[FFmpeg-user] problem using FFMPEG -ss to extract segment of h264 video

[Hongfeng Wang]

Hi, guys:

I got a 10min video is generated by DM368-DVSDK4.02's encode program. The 264 file could be played by Ubuntu movie player.

If I convert the whole clip to mp4 using ffmpeg, it works without any problem. But if I try to extract a fraction of the video, it always run into "missing picture in access unit" problem, and only generates a 1 second clip, which is the end of whole video.

ffmpeg -r 20.2 -ss 300 -i 20111101_153000.264 -t 10 -vcodec copy 201101153500.mp4

FFmpeg version SVN-r0.5.4-4:0.5.4-1, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --extra-version=4:0.5.4-1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libdirac --enable-libgsm --enable-libopenjpeg --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --disable-vhook --enable-runtime-cpudetect --extra-cflags=-marm -fPIC -DPIC --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libfaad --enable-libdc1394 --enable-shared --disable-static
  libavutil     49.15. 0 / 49.15. 0
  libavcodec    52.20. 1 / 52.20. 1
  libavformat   52.31. 0 / 52.31. 0
  libavdevice   52. 1. 0 / 52. 1. 0
  libavfilter    0. 4. 0 /  0. 4. 0
  libswscale     0. 7. 1 /  0. 7. 1
  libpostproc   51. 2. 0 / 51. 2. 0
  built on Sep 18 2011 15:55:02, gcc: 4.4.5
[NULL @ 0x49170]missing picture in access unit

Seems stream 0 codec frame rate differs from container frame rate: 40.40 (202/5) -> 20.20 (202/10)
Input #0, h264, from '20111101_153000.264':
  Duration: N/A, bitrate: N/A
    Stream #0.0: Video: h264, yuv420p, 1920x1080, 20.20 tbr, 1200k tbn, 40.40 tbc
Output #0, mp4, to '201101153500.mp4':
    Stream #0.0: Video: 0x0000, yuv420p, 1920x1080, q=2-31, 90k tbn, 20.20 tbc
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
[NULL @ 0x49170]missing picture in access unit
frame=   20 fps=  0 q=-1.0 Lsize=     280kB time=0.99 bitrate=2313.3kbits/s    
video:279kB audio:0kB global headers:0kB muxing overhead 0.314991%


the FFMPEG I used is FFmpeg version SVN-r0.5.4-4:0.5.4-1 from Debain ARMEL packages.
I also tried  FFMPEG0.7.2-4 on my Ubuntu machine, which has the same result.
I tried different values for -ss option, from 5 to 300, all the same.
The video has an IDR frame for every 20 frames.

Thanks!

Hongfeng Wang