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

   1 #!/usr/bin/env python
   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 GObject
  17 GObject.threads_init()
  18
  19
  20 class Player:
  21     def __init__(self, uri, rate):
  22         self._rate = rate
  23
  24         self._player = Gst.ElementFactory.make("playbin", "player")
  25         self._player.set_property("uri", uri)
  26
  27         bus = self._player.get_bus()
  28         bus.add_signal_watch()
  29         bus.connect('message::eos', self.on_eos)
  30         bus.connect('message::error', self.on_error)
  31         bus.connect('message::state-changed', self.on_state_changed)
  32
  33     def run(self):
  34         self._player.set_state(Gst.State.PLAYING)
  35         self.loop = GObject.MainLoop()
  36         self.loop.run()
  37
  38     def quit(self):
  39         self._player.set_state(Gst.State.NULL)
  40         self.loop.quit()
  41
  42     def on_eos(self, bus, msg):
  43         sys.stderr.write(".")
  44         self.set_seek(0)
  45
  46     def on_error(self, bus, msg):
  47         (err, debug) = msg.parse_error()
  48         print "Error: %s" % err, debug
  49         self.quit()
  50
  51     def on_state_changed(self, bus, msg):
  52         if msg.src != self._player:
  53             return
  54
  55         print 'on_state_changed'
  56         old_state, new_state, pending = msg.parse_state_changed()
  57         print "%s -> %s" % (old_state, new_state)
  58         if old_state == Gst.State.READY and new_state == Gst.State.PAUSED:
  59             self.set_rate(self._rate)
  60
  61     def set_rate(self, rate):
  62         self._rate = rate
  63         position = self._player.query_position(Gst.Format.TIME)[1]
  64         self.set_seek(position)
  65
  66     def set_seek(self, position):
  67         flags = Gst.SeekFlags.SKIP | Gst.SeekFlags.FLUSH | Gst.SeekFlags.ACCURATE
  68
  69         if self._rate >= 0:
  70             seek_event = Gst.Event.new_seek(self._rate,
  71                                             Gst.Format.TIME,
  72                                             flags,
  73                                             Gst.SeekType.SET, position,
  74                                             Gst.SeekType.NONE, 0)
  75         else:
  76             seek_event = Gst.Event.new_seek(self._rate,
  77                                             Gst.Format.TIME,
  78                                             flags,
  79                                             Gst.SeekType.NONE, 0,
  80                                             Gst.SeekType.END, position)
  81
  82         if seek_event:
  83             self._player.send_event(seek_event)
  84             Gst.info("rate set to %s" % self._rate)
  85         else:
  86             Gst.warining("change rate failed")
  87
  88
  89 def main(args):
  90     def usage():
  91         sys.stdout.write("usage: %s <filename> <speedrate>\n" % args[0])
  92
  93     if len(args) != 3:
  94         usage()
  95         sys.exit(1)
  96
  97     uri = Gst.filename_to_uri(args[1])
  98     rate = float(args[2])
  99
 100     player = Player(uri, rate)
 101     player.run()
 102
 103 if __name__ == '__main__':
 104     sys.exit(main(sys.argv))