Tool to convert ADX music files to Ogg files with loop points with FFmpeg

adx2ogg.py

#!/usr/bin/env python3
import argparse, sys, subprocess, pathlib

ffmpeg = "ffmpeg" # Change to ffmpeg path if you need to

parser = argparse.ArgumentParser(description='Convert ADX music to Ogg/Opus files with loop points')

parser.add_argument('input')
parser.add_argument('output', nargs='?')
parser.add_argument('-b', '--bitrate', dest='bitrate', default="64k", help="Set the bitrate (e.g. 64k)")
parser.add_argument('-c', '--codec', dest='codec', default="libopus", help="Set the codec to use. Recommended: libopus, libvorbis, flac")
#parser.add_argument('--mono', dest='mono', action='store_true')

args = parser.parse_args()
if args.output == None:
	output = pathlib.Path(args.input)
	output = output.with_suffix('.ogg')
else:
	output = args.output

f = open(args.input, 'rb')
header = f.read(2)
if (header != b'\x80\x00'):
	sys.exit("Not an ADX file")

f.seek(0x12,0)
fversion = f.read(1)
if (fversion == b'\x03'):
	version = 3
elif (fversion == b'\x04') :
	version = 4
else:
	sys.exit("Only versions 3 and 4 are supported")

f.seek(0x08,0)
samplerate = int.from_bytes(f.read(4), byteorder='big')

if (version == 3):
	f.seek(0x1C,0)
	loopstart = int.from_bytes(f.read(4), byteorder='big')
	f.seek(0x24,0)
	loopend = int.from_bytes(f.read(4), byteorder='big')
elif (version == 4):
	f.seek(0x28,0)
	loopstart = int.from_bytes(f.read(4), byteorder='big')
	f.seek(0x30,0)
	loopend = int.from_bytes(f.read(4), byteorder='big')
	
# Thanks to 
# https://en.wikipedia.org/w/index.php?title=ADX_(file_format)&oldid=1187485353

codec = args.codec

# Opus only supports 48000hz, and loop points are based on
# samples so they get messed up if the sample rate changes
if (codec == "libopus" and samplerate != 48000):
	loopstart = int(loopstart*(48000/samplerate))
	loopend = int(loopend*(48000/samplerate))

command = [ffmpeg, "-i", args.input]

#if args.mono:
#	command.extend(["-ac","1"])

command.extend(["-c:a", codec, "-b:a", args.bitrate, "-metadata", "LOOP_START="+str(loopstart), "-metadata", "LOOP_END="+str(loopend), output])

subprocess.run(command)