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I have a large directory of small video clips taken with a cell phone. I've been able to use mp4box to concatenate them into a single file nicely EXCEPT if they are different aspect ratio. In this case it is when I try to combine a video taken with the phone upright vs. taken side ways.

mp4box.exe -cat long.mp4 -cat wide.mp4 broken.mp4

mp4box is saying:

WARNING: Concatenating track ID 1 with different SPS - result file might be brok en

When I play the video it clearly blocky and corrupted.

Is there a way to merge these files with mp4box or any other command line tool and force a single (probably 16:9) format?

Also even better, since I am doing this in an automated fashion, it would be nice to have a way to just force all of the output video to a single format rather than have to perform special actions on just the upright videos.

I've tried resetting or forcing the SPS, but I can't seem to get it right.

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What you want to do is not possible without re-encoding the video. Is that an option? – slhck Jul 24 '13 at 5:52
Sure I could do that too. – awl Jul 25 '13 at 0:33

You could try recent versions of ffmpeg (ffmpeg wiki: How to concatenate media files ) although you may have to resize the video...

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