[FFmpeg-user] concat muxer with two video files with two different resolutions

Nicolas George george at nsup.org
Sun Apr 13 20:15:45 CEST 2014

Le duodi 22 germinal, an CCXXII, Ben Mesander a écrit :
>   Today I tried to concatenate two h.264 video files with the concat muxer.
> The two files have differing input resolutions (848x480 and 1280x720). I
> would like the resulting video to be 640x480. I used today's static 32-bit
> build from ffmpeg.org.

> In the resulting output mp4 file, the first video file appears as the
> input, correctly sized to 640x480. The second video file shows up as mostly
> grey with random green macroblocks and flickery random pixels here and
> there.
> So it appears an (undocumented? I don't see it) feature of the concat muxer
> is the input files must be the same resolution, so this approach simply
> won't work?

I can reproduce the problem. I suspect it has something to do with the
global extradata, I must look into it and understand what is going on.

You probably do not want to create a file that has resolution changes in the
middle: you will be transcoding. Therefore, I suspect the concat filter
would be more adapted to your needs.


  Nicolas George
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