Cut up mp4 file into chunks without reencoding/loss of quality?

[Xirix]

I have some quite large mp4 files (5-6 hours+) that I'd like to cut into either 30 minute or 1 hour chunks, without reencoding them. Are there any programs that can automate this process?

[poisondeathray]

mp4box . Make sure you download a very recent mp4box build from GPAC, because older mp4box builds did not work properly

The basic syntax is -split (in seconds)

e.g.

mp4box -split 1800 "input.mp4"

would produce

input_001.mp4
input_002.mp4
input_003.mp4
.
.
.



They won't be EXACTLY 1800sec for most types of files - because the splits have to be on GOP boundaries on Keyframes. So it might be a second or so off each cut depending on the source file and GOP configuration , but the output files will not have missing frames or overlaps (ie. if you re-join the segments, you will have the original)



To do it in batch file (e.g. process all the MP4 files in a directory)

for %%a in ("*.mp4") do "mp4box.exe" -split 1800 "%%a" 
pause