[gst-devel] Several novice questions

Jeffrey Barish jeff_barish at earthlink.net
Mon Jan 21 08:12:07 CET 2008

Edward Hervey wrote:

> On Fri, 2008-01-18 at 08:28 -0700, Jeffrey Barish wrote:
>> 1. I gather that I am expected to change the state of the player on EOS
>> (which seems strange to me as I would have thought that the player would
>> know to stop playing when the stream has ended).  To this end, I included
>> the following code:
>> self.player = gst.element_factory_make('playbin', 'player')
>> bus = self.player.get_bus()
>> bus.add_signal_watch()
>> bus.connect('message', self.on_message)
>> def on_message(self, bus, message):
>> t = message.type
>> if t in (gst.MESSAGE_EOS, gst.MESSAGE_ERROR):
>>     self.player.set_state(gst.STATE_NULL)
>> However, on_message is never called.  Any idea what I am doing wrong?
> Are you running a mainloop ? I think it won't work if you're not
> runnign a mainloop.

It turns out that you were exactly right.  The chunk of code in which
GStreamer is running is outside the GTK main loop.  When I put the code in
a gobject mainloop, I do receive messages.  Thank you for the suggestion.

I am still wondering why query_position(gst.FORMAT_PERCENT) produces a query
error whereas query_position(gst.FORMAT_TIME) does not and whether
gst.FORMAT_PERCENT is a misnomer.
Jeffrey Barish

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