Extract and Add AC3 audio stream

Extract and Add AC3 Audio.cmd

::  Extract main audio track as AC3 for mkvtoolnix adding
::  Opens mvktoolnix with original mkv file to then add ac3 manually
::  Recommended: create Scripts folder in your user folder and then copy MKVToolnix portable there
::  This will retain all original video/audio/subtitle streams and make ac3 versions of 
::  all audiostreams in mka form and then open mkvtoolnix with said files to then multiplex.
::  seamonkey420
::  1/14/2025
::------------
setlocal EnableExtensions DisableDelayedExpansion

:: set mkvtoolnix-gui.exe location: update to where you have yours installed
set _mkvtool=C:\Users\username\Scripts\MKVToolNix\mkvtoolnix-gui.exe

::get path filename and extensions as variables
set _path=%~dp1
set _name=%~n1
set _ext=%~x1

ffmpeg -i "%_name%%_ext%" -map 0:a -c:a ac3 -b:a 640k -center_mixlev 0.707 "%_name%".mka

:: launches mkvtoolnix-gui with original file and ac3 audio stream
:: setting in mkvtoolnix: When adding files via drag and drop/copy and paste: 
::                        create one new multiplex settings add all files there
start "" "%_mkvtool%" %1 "%_path%%_name%.mka"
exit