audioinfo

#!/usr/bin/python3
#	jbin - Joe's miscellaneous scripts, tools and configs
#	audioinfo: Analyze audio data
#	Copyright (C) 2022-2022 Johannes Bauer
#
#	This file is part of jbin.
#
#	jbin is free software; you can redistribute it and/or modify
#	it under the terms of the GNU General Public License as published by
#	the Free Software Foundation; this program is ONLY licensed under
#	version 3 of the License, later versions are explicitly excluded.
#
#	jbin is distributed in the hope that it will be useful,
#	but WITHOUT ANY WARRANTY; without even the implied warranty of
#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#	GNU General Public License for more details.
#
#	You should have received a copy of the GNU General Public License
#	along with jbin. If not, see <http://www.gnu.org/licenses/>.
#
#	Johannes Bauer <JohannesBauer@gmx.de>

import sys
import json
import os
import subprocess
import tempfile
from FriendlyArgumentParser import FriendlyArgumentParser

class AudioAnalyzer():
	def __init__(self, args):
		self._args = args

	def _run(self, filename):
		shortname = os.path.basename(filename)
		cmd = [
			"ffmpeg",
			"-hide_banner",
			"-i", filename,
			"-af", "loudnorm=print_format=json",
			"-f", "null",
			"-"
		]
		proc = subprocess.run(cmd, capture_output = True)
		stderr = proc.stderr.decode()
		offset = stderr.find("\n{\n")
		json_data = json.loads(stderr[offset:])
		lufs = float(json_data['input_i'])
		gain = self._args.target_lufs - lufs
		print(f"{shortname}: {lufs:.1f} LUFS, gain {gain:+.1f} dB")

	def run(self):
		for filename in self._args.filename:
			self._run(filename)

parser = FriendlyArgumentParser(description = "Analyze audio data.")
parser.add_argument("-t", "--target-lufs", metavar = "db", type = float, default = -16, help = "Target LUFS. Defaults to %(default).1f dB.")
parser.add_argument("-v", "--verbose", action = "count", default = 0, help = "Increases verbosity. Can be specified multiple times to increase.")
parser.add_argument("filename", nargs = "+", help = "Analyze this audio file")
args = parser.parse_args(sys.argv[1:])

AudioAnalyzer(args).run()