beets/beetsplug/replaygain.py
2012-10-15 14:31:31 -07:00

228 lines
8.9 KiB
Python
Executable file

#Copyright (c) 2012, Fabrice Laporte
#
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:
#
#The above copyright notice and this permission notice shall be included in
#all copies or substantial portions of the Software.
#
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
#THE SOFTWARE.
import logging
import subprocess
import os
from beets import ui
from beets.plugins import BeetsPlugin
from beets.mediafile import MediaFile, FileTypeError, UnreadableFileError
from beets.util import syspath
log = logging.getLogger('beets')
DEFAULT_REFERENCE_LOUDNESS = 89
class ReplayGainError(Exception):
"""Raised when an error occurs during mp3gain/aacgain execution.
"""
def call(args):
"""Execute the command indicated by `args` (an array of strings) and
return the command's output. The stderr stream is ignored. If the command
exits abnormally, a ReplayGainError is raised.
"""
try:
with open(os.devnull, 'w') as devnull:
return subprocess.check_output(args, stderr=devnull)
except subprocess.CalledProcessError as e:
raise ReplayGainError(
"{0} exited with status {1}".format(args[0], e.returncode)
)
class ReplayGainPlugin(BeetsPlugin):
"""Provides ReplayGain analysis.
"""
def __init__(self):
self.register_listener('album_imported', self.album_imported)
self.register_listener('item_imported', self.item_imported)
def configure(self, config):
self.overwrite = ui.config_val(config,'replaygain',
'overwrite', False, bool)
self.noclip = ui.config_val(config,'replaygain',
'noclip', True, bool)
self.apply_gain = ui.config_val(config,'replaygain',
'apply_gain', False, bool)
self.albumgain = ui.config_val(config,'replaygain',
'albumgain', False, bool)
target_level = float(ui.config_val(config,'replaygain',
'targetlevel', DEFAULT_REFERENCE_LOUDNESS))
self.gain_offset = int(target_level - DEFAULT_REFERENCE_LOUDNESS)
self.command = ui.config_val(config,'replaygain','command', None)
if self.command:
# Explicit executable path.
if not os.path.isfile(self.command):
raise ui.UserError(
'replaygain command does not exist: {0}'.format(
self.command
)
)
else:
# Check whether the program is in $PATH.
for cmd in ('mp3gain', 'aacgain'):
try:
call([cmd, '-v'])
self.command = cmd
except OSError as exc:
pass
if not self.command:
raise ui.UserError(
'no replaygain command found: install mp3gain or aacgain'
)
def album_imported(self, lib, album, config):
try:
media_files = \
[MediaFile(syspath(item.path)) for item in album.items()]
self.write_rgain(media_files, self.compute_rgain(media_files))
except (FileTypeError, UnreadableFileError,
TypeError, ValueError) as e:
log.error("failed to calculate replaygain: %s ", e)
def item_imported(self, lib, item, config):
try:
mf = MediaFile(syspath(item.path))
self.write_rgain([mf], self.compute_rgain([mf]))
except (FileTypeError, UnreadableFileError,
TypeError, ValueError) as e:
log.error("failed to calculate replaygain: %s ", e)
def requires_gain(self, mf):
'''Does the gain need to be computed?'''
return self.overwrite or \
(not mf.rg_track_gain or not mf.rg_track_peak) or \
((not mf.rg_album_gain or not mf.rg_album_peak) and \
self.albumgain)
def get_recommended_gains(self, media_paths):
'''Returns recommended track and album gain values'''
rgain_out = call([self.command, '-o', '-d', str(self.gain_offset)] +
media_paths)
rgain_out = rgain_out.strip('\n').split('\n')
keys = rgain_out[0].split('\t')[1:]
tracks_mp3_gain = [dict(zip(keys,
[float(x) for x in l.split('\t')[1:]]))
for l in rgain_out[1:-1]]
album_mp3_gain = int(rgain_out[-1].split('\t')[1])
return [tracks_mp3_gain, album_mp3_gain]
def parse_tool_output(self, text):
"""Given the tab-delimited output from an invocation of mp3gain
or aacgain, parse the text and return a list of dictionaries
containing information about each analyzed file.
"""
out = []
for line in text.split('\n'):
parts = line.split('\t')
if len(parts) != 6 or parts[0] == 'File':
continue
out.append({
'file': parts[0],
'mp3gain': int(parts[1]),
'gain': float(parts[2]),
'peak': float(parts[3]),
'maxgain': int(parts[4]),
'mingain': int(parts[5]),
})
return out
def reduce_gain_for_noclip(self, track_gains, albumgain):
'''Reduce albumgain value until no song is clipped.
No command switch give you the max no-clip in album mode.
So we consider the recommended gain and decrease it until no song is
clipped when applying the gain.
Formula found at:
http://www.hydrogenaudio.org/forums/lofiversion/index.php/t10630.html
'''
if albumgain > 0:
maxpcm = max([t['Max Amplitude'] for t in track_gains])
while (maxpcm * (2**(albumgain/4.0)) > 32767):
albumgain -= 1
return albumgain
def compute_rgain(self, media_files):
"""Compute ReplayGain values and return a list of results
dictionaries as given by `parse_tool_output`.
"""
media_files = [mf for mf in media_files if self.requires_gain(mf)]
if not media_files:
log.debug('replaygain: no gain to compute')
return
media_paths = [syspath(mf.path) for mf in media_files]
if self.albumgain:
track_gains, album_gain = self.get_recommended_gains(media_paths)
if self.noclip:
self.gain_offset = self.reduce_gain_for_noclip(track_gains,
album_gain)
# Construct shell command. The "-o" option makes the output
# easily parseable (tab-delimited). "-s s" forces gain
# recalculation even if tags are already present and disables
# tag-writing; this turns the mp3gain/aacgain tool into a gain
# calculator rather than a tag manipulator because we take care
# of changing tags ourselves.
cmd = [self.command, '-o', '-s', 's']
if self.noclip:
# Adjust to avoid clipping.
cmd = cmd + ['-k']
else:
# Disable clipping warning.
cmd = cmd + ['-c']
if self.apply_gain:
# Lossless audio adjustment.
cmd = cmd + ['-r']
cmd = cmd + ['-d', str(self.gain_offset)]
cmd = cmd + media_paths
log.debug('replaygain: analyzing {0} files'.format(len(media_files)))
output = call(cmd)
log.debug('replaygain: analysis finished')
return self.parse_tool_output(output)
def write_rgain(self, media_files, rgain_infos):
"""Write computed gain values for each media file.
"""
for mf, info in zip(media_files, rgain_infos):
try:
mf.rg_track_gain = float(info['gain'])
mf.rg_track_peak = float(info['peak'])
log.debug('replaygain: wrote track gain {0}, peak {1}'.format(
mf.rg_track_gain, mf.rg_track_peak
))
mf.save()
except (UnreadableFileError, TypeError, ValueError):
log.error("replaygain: write failed for %s" % (mf.title))