ffmpeg:无法剪切 avi 电影

Question

我正在使用 ffmpeg 剪切视频文件:

ffmpeg -<InputFile> -ss 00:00:00 -t 00:00:30 <OutputFile>

不包括 *.avi 格式的不同文件格式是可以的。对于 avi 电影，ffmpeg 显示视频被截断，但输出文件包含完整视频(不截断)。
有人知道解决问题的可能方法吗？

这里将命令输出转换为 avi 文件:

FFmpeg version SVN-r26402, Copyright (c) 2000-2011 the FFmpeg developers
  built on Feb  1 2011 02:54:36 with gcc 4.4.5
  configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab
  libavutil     50.36. 0 / 50.36. 0
  libavcore      0.16. 1 /  0.16. 1
  libavcodec    52.108. 0 / 52.108. 0
  libavformat   52.93. 0 / 52.93. 0
  libavdevice   52. 2. 3 / 52. 2. 3
  libavfilter    1.74. 0 /  1.74. 0
  libswscale     0.12. 0 /  0.12. 0
  libpostproc   51. 2. 0 / 51. 2. 0
[mpeg4 @ 0x91e7e10] Invalid and inefficient vfw-avi packed B frames detected

Seems stream 0 codec frame rate differs from container frame rate: 30000.00 (30000/1) -> 25.00 (25/1)
Input #0, avi, from '/home/mightymeeting/Videos/tam-19.avi':
  Duration: 00:04:43.32, start: 0.000000, bitrate: 564 kb/s
    Stream #0.0: Video: mpeg4, yuv420p, 352x208 [PAR 1:1 DAR 22:13], 25 fps, 25 tbr, 25 tbn, 30k tbc
    Stream #0.1: Audio: mp3, 32000 Hz, 2 channels, s16, 80 kb/s
[buffer @ 0x91e6ed0] w:352 h:208 pixfmt:yuv420p
Output #0, avi, to 'out.avi':
  Metadata:
    ISFT            : Lavf52.93.0
    Stream #0.0: Video: mpeg4, yuv420p, 352x208 [PAR 1:1 DAR 22:13], q=2-31, 200 kb/s, 25 tbn, 25 tbc
    Stream #0.1: Audio: mp2, 32000 Hz, 2 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop encoding
[mpeg4 @ 0x91e7e10] Invalid and inefficient vfw-avi packed B frames detected
frame= 7082 fps=999 q=2.0 Lsize=    7513kB time=30.02 bitrate=2049.8kbits/s dup=0 drop=1    
video:7079kB audio:235kB global headers:0kB muxing overhead 2.718192%

Answer 1

听起来这可能是一个 DivX 文件。尝试

ffmpeg -i INPUT.avi -c copy -ss 00:00:00 -t 00:00:30 -bsf:v mpeg4_unpack_bframes OUTPUT.avi

来自 documentation

DivX-style packed B-frames are not valid MPEG-4 and were only a workaround for the broken Video for Windows subsystem. They use more space, can cause minor AV sync issues, require more CPU power to decode (unless the player has some decoded picture queue to compensate the 2,0,2,0 frame per packet style) and cause trouble if copied into a standard container like mp4 or mpeg-ps/ts, because MPEG-4 decoders may not be able to decode them, since they are not valid MPEG-4.