python/gst-trick-mode.py

   1 #!/usr/bin/env python
   2
   3 # Get a test sample with:
   4 # youtube-dl -t http://www.youtube.com/watch?v=yWa-YXiSk2Y
   5
   6 import sys
   7
   8 import gi
   9 gi.require_version('Gst', '1.0')
  10 from gi.repository import Gst
  11 Gst.init(None)
  12
  13 from gi.repository import GObject
  14 GObject.threads_init()
  15
  16
  17 class Player:
  18     def __init__(self, filename, rate):
  19         self._filename = filename
  20         self._rate = rate
  21
  22         self._player = Gst.ElementFactory.make("playbin", "player")
  23         self._player.set_property("uri", filename)
  24
  25         bus = self._player.get_bus()
  26         bus.add_signal_watch()
  27         bus.connect('message::state-changed', self.on_state_changed)
  28
  29     def run(self):
  30         self._player.set_state(Gst.State.PLAYING)
  31         loop = GObject.MainLoop()
  32         loop.run()
  33
  34     def on_state_changed(self, bus, msg):
  35         if msg.src != self._player:
  36             return
  37
  38         print 'on_state_changed'
  39         old_state, new_state, pending = msg.parse_state_changed()
  40         print "%s -> %s" % (old_state, new_state)
  41         if old_state == Gst.State.READY and new_state == Gst.State.PAUSED:
  42             self.set_rate(self._rate)
  43
  44     def set_rate(self, rate):
  45         self._rate = rate
  46         try:
  47             position, fmt = self._player.query_position(Gst.Format.TIME)
  48         except:
  49             position = 0
  50
  51         # Create the seek event
  52         if rate > 0:
  53             seek_event = Gst.Event.new_seek(rate,
  54                     Gst.Format.TIME,
  55                     Gst.SeekFlags.FLUSH | Gst.SeekFlags.ACCURATE,
  56                     Gst.SeekType.SET, position,
  57                     Gst.SeekType.NONE, 0)
  58         else:
  59             seek_event = Gst.Event.new_seek(rate,
  60                     Gst.Format.TIME,
  61                     Gst.SeekFlags.FLUSH | Gst.SeekFlags.ACCURATE,
  62                     Gst.SeekType.SET, 0,
  63                     Gst.SeekType.SET, position)
  64
  65         if seek_event:
  66             self._player.send_event(seek_event)
  67             Gst.info("rate set to %s" % rate)
  68         else:
  69             Gst.warining("change rate failed")
  70
  71
  72 def main(args):
  73     def usage():
  74         sys.stdout.write("usage: %s <URI-OF-MEDIA-FILE>\n" % args[0])
  75
  76     if len(args) != 2:
  77         usage()
  78         sys.exit(1)
  79
  80     if not Gst.uri_is_valid(args[1]):
  81         sys.stderr.write("Error: Invalid URI: %s\n" % args[1])
  82         sys.exit(1)
  83
  84     player = Player(args[1], 3.0)
  85     player.run()
  86
  87 if __name__ == '__main__':
  88     sys.exit(main(sys.argv))