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 gobject
   9 gobject.threads_init()
  10
  11 import gst
  12
  13
  14 class Player:
  15     def __init__(self, filename, rate):
  16         self._filename = filename
  17         self._rate = rate
  18
  19         self._player = gst.element_factory_make("playbin2", "player")
  20         self._player.set_property("uri", filename)
  21
  22         bus = self._player.get_bus()
  23         bus.add_signal_watch()
  24         bus.connect('message::state-changed', self.on_state_changed)
  25
  26     def run(self):
  27         self._player.set_state(gst.STATE_PLAYING)
  28         loop = gobject.MainLoop()
  29         loop.run()
  30
  31     def on_state_changed(self, bus, msg):
  32         if msg.src != self._player:
  33             return
  34
  35         print 'on_state_changed'
  36         old_state, new_state, pending = msg.parse_state_changed()
  37         print "%s -> %s" % (old_state, new_state)
  38         if old_state == gst.STATE_READY and new_state == gst.STATE_PAUSED:
  39             self.set_rate(self._rate)
  40
  41     def set_rate(self, rate):
  42         self._rate = rate
  43         try:
  44             position, format = self._player.query_position(gst.FORMAT_TIME)
  45         except:
  46             position = 0
  47
  48         # Create the seek event
  49         if rate > 0:
  50             seek_event = gst.event_new_seek(rate,
  51                     gst.FORMAT_TIME,
  52                     gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
  53                     gst.SEEK_TYPE_SET, position,
  54                     gst.SEEK_TYPE_NONE, 0)
  55         else:
  56             seek_event = gst.event_new_seek(rate,
  57                     gst.FORMAT_TIME,
  58                     gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE,
  59                     gst.SEEK_TYPE_SET, 0,
  60                     gst.SEEK_TYPE_SET, position)
  61
  62         if seek_event:
  63             self._player.send_event(seek_event)
  64             gst.info("rate set to %s" % rate)
  65         else:
  66             gst.warining("change rate failed")
  67
  68
  69 def main(args):
  70     def usage():
  71         sys.stdout.write("usage: %s <URI-OF-MEDIA-FILE>\n" % args[0])
  72
  73     if len(args) != 2:
  74         usage()
  75         sys.exit(1)
  76
  77     if not gst.uri_is_valid(args[1]):
  78         sys.stderr.write("Error: Invalid URI: %s\n" % args[1])
  79         sys.exit(1)
  80
  81     player = Player(args[1], 3.0)
  82     player.run()
  83
  84 if __name__ == '__main__':
  85     sys.exit(main(sys.argv))