10 gobject.threads_init()
18 WIDTH, HEIGHT = 640, 480
22 class PyGstBufferDraw(gst.Element):
23 _sinkpadtemplate = gst.PadTemplate ("sink",
26 gst.caps_from_string ("video/x-raw-rgb,bpp=32,depth=32,blue_mask=-16777216,green_mask=16711680, red_mask=65280, alpha_mask=255,width=[ 1, 2147483647 ],height=[ 1, 2147483647 ],framerate=[ 0/1, 2147483647/1 ]"))
27 _srcpadtemplate = gst.PadTemplate ("src",
30 gst.caps_from_string ("video/x-raw-rgb,bpp=32,depth=32,blue_mask=-16777216,green_mask=16711680, red_mask=65280, alpha_mask=255,width=[ 1, 2147483647 ],height=[ 1, 2147483647 ],framerate=[ 0/1, 2147483647/1 ]"))
33 gst.Element.__init__(self)
35 self.sinkpad = gst.Pad(self._sinkpadtemplate, "sink")
36 self.sinkpad.set_chain_function(self.chainfunc)
37 self.sinkpad.set_event_function(self.eventfunc)
38 self.sinkpad.set_getcaps_function(gst.Pad.proxy_getcaps)
39 self.sinkpad.set_setcaps_function(gst.Pad.proxy_setcaps)
40 self.add_pad (self.sinkpad)
42 self.srcpad = gst.Pad(self._srcpadtemplate, "src")
44 self.srcpad.set_event_function(self.srceventfunc)
45 self.srcpad.set_query_function(self.srcqueryfunc)
46 self.srcpad.set_getcaps_function(gst.Pad.proxy_getcaps)
47 self.srcpad.set_setcaps_function(gst.Pad.proxy_setcaps)
48 self.add_pad (self.srcpad)
50 def chainfunc(self, pad, buffer):
52 outbuf = buffer.copy_on_write ()
54 return self.srcpad.push (outbuf)
58 def eventfunc(self, pad, event):
59 return self.srcpad.push_event (event)
61 def srcqueryfunc (self, pad, query):
62 return self.sinkpad.query (query)
63 def srceventfunc (self, pad, event):
64 return self.sinkpad.push_event (event)
66 def draw_on (self, buf):
69 width = caps[0]['width']
70 height = caps[0]['height']
71 framerate = caps[0]['framerate']
72 surface = cairo.ImageSurface.create_for_data (buf, cairo.FORMAT_ARGB32, width, height, 4 * width)
73 ctx = cairo.Context(surface)
75 print "Failed to create cairo surface for buffer"
84 radius = float (min (width, height)) * 0.25
85 ctx.set_source_rgba (0.0, 0.0, 0.0, 0.9)
86 ctx.move_to (center_x, center_y)
87 ctx.arc (center_x, center_y, radius, 0, 2.0*pi)
90 ctx.set_source_rgba (1.0, 1.0, 1.0, 1.0)
91 ctx.set_font_size(0.3 * radius)
93 extents = ctx.text_extents (txt)
94 ctx.move_to(center_x - extents[2]/2, center_y + extents[3]/2)
99 print "Failed cairo render"
100 traceback.print_exc()
102 gobject.type_register(PyGstBufferDraw)
104 pipe = gst.Pipeline()
105 vt = gst.element_factory_make ("videotestsrc")
106 cf = gst.element_factory_make ("capsfilter")
107 c1 = PyGstBufferDraw()
108 color = gst.element_factory_make ("ffmpegcolorspace")
109 scale = gst.element_factory_make ("videoscale")
110 q1 = gst.element_factory_make ("queue")
111 sink = gst.element_factory_make ("autovideosink")
113 caps = gst.caps_from_string ("video/x-raw-rgb,width=%d,height=%d,framerate=%d/1" % (WIDTH, HEIGHT, FRAMERATE))
114 cf.set_property ("caps", caps)
116 vt.set_property ("num-buffers", FRAMES)
118 pipe.add (vt, cf, c1, q1, color, scale, sink)
119 gst.element_link_many (vt, cf, c1, q1, color, scale, sink)
121 def on_eos (bus, msg):
125 bus.add_signal_watch()
126 bus.connect('message::eos', on_eos)
128 pipe.set_state (gst.STATE_PLAYING)
130 mainloop = gobject.MainLoop()
136 pipe.set_state (gst.STATE_NULL)
137 pipe.get_state (gst.CLOCK_TIME_NONE)