diff --git a/icefall/.utils.py.swp b/icefall/.utils.py.swp
index 5ac65ead6..4d362b1df 100644
Binary files a/icefall/.utils.py.swp and b/icefall/.utils.py.swp differ
diff --git a/icefall/utils.py b/icefall/utils.py
index caaba6aea..04482b8af 100644
--- a/icefall/utils.py
+++ b/icefall/utils.py
@@ -191,7 +191,15 @@ def encode_supervisions(
     returned tensor and list of strings are guaranteed to be consistent with
     each other.
     """
+    try: start_frame = supervisions["start_frame"]
+    except: start_frame = [0 for i in range(len(supervisions["cut"]))]
 
+    try: num_frames = supervisions["num_frames"]
+    except:
+        num_frames = []
+        for supervision in supervisions['cut']:
+            try: num_frames.append(supervision.tracks[0].cut.recording.num_samples)
+            except: num_frames.append(supervision.recording.num_samples)
     supervision_segments = torch.stack(
         (
             supervisions["sequence_idx"],