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         seek_event = Gst.Event.new_seek(self._rate,
  45                                         Gst.Format.TIME,
  46                                         Gst.SeekFlags.FLUSH | Gst.SeekFlags.ACCURATE,
  47                                         Gst.SeekType.SET, 0,
  48                                         Gst.SeekType.NONE, 0)
  49         self._player.send_event(seek_event)
  50
  51     def on_error(self, bus, msg):
  52         (err, debug) = msg.parse_error()
  53         print "Error: %s" % err, debug
  54         self.quit()
  55
  56     def on_state_changed(self, bus, msg):
  57         if msg.src != self._player:
  58             return
  59
  60         print 'on_state_changed'
  61         old_state, new_state, pending = msg.parse_state_changed()
  62         print "%s -> %s" % (old_state, new_state)
  63         if old_state == Gst.State.READY and new_state == Gst.State.PAUSED:
  64             self.set_rate(self._rate)
  65
  66     def set_rate(self, rate):
  67         self._rate = rate
  68         position = self._player.query_position(Gst.Format.TIME)[1]
  69
  70         # Create the seek event
  71         seek_event = Gst.Event.new_seek(rate,
  72                                         Gst.Format.TIME,
  73                                         Gst.SeekFlags.FLUSH | Gst.SeekFlags.ACCURATE,
  74                                         Gst.SeekType.SET, position,
  75                                         Gst.SeekType.SET, -1)
  76
  77         if seek_event:
  78             self._player.send_event(seek_event)
  79             Gst.info("rate set to %s" % rate)
  80         else:
  81             Gst.warining("change rate failed")
  82
  83
  84 def main(args):
  85     def usage():
  86         sys.stdout.write("usage: %s <filename> <speedrate>\n" % args[0])
  87
  88     if len(args) != 3:
  89         usage()
  90         sys.exit(1)
  91
  92     uri = Gst.filename_to_uri(args[1])
  93     rate = float(args[2])
  94
  95     player = Player(uri, rate)
  96     player.run()
  97
  98 if __name__ == '__main__':
  99     sys.exit(main(sys.argv))