examples: add an example to show looping using segments

Fixes #339772.
This commit is contained in:
Артём Попов 2010-09-07 14:28:14 +03:00 committed by Stefan Kost
parent 9f4a73d282
commit b921832369

198
examples/segments.py Executable file
View file

@ -0,0 +1,198 @@
#! /usr/bin/env python
# -*- coding: utf-8 -*-
# Segments.py
# Copyright (C) 2006 Artem Popov <artfwo@gmail.com>
#
# This example demonstrates segment seeking
# and seamless looping within playbin.
import pygst
pygst.require ("0.10")
import gst
import pygtk
pygtk.require ("2.0")
import gobject
class Looper (gobject.GObject):
__gproperties__ = {
"loop": (gobject.TYPE_BOOLEAN,
"loop",
"Whether to loop the segment",
False,
gobject.PARAM_READWRITE),
"start-pos": (gobject.TYPE_UINT64,
"start position",
"The segment start marker",
0,
0xfffffffffffffff, # max long possible
0,
gobject.PARAM_READWRITE),
"stop-pos": (gobject.TYPE_UINT64,
"stop position",
"The segment stop marker",
0,
0xfffffffffffffff, # max long possible
0,
gobject.PARAM_READWRITE),
} # __gproperties__
__gsignals__ = {
"stopped": (gobject.SIGNAL_RUN_LAST, gobject.TYPE_NONE, ()),
"position-updated": (gobject.SIGNAL_RUN_LAST, gobject.TYPE_NONE, (gobject.TYPE_FLOAT,)),
"error": (gobject.SIGNAL_RUN_LAST, gobject.TYPE_NONE, (gobject.TYPE_PYOBJECT,))
} # __gsignals__
def __init__ (self, location = None):
gobject.GObject.__init__ (self)
self.__playbin = gst.element_factory_make ("playbin")
self.__playbin.props.video_sink = gst.element_factory_make ("fakesink")
bus = self.__playbin.get_bus ()
bus.add_watch (self.__on_bus_message)
self.__loop = False
self.__start_pos = 0
self.__stop_pos = 0
self.__timeout_id = 0
if location:
self.load (location)
def load (self, location):
self.__playbin.props.uri = location
self.__start_position = 0
self.__stop_position = 0
def set_segment (self, start, stop):
self.props.start_pos = start
self.props.stop_pos = stop
def play (self):
if not (self.__start_pos or self.__stop_pos):
raise RuntimeError, "Cannot start playback, segment was not set!"
self.__playbin.set_state (gst.STATE_PLAYING)
def stop (self, silent = False):
self.__playbin.set_state (gst.STATE_NULL)
if not silent:
self.emit ("stopped")
def do_get_property (self, property):
if property.name == "loop":
return self.__loop
elif property.name == "start-pos":
return self.__start_pos
elif property.name == "stop-pos":
return self.__stop_pos
else:
raise AttributeError, "Unknown property %s" % property.name
def do_set_property (self, property, value):
if property.name == "loop":
self.__loop = value
elif property.name == "start-pos":
self.__start_pos = value
elif property.name == "stop-pos":
self.__stop_pos = value
else:
raise AttributeError, "Unknown property %s" % property.name
def do_stopped (self):
if self.__timeout_id:
gobject.source_remove (self.__timeout_id)
self.__timeout_id = 0
def __seek (self, start, stop, flush):
flags = gst.SEEK_FLAG_SEGMENT | gst.SEEK_FLAG_ACCURATE
if flush:
flags = flags | gst.SEEK_FLAG_FLUSH
self.__playbin.seek (1.0, gst.FORMAT_TIME, flags,
gst.SEEK_TYPE_SET, start,
gst.SEEK_TYPE_SET, stop)
def __on_timeout (self):
position = self.__playbin.query_position (gst.FORMAT_TIME) [0]
self.emit ("position-updated", float (position))
return True
def __on_bus_message (self, bus, message):
if message.type == gst.MESSAGE_ERROR:
error, debug = message.parse_error ()
self.stop () # this looks neccessary here
self.emit ("error", (error, debug))
elif message.type == gst.MESSAGE_NEW_CLOCK:
# we connect the timeout handler here to be sure that further queries succeed
interval = int ((self.__stop_position - self.__start_position) / (2 * gst.SECOND) + 50)
self.__timeout_id = gobject.timeout_add (interval, self.__on_timeout)
elif message.type == gst.MESSAGE_STATE_CHANGED:
old_state, new_state, pending = message.parse_state_changed ()
if old_state == gst.STATE_READY and new_state == gst.STATE_PAUSED and message.src == self.__playbin:
self.__seek (self.__start_pos, self.__stop_pos, True)
elif message.type == gst.MESSAGE_SEGMENT_DONE:
if self.__loop:
self.__seek (self.__start_pos, self.__stop_pos, False)
else:
src = self.__playbin.get_property ("source")
pad = src.get_pad ('src')
pad.push_event (gst.event_new_eos ())
# this is the good old way:
#
# pads = src.src_pads ()
# while True:
# try:
# pad = pads.next ()
# pad.push_event (gst.event_new_eos ())
# except:
# break
elif message.type == gst.MESSAGE_EOS:
self.stop ()
return True
mainloop = gobject.MainLoop ()
def on_looper_stopped (looper):
mainloop.quit ()
def on_looper_pos_updated (looper, position):
print round (position / gst.SECOND, 2)
def on_looper_error (looper, error_tuple):
error, debug = error_tuple
print "\n\n%s\n\n%s\n\n" % (error, debug)
mainloop.quit ()
if __name__ == "__main__":
import sys
if len (sys.argv) != 5:
print "Usage: %s <filename|uri> <start_seconds> <stop_seconds> <loop = 0|1>" % sys.argv [0]
sys.exit (1)
if "://" in sys.argv [1]:
uri = sys.argv [1]
else:
import os.path
uri = "file://" + os.path.abspath (sys.argv [1])
looper = Looper (uri)
looper.props.start_pos = long (sys.argv [2]) * gst.SECOND
looper.props.stop_pos = long (sys.argv [3]) * gst.SECOND
looper.props.loop = int (sys.argv [4])
looper.connect ("stopped", on_looper_stopped)
looper.connect ("position-updated", on_looper_pos_updated)
looper.connect ("error", on_looper_error)
looper.play ()
mainloop.run ()