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 GObject
  11 GObject.threads_init()
  12
  13
  14 # The following pipeline works
  15 PIPELINE = """
  16 videotestsrc pattern=0 ! selector.
  17 videotestsrc pattern=13 ! selector.
  18 input-selector name=selector ! autovideosink
  19 """
  20
  21
  22 class Player:
  23     def __init__(self):
  24         self.loop = GObject.MainLoop()
  25         self.pipeline = Gst.parse_launch(PIPELINE)
  26         self.selector = self.pipeline.get_by_name('selector')
  27
  28         pad = self.selector.get_static_pad("sink_0")
  29         self.selector.set_property("active-pad", pad)
  30         print("n-pads: %d" % self.selector.get_property("n-pads"))
  31
  32         bus = self.pipeline.get_bus()
  33         bus.add_signal_watch()
  34         bus.connect('message::eos', self.on_eos)
  35         bus.connect('message::error', self.on_error)
  36         bus.connect('message::state-changed', self.on_state_changed)
  37
  38     def run(self):
  39         self.pipeline.set_state(Gst.State.PLAYING)
  40         self.loop.run()
  41
  42     def quit(self):
  43         self.pipeline.set_state(Gst.State.NULL)
  44         self.loop.quit()
  45
  46     def switch(self):
  47         active_pad = self.selector.get_property("active-pad")
  48         if active_pad.get_name() == "sink_0":
  49             new_pad = self.selector.get_static_pad("sink_1")
  50         else:
  51             new_pad = self.selector.get_static_pad("sink_0")
  52
  53         print("switching from %s to %s" % (active_pad.get_name(),
  54                                            new_pad.get_name()))
  55
  56         self.selector.set_property("active-pad", new_pad)
  57
  58     def on_eos(self, bus, msg):
  59         self.quit()
  60
  61     def on_error(self, bus, msg):
  62         (err, debug) = msg.parse_error()
  63         print("Error: %s" % err)
  64         self.quit()
  65
  66     def on_state_changed(self, bus, msg):
  67         if msg.src != self.pipeline:
  68             return
  69
  70         old_state, new_state, pending = msg.parse_state_changed()
  71         print("%s from %s to %s" % (msg.src.get_name(), old_state, new_state))
  72
  73
  74 def main():
  75     player = Player()
  76
  77     def stdin_cb(source, condition):
  78         source.readline()
  79         player.switch()
  80         return True
  81
  82     GObject.io_add_watch(sys.stdin, GObject.IO_IN, stdin_cb)
  83
  84     print("\nPress Enter to switch the source\n")
  85     player.run()
  86
  87
  88 if __name__ == '__main__':
  89     sys.exit(main())