Of course you can combine example 2 and 3 and get audio AND video

diff --git a/example2+3.py b/example2+3.py
new file mode 100755 (executable)
index 0000000..d203020
--- /dev/null
+++ b/example2+3.py
@@ -0,0 +1,100 @@
+#!/usr/bin/env python
+# Let's see if we can get a viewport AND audio working, combining ex. 2 and 3
+
+# GdkX11 to get access to xid, GstVideo to get access to set_window_handle
+from gi.repository import Gtk, Gst, GdkX11, GstVideo
+import signal
+
+class Main:
+    def __init__(self):
+        
+        # Create gui bits and bobs
+
+        self.mainwindow = Gtk.Builder()
+        self.mainwindow.add_from_file("example3.glade")
+        
+        signals = {
+            "on_play_clicked" : self.OnPlay,
+            "on_stop_clicked" : self.OnStop,
+            "on_quit_clicked" : self.OnQuit,
+        }
+
+        self.mainwindow.connect_signals(signals)
+
+        # Create GStreamer bits and bobs
+
+        # Initiate the pipeline
+        Gst.init(None)
+        self.pipeline = Gst.Pipeline("mypipeline")
+
+        # Add a videotestsrc element to the pipeline, set it to pattern "snow."
+        self.videotestsrc = Gst.ElementFactory.make("videotestsrc", "videosource")
+        self.videotestsrc.set_property("pattern", "snow")
+        self.pipeline.add(self.videotestsrc)
+        
+        # Add a capsfilter that we want to apply to our videotestsrc
+        self.videotestcaps = Gst.ElementFactory.make("capsfilter", "videotestcaps")
+        self.videotestcaps.set_property("caps",Gst.Caps.from_string("video/x-raw,width=640,height=480"))
+        self.pipeline.add(self.videotestcaps)
+        
+        # Link the capsfilter to the videotestsrc
+        self.videotestsrc.link(self.videotestcaps)
+
+        # Add a videosink element to the pipeline
+        self.videosink = Gst.ElementFactory.make("autovideosink", "videosink")
+        self.pipeline.add(self.videosink)
+
+        # Link the already linked videotestcaps to the sink
+        self.videotestcaps.link(self.videosink)
+
+        # Add an audiotestsrc element to the pipeline
+        self.audiotestsrc = Gst.ElementFactory.make("audiotestsrc", "audio")
+        self.audiotestsrc.set_property("freq", 800)
+        self.pipeline.add(self.audiotestsrc)
+
+        # Add a pulsesink element to the pipeline
+        self.pulsesink = Gst.ElementFactory.make("pulsesink", "sink")
+        self.pipeline.add(self.pulsesink)
+
+        # Link the two elements together
+        self.audiotestsrc.link(self.pulsesink)
+        
+        # Set up a bus to our pipeline to get notified when the video is ready
+        self.bus = self.pipeline.get_bus()
+        self.bus.enable_sync_message_emission()
+        self.bus.connect("sync-message::element", self.OnSyncElement)
+        
+        # Summon the window and connect the window's close button to quit
+        self.window = self.mainwindow.get_object("mainwindow")
+        self.window.connect("delete-event", Gtk.main_quit)
+        self.window.show_all()
+        
+        # Get window ID of the viewport widget from the GUI
+        self.win_id = self.mainwindow.get_object("viewport").get_window().get_xid()
+
+
+    # When we get a message that video is ready to display, set the 
+    # correct window id to hook it to our viewport
+    def OnSyncElement(self, bus, message):
+        if message.get_structure().get_name() == "prepare-window-handle":
+            print "prepare-window-handle"
+            message.src.set_window_handle(self.win_id)
+
+    def OnPlay(self, widget):
+        print "play"
+        self.pipeline.set_state(Gst.State.PLAYING)
+
+    def OnStop(self, widget):
+        print "stop"
+        self.pipeline.set_state(Gst.State.READY)
+        
+    def OnQuit(self, widget):
+        print "quit"
+        Gtk.main_quit()
+
+    # Workaround to get Ctrl+C to terminate from command line
+    # ref: https://bugzilla.gnome.org/show_bug.cgi?id=622084#c12
+    signal.signal(signal.SIGINT, signal.SIG_DFL)
+
+start = Main()
+Gtk.main()