example on how to change videomixer property in sync with the mixer thread

1 files changed, 61 insertions, 0 deletions

diff --git a/voctocore/experiments/sync-videomix.py b/voctocore/experiments/sync-videomix.py
new file mode 100755
index 0000000..0f6e780
--- /dev/null
+++ b/voctocore/experiments/sync-videomix.py
@@ -0,0 +1,61 @@
+#!/usr/bin/python3
+import gi, time
+import socket
+
+# import GStreamer and GTK-Helper classes
+gi.require_version('Gst', '1.0')
+from gi.repository import GLib, Gst, GObject
+
+# init GObject before importing local classes
+GObject.threads_init()
+Gst.init(None)
+
+class Example:
+	def __init__(self):
+		self.mainloop = GObject.MainLoop()
+
+		pipeline = """
+			videotestsrc pattern=red !
+			{caps} !
+			identity sync=true signal-handoffs=false !
+			mix.
+
+			videotestsrc pattern=green !
+			{caps} !
+			identity sync=true signal-handoffs=false !
+			mix.
+
+			videomixer name=mix !
+			{caps} !
+			identity name=sig !
+			videoconvert !
+			pngenc !
+			multifilesink location=frame%04d.png
+		""".format(
+			caps='video/x-raw,height=450,width=800,format=I420,framerate=25/1'
+		)
+
+		self.pipeline = Gst.parse_launch(pipeline)
+		sig = self.pipeline.get_by_name('sig')
+		sig.connect('handoff', self.handoff)
+
+		self.mix = self.pipeline.get_by_name('mix')
+		self.state = 0
+
+	def handoff(self, object, buffer):
+		mixerpad = self.mix.get_static_pad('sink_1')
+
+		print('handoff, alpha=%u' % self.state)
+		mixerpad.set_property('alpha', self.state)
+		self.state = 0 if self.state else 1
+
+	def run(self):
+		self.pipeline.set_state(Gst.State.PLAYING)
+		self.mainloop.run()
+
+	def kill(self):
+		self.pipeline.set_state(Gst.State.NULL)
+		self.mainloop.quit()
+
+example = Example()
+example.run()