opus-embed-cover-art.sh

#!/bin/bash
set -euo pipefail

OPUS_FILE=$1
COVER_ART_WEBP=${OPUS_FILE/.opus/.webp}
[[ -f "$OPUS_FILE" ]]
[[ -f "$COVER_ART_WEBP" ]]

FFMETADATA_TMPFILE=$(mktemp --suffix .cover-art.ffmetadata)
PNG_COVER_TMPFILE=$(mktemp --suffix .cover-art.png)
ffmpeg -i "$COVER_ART_WEBP" "$PNG_COVER_TMPFILE" -y

echo ';FFMETADATA1' > "$FFMETADATA_TMPFILE"
# https://github.com/jovaska1337/misc/blob/master/mkpblock.py
mkpblock.py 3 "" "$PNG_COVER_TMPFILE" >> "$FFMETADATA_TMPFILE"
mkdir -p with-cover-art
ffmpeg -i "$OPUS_FILE" -i "$FFMETADATA_TMPFILE" -map_metadata 1 -c:a copy with-cover-art/"$OPUS_FILE" -y