#!/bin/bash

#rm FLAC_VOL/*.flac

threads=$(nproc)
i=1
for F in FLAC/*.flac; do
	NAME=${F#*/}
	NAME=${NAME%*.flac}

	SUM=$(metaflac --show-md5sum $F)
	VOLF=FLAC_VOL/${NAME}_vol.flac
	if [[ -f $VOLF ]]; then
		VOLSUM=$(metaflac --show-tag=ORGSUM $VOLF)
		VOLSUM=${VOLSUM#*=}
		if [[ $SUM == $VOLSUM ]]; then
			continue
		fi
	fi

	#pv -N ${F} FLAC/${F} | ffmpeg -threads 4 -v warning -i pipe:0 -af 'volume=-4dB' -y -compression_level 12 $VOLF
	pv -c -N ${NAME} ${F} | ffmpeg -threads 4 -v fatal -i pipe:0 -af 'volume=-6dB' -metadata ORGSUM=${SUM} -y $VOLF &

	((i++))

	if (( i > threads )); then
		i=1
		wait
	fi
done

wait