I got a mp4 video. I just want to split it in 4GB file parts using ffmpeg (to make it writeable on FAT32).

C:\ffmpeg\ffmpeg.exe -i "%NAME%.mp4" -n -t %LENGTH% -codec copy "%NAME%_1.mp4"
C:\ffmpeg\ffmpeg.exe -ss %LENGTH% -i "%NAME%.mp4" -n -codec copy "%NAME%_2.mp4"
  • The original file's overall bitrate is 9450 Kbps.
  • The first output's overall bitrate is 10.1 Mbps.
  • The second output's overall bitrate is 8727 Kbps.

I guess that the bitrate of the original video is variable and not equally distributed, is that right ?

How can I fix it (in a batch that would be great)? May I convert first the original video to constant bitrate?

Thanks for help guys !

  • Is the problem that the two parts don't land at less than 4GB every time? – Paul Jul 31 '14 at 1:30
  • Yes because I calculate the length of outputs based on bitrate. In the given example, the first output would be around 4,25GB. – kiwixz Jul 31 '14 at 1:33
  • Think about using the segmenter in ffmpeg. ffmpeg segmenter documentation Changing the bitrate will require a re-encode. Why not just undershoot to 3GB? – dstob Jul 31 '14 at 15:54
  • I'm actually not confident in re-encode (afraid of quality loss). So I'll undershoot, as you said. But I'm still looking for an answer if someone have one :) – kiwixz Jul 31 '14 at 18:51

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.