#!/usr/bin/env python3
# Copy ReplayGain tags from various formats to MP3 (for iPod downconversion;
# ffmpeg does not copy RVA2 automatically)
import argparse
import mutagen
import sys
from nullroute.mp3tags import GainValue

parser = argparse.ArgumentParser()
parser.add_argument("src_file")
parser.add_argument("dst_file")
args = parser.parse_args()

srctag = mutagen.File(args.src_file)
dsttag = mutagen.mp3.MP3(args.dst_file)

gv = GainValue.import_tag(srctag, 'track')
if not gv:
    print("No ReplayGain tag found in %r" % args.src_file, file=sys.stderr)
    print(srctag)
    exit(1)

gv.export_id3(dsttag)
dsttag.save()
