capabilities-playbin-example.py

#!/usr/bin/env python

import os
import gi
gi.require_version("Gst", "1.0")
from gi.repository import Gst, GObject, Gtk

class GTK_Main:
    def __init__(self):
        window = Gtk.Window(Gtk.WindowType.TOPLEVEL)
        window.set_title("Video-Player")
        window.set_default_size(500, 400)
        window.connect("destroy", Gtk.main_quit, "WM destroy")
        vbox = Gtk.VBox()
        window.add(vbox)
        hbox = Gtk.HBox()
        vbox.pack_start(hbox, False, False, 0)
        self.entry = Gtk.Entry()
        hbox.add(self.entry)
        self.button = Gtk.Button("Start")
        hbox.pack_start(self.button, False, False, 0)
        self.button.connect("clicked", self.start_stop)
        self.movie_window = Gtk.DrawingArea()
        vbox.add(self.movie_window)
        window.show_all()
        self.player = Gst.ElementFactory.make("playbin", "player")
        self.bin = Gst.Bin.new("my-bin")
        videoscale = Gst.ElementFactory.make("videoscale")
        videoscale.set_property("method", 1)
        pad = videoscale.get_static_pad("sink")
        ghostpad = Gst.GhostPad.new("sink", pad)
        ghostpad.set_active(True)
        self.bin.add_pad(ghostpad)
        caps = Gst.Caps.from_string("video/x-raw, width=720")
        filter = Gst.ElementFactory.make("capsfilter", "filter")
        filter.set_property("caps", caps)
        textoverlay = Gst.ElementFactory.make('textoverlay')
        textoverlay.set_property("text", "GNUTV")
        textoverlay.set_property("font-desc", "normal 14")
        # TypeError: object of type `GstTextOverlay' does not have property `halign'
        #textoverlay.set_property("halign", "right")
        # TypeError: object of type `GstTextOverlay' does not have property `valign'
        #textoverlay.set_property("valign", "top")
        conv = Gst.ElementFactory.make ("videoconvert", "conv")
        videosink = Gst.ElementFactory.make("autovideosink")
        
        self.bin.add(videoscale) 
        self.bin.add(filter) 
        self.bin.add(textoverlay)
        self.bin.add(conv)
        self.bin.add(videosink)

        videoscale.link(filter)
        filter.link(textoverlay)
        textoverlay.link(conv)
        conv.link(videosink)

        self.player.set_property("video-sink", self.bin)
        bus = self.player.get_bus()
        bus.add_signal_watch()
        bus.enable_sync_message_emission()
        bus.connect("message", self.on_message)
        bus.connect("sync-message::element", self.on_sync_message)

    def start_stop(self, w):
        if self.button.get_label() == "Start":
            filepath = self.entry.get_text().strip()
            if os.path.exists(filepath):
                filepath = os.path.realpath(filepath)
                self.button.set_label("Stop")
                self.player.set_property("uri", "file://" + filepath)
                self.player.set_state(Gst.State.PLAYING)
        else:
            self.player.set_state(Gst.State.NULL)
            self.button.set_label("Start")

    def on_message(self, bus, message):
        typ = message.type
        if typ == Gst.MessageType.EOS:
            self.player.set_state(Gst.State.NULL)
            self.button.set_label("Start")
        elif typ == Gst.MessageType.ERROR:
            self.player.set_state(Gst.State.NULL)
            self.button.set_label("Start")
            err, debug = message.parse_error()
            print("Error: %s" % err, debug)

    def on_sync_message(self, bus, message):
        if message.structure is None:
            return
        message_name = message.structure.get_name()
        if message_name == "prepare-xwindow-id":
            imagesink = message.src
            imagesink.set_property("force-aspect-ratio", True)
            imagesink.set_xwindow_id(self.movie_window.window.xid)

GObject.threads_init()
Gst.init(None)        
GTK_Main()
Gtk.main()