[FFmpeg-trac] #1755(avformat:new): Audio becomes silent on some avi files. (This problem is reproduced during 1x play and seek)
FFmpeg
trac at avcodec.org
Thu Sep 20 09:34:15 CEST 2012
#1755: Audio becomes silent on some avi files. (This problem is reproduced during
1x play and seek)
-------------------------------------+-------------------------------------
Reporter: Heesuk Jung | Type: defect
Status: new | Priority: normal
Component: avformat | Version: 0.11.1
Keywords: Grouped | Blocked By:
Audio PTS | Reproduced by developer: 1
Blocking: |
Analyzed by developer: 1 |
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Summary of the bug:
Audio become silent before playback reach end of file.
Video end at about 31 sec but audio stopped about 12 sec.
I reviewed audio and video PTS information using ffprobe tool.
Please refer the PTS plotting graph as below.
(Notice! Recommend download of PTS plotting file because of Google docs
excel inter-operability)
* PTS plotting link :
https://docs.google.com/open?id=0B6r7ZfWFIypCbnRtVlFTVVA0cEU
* Problematic file link :
https://docs.google.com/open?id=0B6r7ZfWFIypCeXB3b2J5S1NDMzQ
My Analysis of PTS
- Video PTS is OK.
- Audio PTS is NG.
- Whole timeline of this media file is about 31 sec but audio pts has
about 12 sec timeline.
- Also values of Audio PTS are grouped as special pattern.
- Simplified Audio PTS pattern : 0, 0, 0, 1, 1, 2, 2, ……. , N/3
- Simplified Video PTS pattern : 0, 1, 2, …. , N
-> The shape of audio PTS make 2 problem.
1) Audio stop early. Because audio PTS by ffmpeg have 12 sec but real
audio has 30 sec.
2) Seek does not work after 12 sec.
- My co-worker checked audio PTS information of problematic based on
avidemux and Audio PTS is just OK.
- And so I request that FFmpeg team inspect this problem.
How to reproduce:
% ffplay
016_avi_mpeg4_sp[720 at 24fps]_aac[2ch_128kbps_44.1khz].avi[MV]_origin.avi
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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1755>
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