47 lines
1.7 KiB
Python
47 lines
1.7 KiB
Python
import logging
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import re
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import subprocess
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from .analyzer import Analyzer
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class ReplayGainAnalyzer(Analyzer):
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"""This class extracts the ReplayGain using a tool from the python-rgain package."""
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REPLAYGAIN_EXECUTABLE = "replaygain" # From the rgain3 python package
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@staticmethod
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def analyze(filename, metadata):
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"""Extracts the Replaygain loudness normalization factor of a track.
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:param filename: The full path to the file to analyzer
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:param metadata: A metadata dictionary where the results will be put
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:return: The metadata dictionary
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"""
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""" The -d flag means do a dry-run, ie. don't modify the file directly.
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"""
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command = [ReplayGainAnalyzer.REPLAYGAIN_EXECUTABLE, "-d", filename]
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try:
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results = subprocess.check_output(
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command,
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stderr=subprocess.STDOUT,
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close_fds=True,
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universal_newlines=True,
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)
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gain_match = (
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r"Calculating Replay Gain information \.\.\.(?:\n|.)*?:([\d.-]*) dB"
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)
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replaygain = re.search(gain_match, results).group(1)
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metadata["replay_gain"] = float(replaygain)
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except OSError as e: # replaygain was not found
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logging.warning(
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"Failed to run: %s - %s. %s"
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% (command[0], e.strerror, "Do you have python-rgain installed?")
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)
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except subprocess.CalledProcessError as e: # replaygain returned an error code
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logging.warning("%s %s %s", e.cmd, e.output, e.returncode)
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except Exception as e:
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logging.warning(e)
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return metadata
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