[gst-devel] Problem inheriting from GstVideoSink class

[Maupin, Chase]

I just wanted to let everyone know that I figured out my problem.  I did not have the sync member in the base sync class set which is why I was not seeing frames dropped.

Sincerely,
Chase Maupin
Software Applications
Catalog DSP Products
e-mail: chase.maupin at ti.com
phone: (281) 274-3285
 

> -----Original Message-----
> From: gstreamer-devel-bounces at lists.sourceforge.net 
> [mailto:gstreamer-devel-bounces at lists.sourceforge.net] On 
> Behalf Of Maupin, Chase
> Sent: Wednesday, September 03, 2008 9:36 AM
> To: gstreamer-devel at lists.sourceforge.net
> Subject: [gst-devel] Problem inheriting from GstVideoSink class
> 
> All,
> 
> I am working on writing a video sink and I am trying to 
> inherit from the GstVideoSink class so that I get 
> functionality such as dropping frames that are past their 
> display time.  I have a reference video sink which uses this 
> class and for experimentation purposes I placed a 1 second 
> delay in the render function.  I observed that the display 
> times in the buffers given to the sink were now 1 second 
> apart and the video was skipping as I would expect.  I put 
> the same delay in my video sink and I am still seeing time 
> stamps that are only .033 seconds apart.  Basically the 
> frames that should have been thrown away during the delay are 
> just getting queued up and arrive in order after the delay.
> 
> I am doing the following to inherit from the GstVideoSink class:
> 
> - In my .c code I am using
> 	#define _do_init(bla) \
> 		GST_DEBUG_CATEGORY_INIT 
> (gst_tidmaivideosink_debug, "TIDmaiVideoSink", 0, 
> "TIDmaiVideoSink Element");
> 	GST_BOILERPLATE_FULL (GstTIDmaiVideoSink, 
> gst_tidmaivideosink, GstVideoSink, GST_TYPE_VIDEO_SINK, _do_init);
> 
> - In my .h code I am doing the following
> 	- Define a member GstVideoSink videosink as the first 
> member of my GstTIDmaiVideoSink structure
> 	- Define a member GstVideoSinkClass parent_class as the 
> first member of my GstTIDmaiVideoSinkClass structure
> 
> Lastly, in my makefile I am adding $(GST_BASE_LIBS), 
> $(GST_PLUGINS_BASE_LIBS) and -lgstvideo-0.10 to my LIBADD variable.
> 
> Even with all of this I don't seem to be getting the lateness 
> property set correctly.  I ran the compile of my plugin and 
> stopped after the pre-processor to see what the 
> GST_BOILERPLATE_FULL macro was expanding out to.  I see the 
> following output:
> 
> static void gst_tidmaivideosink_base_init (gpointer g_class); 
> static void gst_tidmaivideosink_class_init 
> (GstTIDmaiVideoSinkClass *g_class); static void 
> gst_tidmaivideosink_init (GstTIDmaiVideoSink *object, 
> GstTIDmaiVideoSinkClass *g_class); static GstVideoSinkClass 
> *parent_class = ((void *)0); static void 
> gst_tidmaivideosink_class_init_trampoline (gpointer g_class, 
> gpointer data) {
>   parent_class = (GstVideoSinkClass *) 
> g_type_class_peek_parent (g_class);
>   gst_tidmaivideosink_class_init ((GstTIDmaiVideoSinkClass 
> *)g_class); } GType gst_tidmaivideosink_get_type (void); 
> GType gst_tidmaivideosink_get_type (void) {
>   static GType object_type = 0;
>   if ((__builtin_expect (__extension__ ({ int 
> _g_boolean_var_; if (object_type == 0) _g_boolean_var_ = 1; 
> else _g_boolean_var_ = 0; _g_boolean_var_; }), 0))) { 
>     static const GTypeInfo object_info = { sizeof 
> (GstTIDmaiVideoSinkClass), gst_tidmaivideosink_base_init, 
> ((void *)0), gst_tidmaivideosink_class_init_trampoline, 
> ((void *)0), ((void *)0), sizeof (GstTIDmaiVideoSink), 0, 
> (GInstanceInitFunc) gst_tidmaivideosink_init };
>   object_type = g_type_register_static 
> ((gst_video_sink_get_type()), "GstTIDmaiVideoSink", 
> &object_info, (GTypeFlags) 0);
>  (void) __extension__ ({ if (gst_tidmaivideosink_debug == 
> ((void *)0)) gst_tidmaivideosink_debug = 
> _gst_debug_category_new ("TIDmaiVideoSink",0,"TIDmaiVideoSink 
> Element"); });; } return object_type; };
> 
> Notice that object_type is being set to use 
> gst_video_sink_get_type() for the parent class.
> 
> Can anyone please tell me what I am missing about inheriting 
> from the VideoSink class and why I don't seem to be getting 
> the default max_lateness behavior that the VideoSink class 
> defines.  I will provide full source code if needed but I 
> didn't want to make this e-mail too ugly to begin.
> 
> Sincerely,
> Chase Maupin
> Software Applications
> Catalog DSP Products
> e-mail: chase.maupin at ti.com
> 
> 
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