Lossless EBU R128 audio normalization with Matroska tags

replaygain.sh

#!/bin/sh
set -e
mkvdir=$(mktemp -d)
gaindir=$(mktemp -d)

for i in "$@"; do
        ffmpeg -v error -i "$i" -vn -c:a copy "$gaindir"/"$(basename "$i")".mkv
done

bs1770gain --track-tags -o "$mkvdir" -- "$gaindir"/*
mv "$mkvdir"/* .
rm "$gaindir"/*
rmdir "$gaindir"
rmdir "$mkvdir"