ffmpeg -i source-file.foo -ss 0 -t 600 first-10-min.m4v
will work but is slow. Solution:
ffmpeg -ss 00 -t 00:01:0.0 -i source.mp4 -vcodec copy -acodec copy result.mp4
Will split the source.mp4 from the beginning to the first 60 seconds and save it in result.mp4.
