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I am trying to combine 2 or more .mp4 videos into a single video (concatenation). But I am getting timestamps errors (with ffmpeg concat demuxer protocol). The videos are very similar (same resolution, fps, etc.), so I'm not sure what is causing this. I am open to trying different tools (hopefully something that runs on linux).

Apparently they are slightly different in some way.

How can I concatenate them, without losing quality?

If you need more information please tell me what command I should run to print the required details.

Update: I am trying to concatenate 4 files. I am using the command:

ffmpeg -f concat -i list.txt -c copy full.mp4

where list.txt is a text file with the contents:

file 1.mp4
file 2.mp4
file 3.mp4
file 4.mp4

By request I executed the same command with -report as added as the first option. This produced a large log file (110 MB) that you can see here: http://www.filedropper.com/ffmpeg-20180606-024711.

I also ran ffprobe on each file, and uploaded the results here:

  1. ffprobe 1.mp4: https://justpaste.it/64pih
  2. ffprobe 2.mp4: https://justpaste.it/6r4ig
  3. ffprobe 3.mp4: https://justpaste.it/77iij
  4. ffprobe 4.mp4: https://justpaste.it/3xdoi
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  • Run the same command with -report added and share the report file
    – Gyan
    Jun 5, 2018 at 6:36
  • @Gyan The report file is ~ 110 MB (is that normal?). I uploaded it here filedropper.com/ffmpeg-20180606-024711.
    – a06e
    Jun 6, 2018 at 0:56
  • That's too large. Share output of ffprobe file and ffprobe file2 as well as your command.
    – Gyan
    Jun 6, 2018 at 16:46
  • @Gyan Please see edits in the question. I added the requested information.
    – a06e
    Jun 6, 2018 at 21:57

1 Answer 1

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Your 2nd file is different. You can re-encode it this way,

ffmpeg -i 2.mp4 -map 0:a -map 0:v
       -c:v libx264 -profile:v main -c:a aac -ar 48000 
       -video_track_timescale 2500   2-new.mp4

Depending on how the video in the other files was encoded, you may need to try adding -bf 1 or -bf 0.

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  • Thanks. The resulting file is almost half-the size (and smaller than what I expect from similar files of similar duration). Is this lossless?
    – a06e
    Jun 7, 2018 at 6:31
  • 1
    It uses CRF 23 as default encoding. Add -crf 18 for visually lossless result
    – Gyan
    Jun 7, 2018 at 6:38

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