python: update python examples to modern python, Gst, and Glib versions

[experiments/gstreamer.git] / python / gst-trick-mode-looping-2.py

diff --git a/python/gst-trick-mode-looping-2.py b/python/gst-trick-mode-looping-2.py
index 920677d..a398331 100755 (executable)
--- a/python/gst-trick-mode-looping-2.py
+++ b/python/gst-trick-mode-looping-2.py
@@ -1,103 +1,114 @@
-#!/usr/bin/env python
-
+#!/usr/bin/env python3
+#
+# A simple "trick-mode" looping player.
+# Version 2, based on "about-to-finish" handling.
+#
+# Not working with speed rates other that 1.
+#
 # Get a test sample with:
 # youtube-dl -t http://www.youtube.com/watch?v=yWa-YXiSk2Y
 
 import sys
 
-import gobject
-gobject.threads_init()
+import gi
+gi.require_version('Gst', '1.0')
+from gi.repository import Gst
+Gst.init(None)
 
-import gst
+from gi.repository import GLib
 
 
 class Player:
-    def __init__(self, filename, rate):
-        self._filename = filename
+    def __init__(self, uri, rate):
+        self._uri = uri
         self._rate = rate
 
-        self._player = gst.element_factory_make("playbin2", "player")
-        self._player.set_property("uri", filename)
+        self._player = Gst.ElementFactory.make("playbin3", "player")
+        self._player.set_property("uri", uri)
         self._player.connect("about-to-finish", self.on_about_to_finish)
 
         bus = self._player.get_bus()
         bus.add_signal_watch()
+        bus.connect('message::error', self.on_error)
         bus.connect('message::state-changed', self.on_state_changed)
 
     def run(self):
-        self._player.set_state(gst.STATE_PLAYING)
-        loop = gobject.MainLoop()
-        loop.run()
+        self._player.set_state(Gst.State.PLAYING)
+        self.loop = GLib.MainLoop()
+        self.loop.run()
+
+    def quit(self):
+        self._player.set_state(Gst.State.NULL)
+        self.loop.quit()
 
     def on_about_to_finish(self, player):
         sys.stderr.write(".")
-        player.set_property("uri", self._filename)
+        self._player.set_property("uri", self._uri)
 
-        # XXX Ater the first iteration of the loop the playback rate is
-        # reset to normal. Do I need to re-set the rate here?
+        # XXX After the first iteration of the loop the playback rate is
+        # reset to 1. Do I need to re-set the rate here?
 
-        # If I uncomment the following line, the player hangs:
-        #self.set_rate(self._date)
+        # If I uncomment the following line, nothing changes:
+        #self.set_seek(0)
 
-        # And it hangs also if I set the seek_event manually using position=0:
-        #seek_event = gst.event_new_seek(self._rate,
-        #        gst.FORMAT_TIME,
-        #        gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
-        #        gst.SEEK_TYPE_SET, 0,
-        #        gst.SEEK_TYPE_NONE, 0)
-        #self._player.send_event(seek_event)
+    def on_error(self, bus, msg):
+        (err, debug) = msg.parse_error()
+        print("Error: %s" % err, debug)
+        self.quit()
 
     def on_state_changed(self, bus, msg):
         if msg.src != self._player:
             return
 
-        print 'on_state_changed'
+        print('on_state_changed')
         old_state, new_state, pending = msg.parse_state_changed()
-        print "%s -> %s" % (old_state, new_state)
-        if old_state == gst.STATE_READY and new_state == gst.STATE_PAUSED:
+        print("%s -> %s" % (old_state, new_state))
+        if old_state == Gst.State.READY and new_state == Gst.State.PAUSED:
             self.set_rate(self._rate)
 
     def set_rate(self, rate):
         self._rate = rate
-        try:
-            position, format = self._player.query_position(gst.FORMAT_TIME)
-        except:
-            position = 0
-
-        # Create the seek event
-        if rate > 0:
-            seek_event = gst.event_new_seek(rate,
-                    gst.FORMAT_TIME,
-                    gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
-                    gst.SEEK_TYPE_SET, position,
-                    gst.SEEK_TYPE_NONE, 0)
+        position = self._player.query_position(Gst.Format.TIME)[1]
+        self.set_seek(position, True)
+
+    def set_seek(self, position, flush=False):
+        flags = Gst.SeekFlags.SKIP | Gst.SeekFlags.ACCURATE
+
+        if flush:
+            flags |= Gst.SeekFlags.FLUSH
+
+        if self._rate >= 0:
+            seek_event = Gst.Event.new_seek(self._rate,
+                                            Gst.Format.TIME,
+                                            flags,
+                                            Gst.SeekType.SET, position,
+                                            Gst.SeekType.NONE, 0)
         else:
-            seek_event = gst.event_new_seek(rate,
-                    gst.FORMAT_TIME,
-                    gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
-                    gst.SEEK_TYPE_SET, 0,
-                    gst.SEEK_TYPE_SET, position)
+            seek_event = Gst.Event.new_seek(self._rate,
+                                            Gst.Format.TIME,
+                                            flags,
+                                            Gst.SeekType.NONE, 0,
+                                            Gst.SeekType.END, position)
 
         if seek_event:
             self._player.send_event(seek_event)
-            gst.info("rate set to %s" % rate)
+            Gst.info("rate set to %s" % self._rate)
         else:
-            gst.warining("change rate failed")
+            Gst.warining("change rate failed")
 
 
 def main(args):
     def usage():
-        sys.stdout.write("usage: %s <URI-OF-MEDIA-FILE>\n" % args[0])
+        sys.stdout.write("usage: %s <filename> <speedrate>\n" % args[0])
 
-    if len(args) != 2:
+    if len(args) != 3:
         usage()
         sys.exit(1)
 
-    if not gst.uri_is_valid(args[1]):
-        sys.stderr.write("Error: Invalid URI: %s\n" % args[1])
-        sys.exit(1)
+    uri = Gst.filename_to_uri(args[1])
+    rate = float(args[2])
 
-    player = Player(args[1], 3.0)
+    player = Player(uri, rate)
     player.run()
 
 if __name__ == '__main__':