#!/usr/bin/env bash
set -euo pipefail

find . -type f \( -name "*.opus" -o -name "*.m4a" -o -name "*.mp3" \) -print0 | \
xargs -0 -P "$(nproc)" -I {} sh -c \
  'ffprobe -v quiet -print_format json -show_streams -show_format "$1" 2>/dev/null | jq -r "[.streams[]?.tags.artist, .streams[]?.tags.ARTIST, .format.tags.artist, .format.tags.ARTIST] | map(select(. != null)) | first // empty"' \
  -- {} | \
grep -v '^$' | sort | uniq -c | sort -rn