder	2.59%	5.54%	4.07%	2.41%	5.77%	4.09%
nbest-oracle	1.53%	3.47%	2.50%	1.69%	4.02%	2.86%
rnn-lm	2.37%	4.98%	3.68%	2.31%	5.35%	3.83%

conformer_ctc2 also implements the CTC greedy search decoding, it has the identical WERs with the CTC-decoding method. For other decoding methods, the average WER of the two test sets with the two models is similar. Except for the 1best and nbest methods, the overall performance of reworked model is better than the baseline model.

To reproduce the above result, use the following commands.

The training commands are:

    WORLD_SIZE=8
    export CUDA_VISIBLE_DEVICES="0,1,2,3,4,5,6,7"
    ./conformer_ctc2/train.py \
    --manifest-dir data/fbank \
    --exp-dir conformer_ctc2/exp \
    --full-libri 1 \
    --spec-aug-time-warp-factor 80 \
    --max-duration 300 \
    --world-size ${WORLD_SIZE} \
    --start-epoch 1 \
    --num-epochs 30 \
    --att-rate 0.7 \
    --num-decoder-layers 6

And the following commands are for decoding:

for method in ctc-greedy-search ctc-decoding 1best nbest-oracle; do
  python3 ./conformer_ctc2/decode.py \
  --exp-dir conformer_ctc2/exp \
  --use-averaged-model True --epoch 30 --avg 8 --max-duration 200 --method $method
done

for method in nbest nbest-rescoring whole-lattice-rescoring attention-decoder ; do
  python3 ./conformer_ctc2/decode.py \
  --exp-dir conformer_ctc2/exp \
  --use-averaged-model True --epoch 30 --avg 8 --max-duration 20 --method $method
done

rnn_dir=$(git rev-parse --show-toplevel)/icefall/rnn_lm
./conformer_ctc2/decode.py \
  --exp-dir conformer_ctc2/exp \
  --lang-dir data/lang_bpe_500 \
  --lm-dir data/lm \
  --max-duration 30 \
  --concatenate-cuts 0 \
  --bucketing-sampler 1 \
  --num-paths 1000 \
  --use-averaged-model True \
  --epoch 30 \
  --avg 8 \
  --nbest-scale 0.5 \
  --rnn-lm-exp-dir ${rnn_dir}/exp \
  --rnn-lm-epoch 29 \
  --rnn-lm-avg 3 \
  --rnn-lm-embedding-dim 2048 \
  --rnn-lm-hidden-dim 2048 \
  --rnn-lm-num-layers 3 \
  --rnn-lm-tie-weights true \
  --method rnn-lm

You can find the RNN-LM pre-trained model at https://huggingface.co/ezerhouni/icefall-librispeech-rnn-lm/tree/main

LibriSpeech BPE training results (Conformer-CTC)

2021-11-09

The best WER, as of 2022-06-20, for the librispeech test dataset is below (using HLG decoding + n-gram LM rescoring + attention decoder rescoring + rnn lm rescoring):

	test-clean	test-other
WER	2.32	5.39

Scale values used in n-gram LM rescoring and attention rescoring for the best WERs are:

ngram_lm_scale	attention_scale	rnn_lm_scale
0.3	2.1	2.2

To reproduce the above result, use the following commands for training:

cd egs/librispeech/ASR/conformer_ctc
./prepare.sh
export CUDA_VISIBLE_DEVICES="0,1,2,3"
./conformer_ctc/train.py \
  --exp-dir conformer_ctc/exp_500_att0.8 \
  --lang-dir data/lang_bpe_500 \
  --att-rate 0.8 \
  --full-libri 1 \
  --max-duration 200 \
  --concatenate-cuts 0 \
  --world-size 4 \
  --bucketing-sampler 1 \
  --start-epoch 0 \
  --num-epochs 90
# Note: It trains for 90 epochs, but the best WER is at epoch-77.pt

# Train the RNN-LM
cd icefall
export CUDA_VISIBLE_DEVICES="0,1,2,3"
./rnn_lm/train.py \
  --exp-dir rnn_lm/exp_2048_3_tied \
  --start-epoch 0 \
  --world-size 4 \
  --num-epochs 30 \
  --use-fp16 1 \
  --embedding-dim 2048 \
  --hidden-dim 2048 \
  --num-layers 3 \
  --batch-size 500 \
  --tie-weights true

and the following command for decoding

rnn_dir=$(git rev-parse --show-toplevel)/icefall/rnn_lm
./conformer_ctc/decode.py \
  --exp-dir conformer_ctc/exp_500_att0.8 \
  --lang-dir data/lang_bpe_500 \
  --max-duration 30 \
  --concatenate-cuts 0 \
  --bucketing-sampler 1 \
  --num-paths 1000 \
  --epoch 77 \
  --avg 55 \
  --nbest-scale 0.5 \
  --rnn-lm-exp-dir ${rnn_dir}/exp_2048_3_tied \
  --rnn-lm-epoch 29 \
  --rnn-lm-avg 3 \
  --rnn-lm-embedding-dim 2048 \
  --rnn-lm-hidden-dim 2048 \
  --rnn-lm-num-layers 3 \
  --rnn-lm-tie-weights true \
  --method rnn-lm

You can find the Conformer-CTC pre-trained model by visiting https://huggingface.co/csukuangfj/icefall-asr-librispeech-conformer-ctc-jit-bpe-500-2021-11-09

and the RNN-LM pre-trained model: https://huggingface.co/ezerhouni/icefall-librispeech-rnn-lm/tree/main

The tensorboard log for training is available at https://tensorboard.dev/experiment/hZDWrZfaSqOMqtW0NEfXKg/#scalars

2021-08-19

(Wei Kang): Result of https://github.com/k2-fsa/icefall/pull/13

TensorBoard log is available at https://tensorboard.dev/experiment/GnRzq8WWQW62dK4bklXBTg/#scalars

Pretrained model is available at https://huggingface.co/pkufool/icefall_asr_librispeech_conformer_ctc

The best decoding results (WER) are listed below, we got this results by averaging models from epoch 15 to 34, and using attention-decoder decoder with num_paths equals to 100.

	test-clean	test-other
WER	2.57%	5.94%

To get more unique paths, we scaled the lattice.scores with 0.5 (see https://github.com/k2-fsa/icefall/pull/10#discussion_r690951662 for more details), we searched the lm_score_scale and attention_score_scale for best results, the scales that produced the WER above are also listed below.

	lm_scale	attention_scale
test-clean	1.3	1.2
test-other	1.2	1.1

You can use the following commands to reproduce our results:

git clone https://github.com/k2-fsa/icefall
cd icefall

# It was using ef233486, you may not need to switch to it
# git checkout ef233486

cd egs/librispeech/ASR
./prepare.sh

export CUDA_VISIBLE_DEVICES="0,1,2,3"
python conformer_ctc/train.py --bucketing-sampler True \
                              --concatenate-cuts False \
                              --max-duration 200 \
                              --full-libri True \
                              --world-size 4 \
                              --lang-dir data/lang_bpe_5000

python conformer_ctc/decode.py --nbest-scale 0.5 \
                               --epoch 34 \
                               --avg 20 \
                               --method attention-decoder \
                               --max-duration 20 \
                               --num-paths 100 \
                               --lang-dir data/lang_bpe_5000

LibriSpeech training results (Tdnn-Lstm)

2021-08-24

(Wei Kang): Result of phone based Tdnn-Lstm model.

Icefall version: caa0b9e942

Pretrained model is available at https://huggingface.co/pkufool/icefall_asr_librispeech_tdnn-lstm_ctc

The best decoding results (WER) are listed below, we got this results by averaging models from epoch 19 to 14, and using whole-lattice-rescoring decoding method.

	test-clean	test-other
WER	6.59%	17.69%

We searched the lm_score_scale for best results, the scales that produced the WER above are also listed below.

	lm_scale
test-clean	0.8
test-other	0.9