#!/usr/bin/env pythonimport sysimport pygstpygst.require('0.10')import gstimport gobjectgobject.threads_init()# 1 create a pipeline# 2 set it to playing# 3 wait for pipeline to go to playing# 4 get the pipeline clock and the base_time# 5 create a NetTimeProvider using the clock and port# 6 inform clients of port and base_timeclass MasterPipeline: def __init__(self, uri, port): self.port = int(port) self.uri = uri # 1 create a pipeline self.pipeline = gst.element_factory_make("playbin") self.pipeline.set_property("uri", 'file://' + self.uri) # connect a method to the bus messages self.bus = self.pipeline.get_bus() self.bus.add_signal_watch() self.bus.connect('message', self._busMessageCb) # create a mainloop to do event-based programming self.mainloop = gobject.MainLoop() def run(self): # 2 set pipeline to playing if self.pipeline.set_state(gst.STATE_PLAYING) == gst.STATE_CHANGE_FAILURE: print "Couldn't set the pipeline to PLAYING" self.mainloop.run() def _busMessageCb(self, bus, message): if message.type == gst.MESSAGE_STATE_CHANGED: if message.src == self.pipeline: previous, current, pending = message.parse_state_changed() if previous == gst.STATE_PAUSED and current == gst.STATE_PLAYING and pending == gst.STATE_VOID_PENDING: # The pipeline is now playing # get the clock clock = self.pipeline.get_clock() # get the base_time base_time = self.pipeline.get_base_time() # Create the NetTimeProvider provider = gst.NetTimeProvider(clock, None, self.port) # inform clients of port and base_time print ("Start slave as: python ./play-slave.py %s [IP] %d %d" % (self.uri, self.port, base_time)) elif message.type in [gst.MESSAGE_ERROR, gst.MESSAGE_EOS]: # if we have finished playing or there is an error, we exit the mainloop self.mainloop.quit()if __name__ == '__main__': uri, port = sys.argv[1:] pipeline = MasterPipeline(uri, port) pipeline.run()