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

[张弘强]

That because the most of Mobile Phone records the video with bad quality camra, and the first few frames very dark
not the the transposing makes image broken.

Regards,
--------------------------------------------------------------------------------------------------------------------------------------
Freeman
Mobile: 13811178263
E-Mail: zhanghongqiang at xiaomi.com


________________________________________
发件人: libav-user-bounces at ffmpeg.org [libav-user-bounces at ffmpeg.org] 代表 Carl Eugen Hoyos [cehoyos at ag.or.at]
发送时间: 2013年3月23日 4:23
收件人: libav-user at ffmpeg.org
主题: Re: [Libav-user]    答复: How to extract a H264 video frame (container is 3GPP/MP4) into a JPG File (with libavformat and libavcode) ?

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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