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• How to split ffmpeg output into multiple files ?

  15 novembre 2020, par Genius Billionaire

  What I want to happen : the equivalent of this : split -n 4 output.mp4, which generates 4 files. Only the first file is "valid mp4" that you can play. The other 3 files rely on the previous file.

  


  A similar request can be seen here : https://lists.ffmpeg.org/pipermail/ffmpeg-user/2013-May/015090.html

  


  Why I want this to happen : running FFMPEG in the browser, which means 1) file size limit, 2) I don't have the Linux command split to help me out, just FFMPEG. If I can get FFMPEG to output files of X MB each, I can iteratively delete files as soon as I've read them.

  


  EDIT : as a commenter asked, yes it is possible to run several ffmpeg commands if necessary.

  


  The right solution is not using segments. The following example command generates several 4 valid mp4 files. That's not exactly what I want.
ffmpeg -i ../flv.flv -segment_time 5 -f segment -t 20 %d.mp4

  


  This other solution also does not work (it's the same output as previous incorrect solution) :

  


  ffmpeg -i ../flv.flv -ss 00:00:00 -t 5 1.mp4

  


  ffmpeg -i ../flv.flv -ss 00:00:05 -t 5 2.mp4

  


• ffmpeg : fast video split by encoding only missing keyframes and copying the rest

  29 janvier 2023, par Eduardo Poço

  I am splitting a video in many files, removing the silent periods. The script is ready to detect the voiced parts, split and concat.

  


  At first, it thought copying the frames (-c copy) would be faster, but if a starting time of a part is not a keyframe, the video gets messed and some frames freeze until another keyframe appears. But reencoding each split file, although working, takes a long time.

  


  So, I was wondering if it is possible to reencode only the moments whose frames lost its keyframe, while copying everything so on. Is there a ffmpeg option for suck a task, or is there a way to differentiate those frames and treat them differently when splitting the file ?

  


  After reading some articles and documentation, that is how I understand what I am observing. Please, correct me if I misunderstood how ffmpeg works when splitting a file starting from a timestamp without a keyframe.

  


• Is there an elegant way to split a file by chapter using ffmpeg ?

  6 février 2017, par Kattern

  In this page, Albert Armea share a code to split videos by chapter using ffmpeg. The code is straight forward, but not quite good-looking.

  ffmpeg -i "$SOURCE.$EXT" 2>&1 | grep Chapter | sed -E "s/ *Chapter #([0-9]+.[0-9]+) : start ([0-9]+.[0-9]+), end ([0-9]+.[0-9]+)/-i \"$SOURCE.$EXT\" -vcodec copy -acodec copy -ss \2 -to \3 \"$SOURCE-\1.$EXT\"/" | xargs -n 11 ffmpeg

  Is there an elegant way to do this job ?