Audio autoplugin example using 'uridecodebin' element

uridecodebin.py

#!/usr/bin/env python

# uridecodebin.py - Audio autoplugin example using 'uridecodebin' element
#
# Based on:
# decodebin.py - Audio autopluging example using 'decodebin' element
# Copyright (C) 2006 Jason Gerard DeRose <jderose@jasonderose.org>

# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.

import sys

import gobject
gobject.threads_init()

import pygst
pygst.require('0.10')
import gst


class Uridecodebin:
    def __init__(self, location):
        # The pipeline
        self.pipeline = gst.Pipeline()

        # Create bus and connect several handlers
        self.bus = self.pipeline.get_bus()
        self.bus.add_signal_watch()
        self.bus.connect('message::eos', self.on_eos)
        self.bus.connect('message::tag', self.on_tag)
        self.bus.connect('message::error', self.on_error)

        # Create elements
        self.srcdec = gst.element_factory_make('uridecodebin')
        self.conv = gst.element_factory_make('audioconvert')
        self.rsmpl = gst.element_factory_make('audioresample')
        self.sink = gst.element_factory_make('alsasink')

        # Set 'uri' property on uridecodebin
        self.srcdec.set_property('uri', location)

        # Connect handler for 'pad-added' signal
        self.srcdec.connect('pad-added', self.on_pad_added)

        # Add elements to pipeline
        self.pipeline.add(self.srcdec, self.conv, self.rsmpl, self.sink)

        # Link *some* elements
        # This is completed in self.on_new_decoded_pad()
        gst.element_link_many(self.conv, self.rsmpl, self.sink)

        # Reference used in self.on_new_decoded_pad()
        self.apad = self.conv.get_pad('sink')

        # The MainLoop
        self.mainloop = gobject.MainLoop()

        # And off we go!
        self.pipeline.set_state(gst.STATE_PLAYING)
        self.mainloop.run()

    def on_pad_added(self, element, pad):
        caps = pad.get_caps()
        name = caps[0].get_name()
        print 'on_pad_added:', name
        if name == 'audio/x-raw-float' or name == 'audio/x-raw-int':
            if not self.apad.is_linked(): # Only link once
                pad.link(self.apad)

    def on_eos(self, bus, msg):
        print 'on_eos'
        self.pipeline.set_state(gst.STATE_NULL)
        self.mainloop.quit()

    def on_tag(self, bus, msg):
        taglist = msg.parse_tag()
        print 'on_tag:'
        for key in taglist.keys():
            print '\t%s = %s' % (key, taglist[key])

    def on_error(self, bus, msg):
        error = msg.parse_error()
        print 'on_error:', error[1]
        self.mainloop.quit()

if __name__ == '__main__':
    if len(sys.argv) == 2:
        Uridecodebin(sys.argv[1])
    else:
        print 'Usage: %s file:///path/to/media/file' % sys.argv[0]