in what case the Whisper will output an empty srt file?

[lpf1143]

I try to transcribe one video, but after processing, I got an "empty" srt file looks like this. The video is in English btw

62
00:01:22,000 --> 00:01:22,000
.

63
00:01:22,000 --> 00:01:22,000
.

64
00:01:22,000 --> 00:01:22,000
.

65
00:01:22,000 --> 00:01:22,000
.

66
00:01:22,000 --> 00:01:22,000
.

67
00:01:22,000 --> 00:01:22,000
.

68
00:01:22,000 --> 00:01:22,000
.

69
00:01:22,000 --> 00:01:22,000
.

70
00:01:22,000 --> 00:01:22,000
.

71
00:01:22,000 --> 00:01:22,000
.

72
00:01:22,000 --> 00:01:22,000
.

73
00:01:22,000 --> 00:01:22,000
.

74
00:01:22,000 --> 00:01:22,000
.

75
00:01:22,000 --> 00:01:22,000
.

[RickArcher108]

Sometimes when this happens, I try again and it works, or I try transcribing the mp4 instead of the mp3 and it works.

[lpf1143]

Sometimes when this happens, I try again and it works, or I try transcribing the mp4 instead of the mp3 and it works.

actually I got multiple mp4 files from the same site (zoom actually, so I assume they have the same encoding?), two mp4 from one presenter ans two mp4 from the other one. The funny thing is the two mp4 from presenter A all lead to empty output file, no matter I transcribe the mp4 directly or extract the audio to m4a or aac, and I tried multiple time btw. The two mp4 from presenter B work perfectly.