Clarification sought over GStreamer Documentation
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Clarification sought over GStreamer Documentation
 
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I have studied section "8.4. Ghost pads" of "GStreamer Application
Development Manual (1.0.3)" - but I am not sure about the 'mechanics' of the code snippet (below) #include <gst/gst.h> int main (int argc, char *argv[]) { GstElement *bin, *sink; GstPad *pad; /* init */ gst_init (&argc, &argv); /* create element, add to bin */ Absolutely no problems with the code above. sink = gst_element_factory_make ("fakesink", "sink"); I understand that the above line is creating a new element of type 'fakesink', but I am not sure about the quoted "sink" in the parameters. Is that a key word (sink or src)? Is it the name that is to be given to something? I am reasonably sure that it is not the name of the object. bin = gst_bin_new ("mybin"); gst_bin_add (GST_BIN (bin), sink); /* add ghostpad */ pad = gst_element_get_static_pad (sink, "sink"); Again, I assume that the unquoted sink is a reference to 'our GstElement called sink. But again, the quoted "sink" - what is the purpose of that parameter? Is it referring to its relationship to the bin? or to where it wants to link on to in "Element1" (in Figure 8.2)? gst_element_add_pad (bin, gst_ghost_pad_new ("sink", pad)); I get the feeling that this "sink" is the leftmost sink in the bin of Figure 8.2. gst_object_unref (GST_OBJECT (pad)); Finally, I assume that once the pad has been used to link the bin's Pad to Element1's Pad, it is no longer required and can be freed. Correct? Is there something I should have read to understand this? Thank you for reading this far. Ian -- -- Ian Davidson -- Facts used in this message may or may not reflect an underlying objective reality. Facts are supplied for personal use only. Recipients quoting supplied information do so at their own risk. Facts supplied may vary in whole or part from widely accepted standards. While painstakingly researched, facts may or may not be indicative of actually occurring events or natural phenomena. The author accepts no responsibility for personal loss or injury resulting from memorisation and subsequent use. _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
RE: Clarification sought over GStreamer Documentation
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The second parameter of gst_element_factory_make is actually the name to be given to the new element. If you pass NULL as parameter, a unique name will be given:
http://gstreamer.freedesktop.org/data/doc/gstreamer/stable/gstreamer/html/GstElementFactory.html#gst-element-factory-make Regards, Daniela -----Original Message----- From: gstreamer-devel-bounces+daniela.muzzu=[hidden email] [mailto:gstreamer-devel-bounces+daniela.muzzu=[hidden email]] On Behalf Of Ian Davidson Sent: Sunday, December 16, 2012 3:41 PM To: Discussion of the development of and with GStreamer Subject: Clarification sought over GStreamer Documentation I have studied section "8.4. Ghost pads" of "GStreamer Application Development Manual (1.0.3)" - but I am not sure about the 'mechanics' of the code snippet (below) #include <gst/gst.h> int main (int argc, char *argv[]) { GstElement *bin, *sink; GstPad *pad; /* init */ gst_init (&argc, &argv); /* create element, add to bin */ Absolutely no problems with the code above. sink = gst_element_factory_make ("fakesink", "sink"); I understand that the above line is creating a new element of type 'fakesink', but I am not sure about the quoted "sink" in the parameters. Is that a key word (sink or src)? Is it the name that is to be given to something? I am reasonably sure that it is not the name of the object. bin = gst_bin_new ("mybin"); gst_bin_add (GST_BIN (bin), sink); /* add ghostpad */ pad = gst_element_get_static_pad (sink, "sink"); Again, I assume that the unquoted sink is a reference to 'our GstElement called sink. But again, the quoted "sink" - what is the purpose of that parameter? Is it referring to its relationship to the bin? or to where it wants to link on to in "Element1" (in Figure 8.2)? gst_element_add_pad (bin, gst_ghost_pad_new ("sink", pad)); I get the feeling that this "sink" is the leftmost sink in the bin of Figure 8.2. gst_object_unref (GST_OBJECT (pad)); Finally, I assume that once the pad has been used to link the bin's Pad to Element1's Pad, it is no longer required and can be freed. Correct? Is there something I should have read to understand this? Thank you for reading this far. Ian -- -- Ian Davidson -- Facts used in this message may or may not reflect an underlying objective reality. Facts are supplied for personal use only. Recipients quoting supplied information do so at their own risk. Facts supplied may vary in whole or part from widely accepted standards. While painstakingly researched, facts may or may not be indicative of actually occurring events or natural phenomena. The author accepts no responsibility for personal loss or injury resulting from memorisation and subsequent use. _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Clarification sought over GStreamer Documentation
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In reply to this post by Ian Davidson
Ian,
On Sun, Dec 16, 2012 at 12:41 PM, Ian Davidson <[hidden email]> wrote: I have studied section "8.4. Ghost pads" of "GStreamer Application Development Manual (1.0.3)" - but I am not sure about the 'mechanics' of the code snippet (below) Actually, it is the name of the object: http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make
Again, the reference documentation is your friend ;-) http://developer.gnome.org/gstreamer/stable/GstElement.html#gst-element-get-static-pad
The reference documentation: http://developer.gnome.org/gstreamer/stable/index.html Best regards, Tiago Katcipis
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