Best practice for pipeline to display video in Gtk4 app

General Discussion
1

I’ve developed an application in Python/Gtk4 for our vacation pictures and movies. The built-in video for Gtk4 is too limited, so I’m using gstreamer. This is on Manjaro Linux test branch so all Gtk and Gst packages are very recent.

I’ve done a very simple pipeline, basically connecting playbin3 straight to gtk4paintablesink embedded in a Gtk Picture… This is all working well. I was just wondering if this is an appropriate way to use things, letting the sink and Gtk take care of scaling etc.

Should i be putting things like videoconvert or other components into the pipeline to handle things?

Here’s the class where I set up the pipeline.

class GtkSink(Gtk.Picture):
    def __init__(self):
        super().__init__()
        # noinspection PyArgumentList,PyTypeChecker
        self.player = Gst.ElementFactory.make("playbin3", None)
        player_factory = self.player.get_factory()
        # noinspection SpellCheckingInspection
        video_sink: Gst.ChildProxy = player_factory.make('gtk4paintablesink', 'videosink')
        self.player.set_property("video-sink", video_sink)
        audio_sink: Gst.ChildProxy = player_factory.make('pulsesink', 'audiosink')
        # noinspection PyArgumentList
        role = Gst.Structure.new_from_string('props,media.role=video')
        audio_sink.set_property('stream-properties', role)
        role.free()
        self.player.set_property("audio-sink", audio_sink)
        paintable = video_sink.get_property('paintable')
        self.set_paintable(paintable)

Cheers,
Pat

2

Usually we wrap it I to glsinkbin, it will allow texture rendering (and dmanuf offloads recently). This will help avoid the software convert that playbin adds for you. It will enable more pixel formats too.

3

Thanks for the information. I’ll read up and try that. Please could you let me know what you wrap in glsinkbin? It sounds like you’re suggesting avoiding playbin?

4

No, create a glsinkbin, set its sink property to the GTK4 sink and then set playbin’s video-sink to the glsinkbin.

5

Thanks. I read up after the first response and ended up doing that. Thank you for the pointer though.

6

There’s a Python example in the repository btw. That might be helpful here.

7

Thanks. That’s a very useful example for carrying out the plumbing. I’d found the C equivalent, but couldn’t find the Python one. My original question was more about what to plumb rather than how, and that example completes the thread!