GStreamer Python Custom Message

custom_message.py

import gi
gi.require_version('Gst', '1.0')
from gi.repository import GObject, Gst
from threading import Thread, Event

Gst.init(None)

class Main:
    def __init__(self):
        self.pipeline = Gst.Pipeline.new("pipeline")
        self.bus = self.pipeline.get_bus()

        self.videotestsrc = Gst.ElementFactory.make("videotestsrc", "videotestsrc")
        self.pipeline.add(self.videotestsrc)

        self.autovideosink = Gst.ElementFactory.make("autovideosink", "autovideosink")
        self.pipeline.add(self.autovideosink)

        self.videotestsrc.link(self.autovideosink)

    def send_custom_message(self):
        while not self.stop_event.is_set():
            self.stop_event.wait(1)

            if self.stop_event.is_set():
                break

            custom_structure = Gst.Structure.new_empty("custom_message")
            custom_message = Gst.Message.new_application(None, custom_structure)
            self.bus.post(custom_message)

    def run(self):
        self.pipeline.set_state(Gst.State.PLAYING)

        self.stop_event = Event()
        self.change_source_thread = Thread(target=self.send_custom_message)
        self.change_source_thread.start()

        while True:
            try:
                message = self.bus.timed_pop(Gst.SECOND)

                if message == None:
                    pass
                elif message.type == Gst.MessageType.APPLICATION:
                    print(message.get_structure().get_name())
                elif message.type == Gst.MessageType.EOS:
                    break
                elif message.type == Gst.MessageType.ERROR:
                    break
            except KeyboardInterrupt:
                break

        self.stop_event.set()
        self.pipeline.set_state(Gst.State.NULL)

start = Main()
start.run()