74 lines
2.2 KiB
Python
Executable File
74 lines
2.2 KiB
Python
Executable File
#!/usr/bin/env python3
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import argparse
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import logging
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import shlex
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import subprocess
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HELP = '''
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Normalize audio input.
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The command uses ffprobe to analyze an input file with the ebur128
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filter, and finally run ffmpeg to normalize the input depending on the
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computed adjustment.
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ffmpeg encoding arguments can be passed through the extra arguments
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after options, for example as in:
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normalize.py --input input.mp3 --output output.mp3 -- -loglevel debug -y
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'''
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logging.basicConfig(format='normalize|%(levelname)s> %(message)s', level=logging.INFO)
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log = logging.getLogger()
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class Formatter(
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argparse.ArgumentDefaultsHelpFormatter, argparse.RawDescriptionHelpFormatter
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):
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pass
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def normalize():
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parser = argparse.ArgumentParser(description=HELP, formatter_class=Formatter)
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parser.add_argument('--input', '-i', required=True, help='specify input file')
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parser.add_argument('--output', '-o', required=True, help='specify output file')
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parser.add_argument('--dry-run', '-n', help='simulate commands', action='store_true')
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parser.add_argument('encode_arguments', nargs='*', help='specify encode options used for the actual encoding')
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args = parser.parse_args()
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analysis_cmd = [
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'ffprobe', '-v', 'error', '-of', 'compact=p=0:nk=1',
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'-show_entries', 'frame_tags=lavfi.r128.I', '-f', 'lavfi',
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f"amovie='{args.input}',ebur128=metadata=1"
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]
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def _run_command(cmd, dry_run=False):
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log.info(f"Running command:\n$ {shlex.join(cmd)}")
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if not dry_run:
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result = subprocess.run(cmd, check=True, stdout=subprocess.PIPE)
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return result
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result = _run_command(analysis_cmd)
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loudness = ref = -23
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for line in result.stdout.splitlines():
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sline = line.rstrip()
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if sline:
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loudness = sline
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adjust = ref - float(loudness)
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if abs(adjust) < 0.0001:
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logging.info(f"No normalization needed for '{args.input}'")
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return
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logging.info(f"Adjusting '{args.input}' by {adjust:.2f}dB...")
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normalize_cmd = [
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'ffmpeg', '-i', args.input, '-af', f'volume={adjust:.2f}dB'
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] + args.encode_arguments + [args.output]
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_run_command(normalize_cmd, args.dry_run)
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if __name__ == '__main__':
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normalize()
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