python/gst-input-selector-switch.py

   1 #!/usr/bin/env python3
   2
   3 import sys
   4
   5 import gi
   6 gi.require_version('Gst', '1.0')
   7 from gi.repository import Gst
   8 Gst.init(None)
   9
  10 from gi.repository import GLib
  11
  12
  13 # The following pipeline works
  14 PIPELINE = """
  15 videotestsrc pattern=0 ! selector.
  16 videotestsrc pattern=18 background-color=4294901760 ! selector.
  17 input-selector name=selector ! autovideosink
  18 """
  19
  20
  21 class Player:
  22     def __init__(self):
  23         self.loop = GLib.MainLoop()
  24         self.pipeline = Gst.parse_launch(PIPELINE)
  25         self.selector = self.pipeline.get_by_name('selector')
  26
  27         pad = self.selector.get_static_pad("sink_0")
  28         self.selector.set_property("active-pad", pad)
  29         print("n-pads: %d" % self.selector.get_property("n-pads"))
  30
  31         bus = self.pipeline.get_bus()
  32         bus.add_signal_watch()
  33         bus.connect('message::eos', self.on_eos)
  34         bus.connect('message::error', self.on_error)
  35         bus.connect('message::state-changed', self.on_state_changed)
  36
  37     def run(self):
  38         self.pipeline.set_state(Gst.State.PLAYING)
  39         self.loop.run()
  40
  41     def quit(self):
  42         self.pipeline.set_state(Gst.State.NULL)
  43         self.loop.quit()
  44
  45     def on_switch(self):
  46         active_pad = self.selector.get_property("active-pad")
  47         if active_pad.get_name() == "sink_0":
  48             new_pad = self.selector.get_static_pad("sink_1")
  49         else:
  50             new_pad = self.selector.get_static_pad("sink_0")
  51
  52         print("switching from %s to %s" % (active_pad.get_name(),
  53                                            new_pad.get_name()))
  54
  55         self.selector.set_property("active-pad", new_pad)
  56
  57     def on_eos(self, bus, msg):
  58         self.quit()
  59
  60     def on_error(self, bus, msg):
  61         (err, debug) = msg.parse_error()
  62         print("Error: %s" % err)
  63         self.quit()
  64
  65     def on_state_changed(self, bus, msg):
  66         if msg.src != self.pipeline:
  67             return
  68
  69         old_state, new_state, pending = msg.parse_state_changed()
  70         print("%s from %s to %s" % (msg.src.get_name(), old_state, new_state))
  71
  72
  73 def main():
  74     player = Player()
  75
  76     def stdin_cb(source, condition):
  77         source.readline()
  78         player.on_switch()
  79         return True
  80
  81     GLib.io_add_watch(sys.stdin, GLib.IO_IN, stdin_cb)
  82
  83     print("\nPress Enter to switch the source\n")
  84     player.run()
  85
  86
  87 if __name__ == '__main__':
  88     sys.exit(main())