flac2mp3

#!/usr/bin/env bash

#	flac2mp3.sh
#	Author: William Woodruff
#	------------------------
#	Converts FLAC files into MP3s in bulk.
#	Requires ffmpeg or avconv and GNU bash 4.0.
#	------------------------
#	This code is licensed by William Woodruff under the MIT License.
#	http://opensource.org/licenses/MIT

function usage() {
	echo -e "Usage: $(basename "${0}") [-sdvh] [-j jobs] [directory]"
	echo -e "\t-s - convert files sequentially instead of spawning processes"
	echo -e "\t-d - delete flac files after conversion"
	echo -e "\t-v - be verbose"
	echo -e "\t-h - print this usage information"
	echo -e "\t-j X - Number of jobs to use"
	exit 1
}

function verbose() {
	if [[ "${verbose}" ]]; then
		echo "${*}"
	fi
}

function error() {
	>&2 echo "Fatal: ${*}. Exiting."
	exit 2
}

function installed() {
	cmd=$(command -v "${1}")

	[[ -n  "${cmd}" ]] && [[ -f "${cmd}" ]]
	return ${?}
}

function flac2mp3() {
	flac_file="${1}"
	mp3_file="${flac_file%.flac}.mp3"

	flac_base=$(basename "${flac_file}")
	mp3_base=$(basename "${mp3_file}")

	verbose "Beginning '${flac_base}' -> '${mp3_base}'."
	"${conv}" -y -i "${flac_file}" -b:a 320k "${mp3_file}" &> /dev/null
	verbose "Completed '${mp3_base}'."
}

[[ "${BASH_VERSINFO[0]}" -lt 4 ]] && error "GNU bash 4.0 or later is required"

shopt -s nullglob
shopt -s globstar

if installed ffmpeg; then
	conv=ffmpeg
elif installed avconv; then
	conv=avconv
else
	error "Could not find either ffmpeg or avconv to convert with"
fi

while getopts ":sdvj:" opt; do
	case "${opt}" in
		s ) sequential=1 ;;
		d ) delete=1 ;;
		v ) verbose=1 ;;
		j ) njobs=${OPTARG} ;;
		* )	usage ;;
	esac
done

shift $((OPTIND - 1))

if [[ -n "${1}" ]]; then
	dir="${1}"
	[[ ! -d "${dir}" ]] && error "Not a directory: '${dir}'"
else
	dir="."
fi

flacs=("${dir}"/**/*.flac)

if [[ "${sequential}" ]]; then
	verbose "Converting sequentially."

	for file in "${flacs[@]}"; do
		flac2mp3 "${file}"
	done
else
	verbose "Converting in parallel."
	if installed "parallel"; then
        export -f flac2mp3 verbose
        export conv
		if [[ -z "${njobs}" ]]; then
			printf '%s\n' "${flacs[@]}" | parallel -j+0 -q flac2mp3
		else
			printf '%s\n' "${flacs[@]}" | parallel -j"${njobs}" -q flac2mp3
        fi
	else
		verbose "'parallel' is not installed, falling back to forking. Job control will NOT work in this mode."
		for file in "${flacs[@]}"; do
			flac2mp3 "${file}" &
		done
		wait
	fi
fi

if [[ "${delete}" ]]; then
	verbose "Deleting old FLACs..."
	rm -rf "${flacs[@]}"
	verbose "done."
fi

verbose "All done. ${#flacs[@]} files converted."