46 lines
2.1 KiB
Python
46 lines
2.1 KiB
Python
import subprocess
|
|
import logging
|
|
import traceback
|
|
import json
|
|
import datetime
|
|
from analyzer import Analyzer
|
|
|
|
|
|
class CuePointAnalyzer(Analyzer):
|
|
''' This class extracts the cue-in time, cue-out time, and length of a track using silan. '''
|
|
|
|
SILAN_EXECUTABLE = 'silan'
|
|
|
|
@staticmethod
|
|
def analyze(filename, metadata):
|
|
''' Extracts the cue-in and cue-out times along and sets the file duration based on that.
|
|
The cue points are there to skip the silence at the start and end of a track, and are determined
|
|
using "silan", which analyzes the loudness in a track.
|
|
:param filename: The full path to the file to analyzer
|
|
:param metadata: A metadata dictionary where the results will be put
|
|
:return: The metadata dictionary
|
|
'''
|
|
''' The silan -F 0.99 parameter tweaks the highpass filter. The default is 0.98, but at that setting,
|
|
the unit test on the short m4a file fails. With the new setting, it gets the correct cue-in time and
|
|
all the unit tests pass.
|
|
'''
|
|
command = [CuePointAnalyzer.SILAN_EXECUTABLE, '-b', '-F', '0.99', '-f', 'JSON', '-t', '1.0', filename]
|
|
try:
|
|
results_json = subprocess.check_output(command, stderr=subprocess.STDOUT, close_fds=True)
|
|
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'] = format(silan_results['sound'][0][0], 'f')
|
|
metadata['cueout'] = format(silan_results['sound'][0][1], 'f')
|
|
|
|
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
|
|
logging.warn("%s %s %s", e.cmd, e.message, e.returncode)
|
|
except Exception as e:
|
|
logging.warn(e)
|
|
|
|
return metadata
|