mkv-remove-language

#!/bin/bash
#
# Version 3
#
# (C) 2016 Daniel Faust <hessijames@gmail.com>
#
# A BASH script that removes the audio track with the specified language from a matroska file.
#
# Requires mkvmerge
#
# Usage:
# chmod +x mkv-remove-language
# ./mkv-remove-language "My File.mkv" "eng"
#
# This will create a new file called "My File [without eng].mkv".
#
# For batch processing all .mkv files in the current directoy
# copy mkv-remove-language to a directory in your PATH and execute:
#
# find -iname "*.mkv" -exec mkv-remove-language '{}' "lang" \;


if [[ "$1" == "" ]] || [[ "$1" == "--help" ]] || [[ "$1" == "-h" ]]; then
	echo
	echo "Process single file:"
	echo "mkv-remove-language file.mkv lang"
	echo
	echo "Process multiple files:"
	echo "find -iname \"*.mkv\" -exec mkv-remove-language '{}' \"lang\" \;"
	echo
	exit
fi


hash mkvmerge 2>/dev/null || { echo >&2 "Error: Command mkvmerge not found"; exit 1; }


file_name=$1
remove_language=$2

IFS='
'

tracks=$(LANG=en_US.utf8 LANGUAGE=en_US.utf8 mkvmerge --identify-verbose "$file_name" | tail --lines=+2)

track_ids_string=""
found_languages=()
for track in $tracks; do
	track_id=""
	[[ "$track" =~ Track\ ID\ ([0-9]+) ]] &&
		track_id=${BASH_REMATCH[1]}
	[[ "$track" =~ language:([a-z]+) ]] &&
		language=${BASH_REMATCH[1]}
	[[ "$track" =~ Track\ ID\ [0-9]+:\ ([a-z]*) ]] &&
		track_type=${BASH_REMATCH[1]}

	if [[ "$track_id" == "" ]]; then
		continue
	fi

	if [[ "$track_type" != "audio" ]]; then
		continue
	fi

	if [[ "$language" == "$remove_language" ]]; then
		track_ids_string="$track_ids_string,$track_id"
	else
		found_languages+=("$language")
	fi
done
track_ids_string=${track_ids_string:1} # remove first comma

if [[ "$track_ids_string" != "" ]]; then
	mkvmerge -o "${file_name%.*} [without $remove_language].mkv" --audio-tracks "!$track_ids_string" "$file_name"
else
	echo "Can't find languge \"$remove_language\", doing nothing"
	echo "Available languages are:"
	for language in "${found_languages[@]}"; do
		echo "  $language"
	done
fi