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ReplayGain analysis in airtime_analyzer using python-rgain

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* Implemented Replaygain analysis for Ogg Vorbis, MP3, MP4, and FLAC
  using python-rgain
* Added unit tests for ReplayGainAnalyzer
* Squashed stderr output in ReplayGainAnalyzer and CuePointAnalyzer
* Clean up
This commit is contained in:
Albert Santoni 2014-12-11 14:12:41 -05:00
parent 38bd45b8dc
commit 4dd2768755
7 changed files with 89 additions and 36 deletions
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33
python_apps/airtime_analyzer/airtime_analyzer/replaygain_analyzer.py
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@ -1,14 +1,12 @@
import subprocess
import logging
from analyzer import Analyzer
class ReplayGainAnalyzer(Analyzer):
''' This class extracts the cue-in time, cue-out time, and length of a track using silan. '''
''' This class extracts the ReplayGain using a tool from the python-rgain package. '''
BG1770GAIN_EXECUTABLE = 'bg1770gain'
def __init__(self):
pass
REPLAYGAIN_EXECUTABLE = 'replaygain' # From the python-rgain package
@staticmethod
def analyze(filename, metadata):
@ -17,23 +15,20 @@ class ReplayGainAnalyzer(Analyzer):
:param metadata: A metadata dictionary where the results will be put
:return: The metadata dictionary
'''
''' The -d 00:01:00 flag means it will let the decoding run for a maximum of 1 minute. This is a safeguard
in case the libavcodec decoder gets stuck in an infinite loop.
''' The -d flag means do a dry-run, ie. don't modify the file directly.
'''
command = [ReplayGainAnalyzer.BG1770GAIN_EXECUTABLE, '--replaygain', '-d', '00:01:00', '-f', 'JSON', filename]
command = [ReplayGainAnalyzer.REPLAYGAIN_EXECUTABLE, '-d', filename]
try:
results_json = subprocess.check_output(command)
silan_results = json.loads(results_json)
metadata['length_seconds'] = float(silan_results['file duration'])
# Conver the length into a formatted time string
track_length = datetime.timedelta(seconds=metadata['length_seconds'])
metadata["length"] = str(track_length)
metadata['cuein'] = silan_results['sound'][0][0]
metadata['cueout'] = silan_results['sound'][0][1]
results = subprocess.check_output(command, stderr=subprocess.STDOUT)
filename_token = "%s: " % filename
rg_pos = results.find(filename_token, results.find("Calculating Replay Gain information")) + len(filename_token)
db_pos = results.find(" dB", rg_pos)
replaygain = results[rg_pos:db_pos]
metadata['replaygain'] = float(replaygain)
except OSError as e: # silan was not found
logging.warn("Failed to run: %s - %s. %s" % (command[0], e.strerror, "Do you have silan installed?"))
except subprocess.CalledProcessError as e: # silan returned an error code
except OSError as e: # replaygain was not found
logging.warn("Failed to run: %s - %s. %s" % (command[0], e.strerror, "Do you have python-rgain installed?"))
except subprocess.CalledProcessError as e: # replaygain returned an error code
logging.warn("%s %s %s", e.cmd, e.message, e.returncode)
except Exception as e:
logging.warn(e)