[gst-devel] Using playbin2

Jeffrey Barish jeff_barish at earthlink.net
Mon Jun 15 21:46:06 CEST 2009

Christopher James Halse Rogers wrote:
> I've been learning how to use playbin2 in Banshee and have not seen this
> problem.  It would probably be helpful to post the code in question, to
> see if there's anything obvious to those better versed in playbin2's
> eccentricities.

Most people are probably using the run method of gobject.MainLoop.  I can't
because I have to monitor other events in the gobject loop.  I bet that's
why you haven't seen this problem.  I am posting the code, as you
suggested, in the hope that someone can suggest a simple solution.  I'll be
thinking about whether there is a solution using multithreading.

"""Test of playbin2.  Provide two soundfiles as arguments on the command

import sys, time
import gobject
import gst

class Main:
    def __init__(self):
        self.player = gst.element_factory_make("playbin2", "player")
        self.player.set_property("volume", 0.1)
        bus = self.player.get_bus()
        bus.connect("message", self.on_message)
        self.player.connect('about-to-finish', self.on_about_to_finish)

    def on_message(self, bus, message):
        t = message.type
        if t == gst.MESSAGE_EOS:
        elif t == gst.MESSAGE_ERROR:
            err, debug = message.parse_error()
            print "Error: %s" % err, debug

    def on_about_to_finish(self, playbin):
        self.player.set_property("uri", "file://" + sys.argv[2])

    def start(self):
        filename = sys.argv[1]
        self.player.set_property("uri", "file://" + filename)

        loop = gobject.MainLoop()
        context = loop.get_context()

        # If the loop sleeps longer than 1 us (e.g., 2 us), GStreamer 
        # seg faults. However, such a short sleep results in a CPU load
        # of 100%.  Blocking works, but then it is not possible to monitor
        # other events (not shown, but simulated with the sleep).
        while True:
            while context.pending():
            # Monitor sockets here.
        #may_block = True
        #while True:

player = Main()
Jeffrey Barish

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