How to segment a video and then concatenate back into original one with ffmpeg

Question

I am surveying on distributed video transcoding with FFmpeg. I have found that there is a good script on https://github.com/nergdron/dve/blob/master/dve.

The script

Answer 1

The segment muxer, by default, preserves input timestamps. And the way that the concat demuxer works is that it adds the relative timestamp of incoming files to the net duration processed so far. e.g. If first file is 10 seconds, and second file is 5 seconds but with a start time of 10 seconds. Then the first frame of the 2nd file in the output will have a timestamp of 20 seconds. This, I believe, is leading to the AVI warning.

Also keeping in mind that the segment muxer can create the concat list for you, use

ffmpeg -fflags +genpts -i Test.avi -map 0 -c copy -f segment -segment_format avi -segment_list Test.ffcat -reset_timestamps 1 -v error chunk-%03d.seg

and then

ffmpeg -y -v error -i Test.ffcat -map 0 -c copy output.avi