ffmpeg.split

#!/bin/bash
# Only one stream A/V - BE CAREFULL - This keep only one stream AND DELETE OTHERS
ffmpeg -i largefile.mp4 -t 00:50:00 -c copy smallfile1.mp4 \
-ss 00:50:00 -c copy smallfile2.mp4
# This will create smallfile1.mp4, ending at 50 minutes into the video of largefile.mp4, 
# and smallfile2.mp4, starting at 50 minutes in and ending at the end of largefile.mp4.

# Multi-streams A/V/SUB
ffmpeg -i 'BIG_VIDEO_FILE_WITH_MUTLI_AUDIO.mkv' -t 00:51:00  -c copy -map 0 "SMALL_VIDEO_FILE_WITH_MULTI_AUDIO_part1.mkv" \
-ss 00:50:00 -c copy -map 0 "SMALL_VIDEO_FILE_WITH_MULTI_AUDIO_part2.mkv"
# This will create VIDEO_part1.mkv, ending at 50 minutes into the video of BIG_VIDEO_FILE_WITH_MUTLI_AUDIO.mkv, 
# and VIDEO_part2.mkv, starting at 50 minutes in and ending at the end of BIG_VIDEO_FILE_WITH_MUTLI_AUDIO.mkv,
# one minute is added to avoid loosing data
# all streams should be kept during the process


# STREAM-REMAPING
https://trac.ffmpeg.org/wiki/Map