mediagoblin/media_types/audio/transcoders.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import pdb
  18 import logging
  19
  20 from mediagoblin.processing import BadMediaFail
  21
  22
  23 _log = logging.getLogger(__name__)
  24
  25 CPU_COUNT = 2 # Just assuming for now
  26
  27 # IMPORT MULTIPROCESSING
  28 try:
  29     import multiprocessing
  30     try:
  31         CPU_COUNT = multiprocessing.cpu_count()
  32     except NotImplementedError:
  33         _log.warning('multiprocessing.cpu_count not implemented!\n'
  34                      'Assuming 2 CPU cores')
  35 except ImportError:
  36     _log.warning('Could not import multiprocessing, assuming 2 CPU cores')
  37
  38 # IMPORT GOBJECT
  39 try:
  40     import gobject
  41     gobject.threads_init()
  42 except ImportError:
  43     raise Exception('gobject could not be found')
  44
  45 # IMPORT PYGST
  46 try:
  47     import pygst
  48
  49     # We won't settle for less. For now, this is an arbitrary limit
  50     # as we have not tested with > 0.10
  51     pygst.require('0.10')
  52
  53     import gst
  54
  55     import gst.extend.discoverer
  56 except ImportError:
  57     raise Exception('gst/pygst >= 0.10 could not be imported')
  58
  59 class AudioTranscoder(object):
  60     def __init__(self):
  61         _log.info('Initializing {0}'.format(self.__class__.__name__))
  62
  63         # Instantiate MainLoop
  64         self._loop = gobject.MainLoop()
  65
  66     def discover(self, src):
  67         _log.info('Discovering {0}'.format(src))
  68         self._discovery_path = src
  69
  70         self._discoverer = gst.extend.discoverer.Discoverer(
  71             self._discovery_path)
  72         self._discoverer.connect('discovered', self.__on_discovered)
  73         self._discoverer.discover()
  74
  75         self._loop.run()  # Run MainLoop
  76
  77         # Once MainLoop has returned, return discovery data
  78         return self._discovery_data
  79
  80     def __on_discovered(self, data, is_media):
  81         if not is_media:
  82             self.halt()
  83             _log.error('Could not discover {0}'.format(self._src_path))
  84             raise BadMediaFail()
  85
  86         _log.debug('Discovered: {0}'.format(data.__dict__))
  87
  88         self._discovery_data = data
  89
  90         # Gracefully shut down MainLoop
  91         self.halt()
  92
  93     def transcode(self, src, dst, **kw):
  94         self._discovery_data = kw.get('data', self.discover(src))
  95
  96         self.__on_progress = kw.get('progress_callback')
  97
  98         quality = kw.get('quality', 0.3)
  99
 100         # Set up pipeline
 101         self.pipeline = gst.parse_launch(
 102             'filesrc location="{src}" ! '
 103             'decodebin2 ! queue ! audiorate tolerance={tolerance} ! '
 104             'audioconvert ! audio/x-raw-float,channels=2 ! '
 105             'vorbisenc quality={quality} ! webmmux ! '
 106             'progressreport silent=true ! '
 107             'filesink location="{dst}"'.format(
 108                 src=src,
 109                 tolerance=80000000,
 110                 quality=quality,
 111                 dst=dst))
 112
 113         self.bus = self.pipeline.get_bus()
 114         self.bus.add_signal_watch()
 115         self.bus.connect('message', self.__on_bus_message)
 116
 117         self.pipeline.set_state(gst.STATE_PLAYING)
 118
 119         self._loop.run()
 120
 121     def __on_bus_message(self, bus, message):
 122         _log.debug(message)
 123
 124         if (message.type == gst.MESSAGE_ELEMENT
 125             and message.structure.get_name() == 'progress'):
 126             data = dict(message.structure)
 127
 128             if self.__on_progress:
 129                 self.__on_progress(data)
 130
 131             _log.info('{0}% done...'.format(
 132                     data.get('percent')))
 133         elif message.type == gst.MESSAGE_EOS:
 134             _log.info('Done')
 135             self.halt()
 136
 137     def halt(self):
 138         _log.info('Quitting MainLoop gracefully...')
 139         gobject.idle_add(self._loop.quit)
 140
 141 if __name__ == '__main__':
 142     import sys
 143     logging.basicConfig()
 144     _log.setLevel(logging.INFO)
 145
 146     transcoder = AudioTranscoder()
 147     data = transcoder.discover(sys.argv[1])
 148     res = transcoder.transcode(*sys.argv[1:3])
 149
 150     pdb.set_trace()