problem using FFMPEG to extract h264 clip

Hongfeng Wang

a 10min video is generated by DM368-DVSDK4.02's encode demo 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 120 -i 20111101_153000.264 -t 10 -vcodec copy 201101153500.mp4

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 same result.

The video has an IDR frame in every 20 frames.

Thanks for your help.

over 14 years ago

0 Hongfeng Wang over 14 years ago

Genius 3925 points

I have made some progress on this.

If I use -ss option on the output instead of input, on FFMPEG0.7.2-4, it works correctly.

However, on FFMPEG 0.5.4-4, it will generate a clip of length offset+duration, the first $(offset) seconds of video are just still, then it starts to move on the $(offset) second.

0 Hongfeng Wang over 14 years ago in reply to Hongfeng Wang

Genius 3925 points

all right, I got it.

I downloaded newer version ffmpeg from squeeze-backports, now it's working as expected, except that I need to use -vframes option instead of -t.

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problem using FFMPEG to extract h264 clip