python/gst-trick-mode-looping-3.py

   1 #!/usr/bin/env python3
   2 #
   3 # A simple "trick-mode" looping player.
   4 # Version 3, based on segment seeking.
   5 #
   6 # TODO: the trickmodes work way better but the looping functionality
   7 # needs to be fixed.
   8 #
   9 # Get a test sample with:
  10 # youtube-dl -t http://www.youtube.com/watch?v=yWa-YXiSk2Y
  11
  12 import sys
  13
  14 import gi
  15 gi.require_version('Gst', '1.0')
  16 from gi.repository import Gst
  17 Gst.init(None)
  18
  19 from gi.repository import GLib
  20
  21
  22 class Player:
  23     def __init__(self, uri, rate):
  24         self._rate = rate
  25
  26         self._player = Gst.ElementFactory.make("playbin", "player")
  27         self._player.set_property("uri", uri)
  28
  29         bus = self._player.get_bus()
  30         bus.add_signal_watch()
  31         bus.connect('message::error', self.on_error)
  32         bus.connect('message::segment-done', self.on_segment_done)
  33         bus.connect('message::state-changed', self.on_state_changed)
  34
  35     def run(self):
  36         self._player.set_state(Gst.State.PLAYING)
  37         self.loop = GLib.MainLoop()
  38         self.loop.run()
  39
  40     def quit(self):
  41         self._player.set_state(Gst.State.NULL)
  42         self.loop.quit()
  43
  44     def on_segment_done(self, bus, msg):
  45         self.set_seek(0)
  46
  47     def on_error(self, bus, msg):
  48         (err, debug) = msg.parse_error()
  49         print("Error: %s" % err, debug)
  50         self.quit()
  51
  52     def on_state_changed(self, bus, msg):
  53         if msg.src != self._player:
  54             return
  55
  56         print('on_state_changed')
  57         old_state, new_state, pending = msg.parse_state_changed()
  58         print("%s -> %s" % (old_state, new_state))
  59         if old_state == Gst.State.READY and new_state == Gst.State.PAUSED:
  60             self.set_rate(self._rate)
  61
  62     def set_rate(self, rate):
  63         self._rate = rate
  64         self.set_seek(0, True)
  65
  66     def set_seek(self, position, flush=False):
  67         flags = Gst.SeekFlags.SEGMENT | Gst.SeekFlags.SKIP | Gst.SeekFlags.ACCURATE
  68
  69         if flush:
  70             flags |= Gst.SeekFlags.FLUSH
  71
  72         if self._rate >= 0:
  73             seek_event = Gst.Event.new_seek(self._rate,
  74                                             Gst.Format.TIME,
  75                                             flags,
  76                                             Gst.SeekType.SET, position,
  77                                             Gst.SeekType.NONE, 0)
  78         else:
  79             seek_event = Gst.Event.new_seek(self._rate,
  80                                             Gst.Format.TIME,
  81                                             flags,
  82                                             Gst.SeekType.NONE, 0,
  83                                             Gst.SeekType.END, position)
  84
  85         if seek_event:
  86             self._player.send_event(seek_event)
  87             Gst.info("rate set to %s" % self._rate)
  88         else:
  89             Gst.warining("change rate failed")
  90
  91
  92 def main(args):
  93     def usage():
  94         sys.stdout.write("usage: %s <filename> <speedrate>\n" % args[0])
  95
  96     if len(args) != 3:
  97         usage()
  98         sys.exit(1)
  99
 100     uri = Gst.filename_to_uri(args[1])
 101     rate = float(args[2])
 102
 103     player = Player(uri, rate)
 104     player.run()
 105
 106 if __name__ == '__main__':
 107     sys.exit(main(sys.argv))