If somebody is looking for ReplayGain with DietPi there are some information here:
apt install flac
#!/bin/bash
MUSIC="/mnt/dietpi_userdata/Music"
find "$MUSIC" -type f -iname "*.flac" -print0 | \
xargs -0 -n1 -P$(nproc) bash -c '
for file; do
if ! metaflac --list "$file" | grep -q "REPLAYGAIN_TRACK_GAIN"; then
echo "Adding ReplayGain: $file"
metaflac --add-replay-gain "$file"
else
echo "Skipping: $file"
fi
done
' _
Have not tested it yet. Will do that hopefully this WE
Torben