Opened 8 years ago
Closed 8 years ago
#6319 closed defect (worksforme)
Raw audio is x2 times slower than it should be
Reported by: | Thomas Thomas | Owned by: | |
---|---|---|---|
Priority: | normal | Component: | undetermined |
Version: | git-master | Keywords: | |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description
Summary of the bug: when converting mp3 file to raw audio file of format s16l and then converting it back to mp3, audio is slower x2 times.
How to reproduce:
ffprobe 1.mp3 ffmpeg -i 1.mp3 -y -f s16le 1.hex ffmpeg -f s16le -i 1.hex -y 1.mp3 ffprobe 1.mp3
This is latest FFMPEG version. Output of ffprobe is:
Input #0, mp3, from '1.mp3': Metadata: encoder : Lavf57.57.100 Duration: 00:00:03.02, start: 0.023021, bitrate: 128 kb/s Stream #0:0: Audio: mp3, 48000 Hz, stereo, s16p, 128 kb/s Metadata: encoder : Lavc57.66
and
Input #0, mp3, from '1.mp3': Metadata: encoder : Lavf57.57.100 Duration: 00:00:06.56, start: 0.025057, bitrate: 64 kb/s Stream #0:0: Audio: mp3, 44100 Hz, mono, s16p, 64 kb/s
If I change it to
ffmpeg -f s16le -ar 48000 -i 1.hex -y -b:a 128k 3.mp3
output frequency and bitrate are fixed, but audio is still x2 times slower (duration is still 6 seconds instead of 3). It should be 3.
I think there's no need to upload example mp3, because this bug appears with any mp3.
Change History (2)
comment:1 by , 8 years ago
comment:2 by , 8 years ago
Keywords: | raw-audio removed |
---|---|
Priority: | critical → normal |
Resolution: | → worksforme |
Status: | new → closed |
Version: | 3.2.4 → git-master |
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Raw files contain no metadata to populate stream contexts, so those have to be specified. If not specified, ffmpeg falls back on default values. In this case, during conversion from raw to mp3, it's treating the input as mono, hence treating it as double the actual length.
Your third command should be
ffmpeg -f s16le -ar 48000 -ac 2 -i 1.hex -y 1.mp3