python/gst-trick-mode-looping-1.py

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