subprojects/gst-python/old_examples/decodebin.py

   1 #!/usr/bin/env python
   2
   3 # decodebin.py - Audio autopluging example using 'decodebin' element
   4 # Copyright (C) 2006 Jason Gerard DeRose <jderose@jasonderose.org>
   5
   6 # This library is free software; you can redistribute it and/or
   7 # modify it under the terms of the GNU Library General Public
   8 # License as published by the Free Software Foundation; either
   9 # version 2 of the License, or (at your option) any later version.
  10 #
  11 # This library is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 # Library General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU Library General Public
  17 # License along with this library; if not, write to the
  18 # Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19 # Boston, MA 02110-1301, USA.
  20
  21 import sys
  22
  23 import gobject
  24 gobject.threads_init()
  25
  26 import pygst
  27 pygst.require('0.10')
  28 import gst
  29
  30
  31 class Decodebin:
  32         def __init__(self, location):
  33                 # The pipeline
  34                 self.pipeline = gst.Pipeline()
  35
  36                 # Create bus and connect several handlers
  37                 self.bus = self.pipeline.get_bus()
  38                 self.bus.add_signal_watch()
  39                 self.bus.connect('message::eos', self.on_eos)
  40                 self.bus.connect('message::tag', self.on_tag)
  41                 self.bus.connect('message::error', self.on_error)
  42
  43                 # Create elements
  44                 self.src = gst.element_factory_make('filesrc')
  45                 self.dec = gst.element_factory_make('decodebin')
  46                 self.conv = gst.element_factory_make('audioconvert')
  47                 self.rsmpl = gst.element_factory_make('audioresample')
  48                 self.sink = gst.element_factory_make('alsasink')
  49
  50                 # Set 'location' property on filesrc
  51                 self.src.set_property('location', location)
  52
  53                 # Connect handler for 'new-decoded-pad' signal
  54                 self.dec.connect('new-decoded-pad', self.on_new_decoded_pad)
  55
  56                 # Add elements to pipeline
  57                 self.pipeline.add(self.src, self.dec, self.conv, self.rsmpl, self.sink)
  58
  59                 # Link *some* elements
  60                 # This is completed in self.on_new_decoded_pad()
  61                 self.src.link(self.dec)
  62                 gst.element_link_many(self.conv, self.rsmpl, self.sink)
  63
  64                 # Reference used in self.on_new_decoded_pad()
  65                 self.apad = self.conv.get_pad('sink')
  66
  67                 # The MainLoop
  68                 self.mainloop = gobject.MainLoop()
  69
  70                 # And off we go!
  71                 self.pipeline.set_state(gst.STATE_PLAYING)
  72                 self.mainloop.run()
  73
  74
  75         def on_new_decoded_pad(self, element, pad, last):
  76                 caps = pad.get_caps()
  77                 name = caps[0].get_name()
  78                 print 'on_new_decoded_pad:', name
  79                 if name == 'audio/x-raw-float' or name == 'audio/x-raw-int':
  80                         if not self.apad.is_linked(): # Only link once
  81                                 pad.link(self.apad)
  82
  83
  84         def on_eos(self, bus, msg):
  85                 print 'on_eos'
  86                 self.mainloop.quit()
  87
  88
  89         def on_tag(self, bus, msg):
  90                 taglist = msg.parse_tag()
  91                 print 'on_tag:'
  92                 for key in taglist.keys():
  93                         print '\t%s = %s' % (key, taglist[key])
  94
  95
  96         def on_error(self, bus, msg):
  97                 error = msg.parse_error()
  98                 print 'on_error:', error[1]
  99                 self.mainloop.quit()
 100
 101
 102
 103
 104
 105 if __name__ == '__main__':
 106         if len(sys.argv) == 2:
 107                 Decodebin(sys.argv[1])
 108         else:
 109                 print 'Usage: %s /path/to/media/file' % sys.argv[0]