https://virtualtam.flibidi.net/index.php/2018/02/08/backup-compress-and-normalize-audio-files-from-a-boss-rc-30-loop-station/

rc30dump.sh

#!/bin/bash
#
# Backup, compress and normalize audio files from a BOSS RC-30 Loop Station
#
# Sequence:
# - dump audio content from the RC-30
# - encode and normalize audio
#
# Dependencies:
# - your favourite external storage mounting tool,
#   - file managers: Dolphin, Nautilus, PCManFM, etc.
#   - CLI: gvfs, pmount, udiskie, etc.
# - rsync
# - ffmpeg for audio encoding and normalization
#
# Author: VirtualTam    <[email protected]>

VOLUME=01

MOUNTPOINT=/run/media/${USER}/BOSS_RC-30
WAV_DIR=wav
WAV_SUBDIR=${WAV_DIR}/${VOLUME}
FORMAT=ogg

function dump() {
    # Dumps the looper's tracks
    # ${1}: RC-30 mountpoint
    # ${2}: directory to copy WAV files to
    if [[ ! -d ${1} ]]; then
        echo "Dump: ${1} is not mounted"
        return
    fi
    rsync \
        -a \
        -v \
        --perms \
        --chmod=D2775,F664 \
        --prune-empty-dirs \
        ${1}/ROLAND/WAVE/ ${2}/
}

function max_volume() {
    # Computes a track's peak volume
    # ${1}: input file
    ffmpeg -i ${1} -af "volumedetect" -f null /dev/null 2>&1 \
        | grep max_volume \
        | cut -d ' ' -f 5
}

function compress_normalize() {
    # Compress and normalize the tracks
    # ${1}: input directory
    # ${2}: volume (archive no.)
    # ${3}: output format, e.g. "ogg"
    mkdir -p ${3}/${2}

    for wav in $(find ${1} -name "*.WAV" | sort); do
        normalized="${3}/${2}/$(basename ${wav} .WAV).${3}"
        if [[ -f ${normalized} ]]; then
            echo "Compress: ${normalized} is already present"
            continue
        fi
        ffmpeg -i ${wav} -af "volume=$(max_volume $wav | tr -d -)dB" ${normalized}
    done
}

dump ${MOUNTPOINT} ${WAV_SUBDIR}
compress_normalize ${WAV_SUBDIR} ${VOLUME} ${FORMAT}