git.slaskete.net - python-gstreamer-examples/blob - example4.py

   1 #!/usr/bin/env python
   2 # Attempting to dynamically switch between input sources
   3
   4 # GdkX11 to get access to xid, GstVideo to get access to set_window_handle
   5 import gi, signal
   6 gi.require_version('Gtk', '3.0')
   7 gi.require_version('Gst', '1.0')
   8 gi.require_version('GstVideo', '1.0')
   9 from gi.repository import Gtk, Gst, GdkX11, GstVideo
  10
  11 class Main:
  12     def __init__(self):
  13
  14         # Create gui bits and bobs
  15
  16         self.mainwindow = Gtk.Builder()
  17         self.mainwindow.add_from_file("example4.glade")
  18
  19         signals = {
  20             "on_input1_clicked" : self.SetInput1,
  21             "on_input2_clicked" : self.SetInput2,
  22             "on_quit_clicked" : self.OnQuit,
  23         }
  24
  25         self.mainwindow.connect_signals(signals)
  26
  27         # Create GStreamer bits and bobs
  28
  29         # Initiate Gstreamer
  30         Gst.init(None)
  31
  32         # Some capabilities we want to share between different elements
  33         commoncaps = Gst.Caps.from_string("video/x-raw,width=1280,height=720,framerate=30/1")
  34
  35         # Set up the pipeline
  36         self.pipeline = Gst.Pipeline()
  37
  38         # Add a videotestsrc element, set it to pattern "ball" and some other properties
  39         self.ball = Gst.ElementFactory.make("videotestsrc", "ball")
  40         self.ball.set_property("pattern", "ball")
  41         self.ball.set_property("flip", True)
  42
  43         # Add a capsfilter that we want to apply to our ball
  44         self.ballcaps = Gst.ElementFactory.make("capsfilter", "ballcaps")
  45         self.ballcaps.set_property("caps", commoncaps)
  46
  47         # Webcam source
  48         self.webcam = Gst.ElementFactory.make("v4l2src", "webcam")
  49         self.webcam.set_property("device", "/dev/video0")
  50
  51         # Webcam capsfilter
  52         self.webcamcaps = Gst.ElementFactory.make("capsfilter", "webcamcaps")
  53         self.webcamcaps.set_property("caps", commoncaps)
  54
  55         # Add a videosink (where the playback happens)
  56         self.videosink = Gst.ElementFactory.make("autovideosink", "videosink")
  57         self.videosink.set_property("sync", False)
  58
  59         # Add initial elements to the pipeline
  60         self.pipeline.add(self.ball)
  61         self.pipeline.add(self.ballcaps)
  62         self.pipeline.add(self.videosink)
  63
  64         # Link the initial pipeline
  65         self.ball.link(self.ballcaps)
  66         self.ballcaps.link(self.videosink)
  67
  68         # Set up a bus to our pipeline to get notified when the video is ready
  69         self.bus = self.pipeline.get_bus()
  70         self.bus.enable_sync_message_emission()
  71         self.bus.connect("sync-message::element", self.OnSyncElement)
  72
  73         # Summon the window and connect the window's close button to quit
  74         self.window = self.mainwindow.get_object("mainwindow")
  75         self.window.connect("delete-event", Gtk.main_quit)
  76         self.window.show_all()
  77
  78         # Get window ID of the viewport widget from the GUI
  79         self.win_id = self.mainwindow.get_object("viewport").get_window().get_xid()
  80
  81         # Play!
  82         self.pipeline.set_state(Gst.State.PLAYING)
  83
  84
  85     # When we get a message that video is ready to display, set the
  86     # correct window id to hook it to our viewport
  87     def OnSyncElement(self, bus, message):
  88         if message.get_structure().get_name() == "prepare-window-handle":
  89             print("prepare-window-handle")
  90             message.src.set_window_handle(self.win_id)
  91
  92     def SetInput1(self, widget):
  93         print("Switch to input 1")
  94         # Halt current pipeline and tear it down
  95         self.pipeline.set_state(Gst.State.READY)
  96         self.webcamcaps.unlink(self.videosink)
  97         self.pipeline.remove(self.webcam)
  98         self.pipeline.remove(self.webcamcaps)
  99         # Construct new pipeline
 100         self.pipeline.add(self.ball)
 101         self.pipeline.add(self.ballcaps)
 102         self.ball.link(self.ballcaps)
 103         self.ballcaps.link(self.videosink)
 104         self.pipeline.set_state(Gst.State.PLAYING)
 105
 106     def SetInput2(self, widget):
 107         print("Switch to input 2")
 108         # Halt current pipeline and tear it down
 109         self.pipeline.set_state(Gst.State.READY)
 110         self.ballcaps.unlink(self.videosink)
 111         self.pipeline.remove(self.ball)
 112         self.pipeline.remove(self.ballcaps)
 113         # Construct new pipeline
 114         self.pipeline.add(self.webcam)
 115         self.pipeline.add(self.webcamcaps)
 116         self.webcam.link(self.webcamcaps)
 117         self.webcamcaps.link(self.videosink)
 118         self.pipeline.set_state(Gst.State.PLAYING)
 119
 120     def OnQuit(self, widget):
 121         print("quit")
 122         Gtk.main_quit()
 123
 124     # Workaround to get Ctrl+C to terminate from command line
 125     # ref: https://bugzilla.gnome.org/show_bug.cgi?id=622084#c12
 126     signal.signal(signal.SIGINT, signal.SIG_DFL)
 127
 128 start = Main()
 129 Gtk.main()