[Libav-user] 答复: How to extract a H264 video frame (container is 3GPP/MP4) into a JPG File (with libavformat and libavcode) ?

Carl Eugen Hoyos cehoyos at ag.or.at
Fri Mar 22 21:23:40 CET 2013

张弘强 <zhanghongqiang at ...> writes:

> ffmpeg -i video_clip.3gp -vframes 1 -ss 00:00:01 
> -vf "transpose=1" output.jpg 
> (the first frame is not good enough)

Do you mean the first frame is black / does not show the 
information you would like to have in your output jpg or 
is there something wrong with the transoding like for 
example a non-keyframe gets encoded and the output 
image is broken? If that is the case, please provide 
your complete, uncut console output and a sample.

Please do not top-post here, Carl Eugen

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