Correctly splitting an avi file

There's a dedicated tool to do this, avimerge:

avimerge -o cd.avi -i cd1.avi cd2.avi

If not installed, install transcode: Avimerge is part of transcode package: https://manpages.debian.org/jessie/transcode/avimerge.1.en.html http://manpages.ubuntu.com/manpages/bionic/man1/avimerge.1.html

mplayer comes with an midentify utility that does mostly what you want.

The output looks like variable assignments, so it is pretty easy to use in scripts/simple to parse.

If midentify isn't installed with your mplayer package, you might have an midentify.sh script in /usr/share/mplayer or something like that. If not, midenfify just runs mplayer with a specific set of arguments:

#!/bin/sh
#
# This is a wrapper around the -identify functionality.
# It is supposed to escape the output properly, so it can be easily
# used in shellscripts by 'eval'ing the output of this script.
#
# Written by Tobias Diedrich <ranma+mplayer@tdiedrich.de>
# Licensed under GNU GPL.

if [ -z "$1" ]; then
        echo "Usage: midentify.sh <file> [<file> ...]"
        exit 1
fi

mplayer -vo null -ao null -frames 0 -identify "$@" 2>/dev/null |
    sed -ne '/^ID_/ {
                      s/[]()|&;<>`'"'"'\\!$" []/\\&/g;p
                    }'

The -ao, -vo and -frames parameters prevent mplayer from actually playing the clip. The rest is just formatting.

Example:

$ midentify some_random.avi 
ID_VIDEO_ID=0
ID_AUDIO_ID=0
...
ID_VIDEO_BITRATE=258488
ID_VIDEO_WIDTH=320
ID_VIDEO_HEIGHT=240
ID_VIDEO_FPS=29.917
...
ID_LENGTH=4216.76
...
ID_AUDIO_BITRATE=64000
ID_AUDIO_RATE=22050
...