[Ffmpeg-devel] AVI to MPG: Major av sync issue

Chris chris
Thu Jun 30 14:36:48 CEST 2005


Sample uploaded to: ftp.mplayerhq.hu/MPlayer/incoming/avi_to_mpeg_sync_issue

I have an avi file which when encoded to mpeg is way out of sync:

using :

ffmpeg -i sample.avi -target dvd -async 50 sample.mpg

ffmpeg version 0.4.9-pre1, build 4757, Copyright (c) 2000-2004 Fabrice
  configuration:  --enable-a52 --enable-gpl --enable-memalign-hack
k --disable-debug
  built on Jun 29 2005 14:32:26, gcc: 3.2.3 (mingw special 20030504-1)
Input #0, avi, from 'sample.avi':
  Duration: 01:41:05.4, start: 0.000000, bitrate: 3 kb/s
  Stream #0.0: Video: mpeg4, yuv420p, 576x240, 25.00 fps
  Stream #0.1: Audio: mp3, 48000 Hz, stereo, 126 kb/s
Assuming PAL for target.
File 'sample.mpg' already exists. Overwrite ? [y/N] y
Output #0, dvd, to 'sample.mpg':
  Stream #0.0: Video: mpeg2video, yuv420p, 720x576, 25.00 fps, q=2-31, 6000

  Stream #0.1: Audio: ac3, 48000 Hz, stereo, 448 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
[mpeg4 @ 0070A780]ac-tex damaged at 16 58.6 bitrate=1483.8kbits/s
[mpeg4 @ 0070A780]Error at MB: 201
[mpeg4 @ 0070A780]concealing 396 DC, 396 AC, 396 MV errors
frame= 1101 q=0.0 Lsize=    8676kB time=39.0 bitrate=1822.0kbits/s
video:6168kB audio:2133kB global headers:0kB muxing overhead 4.512917%

Sample file is truncated from a larger file, hence the error at the end.

The issue here is that the sync is way off. I have tried different values
for async with no success.

The encoding starts and the frame count & time increments but the size
remains at zero. Then at about 10secs the size starts going up and
interestingly the time goes down to 6 secs before incrementing normally.

I suspect it is something to do with the JUNK chunks at the beginning....



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