How do I set the cap in code

[William Johnston]

I tried that first. And I tried it again just now to make sure. The caps 
filter will not bind to EMPTY caps.

On 5/8/2020 1:27 AM, David Ing wrote:
> Setting caps directly on a pad is not always possible because the caps 
> are basically negotiated as the pipeline moves from the READY to 
> PAUSED state (IIRC).  Part of this negotiation involves communicating 
> with upstream and downstream elements to determine the caps at each 
> stage of the pipeline (at each pad).  I don't fully understand how it 
> works (I am just a novice).
>
> You do have an option to link your pad to a capsfilter 
> <https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-plugins/html/gstreamer-plugins-capsfilter.html> which 
> would then place constraints on the caps of your pad.  Basically the 
> caps negotiation will be forced to come up with something that fits 
> your caps filter, otherwise the pipeline will never enter the PAUSED 
> state (you would see some kind of error).
>
> On Thu, May 7, 2020 at 8:28 PM William Johnston <wgj at cast.uark.edu 
> <mailto:wgj at cast.uark.edu>> wrote:
>
>     I have and element that looks like this:
>
>     element: misbfixcoordinates1
>          pad: videosink
>              caps (writable):   video/x-raw, format=(string)RGB
>              template caps: video/x-raw, format=(string)RGB
>          pad: misbsink
>               caps (writable):   EMPTY
>               template caps: meta/klv
>          pad: videosrc
>              caps (writable):   video/x-raw, format=(string)RGB,
>     width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ],
>     framerate=(fraction)[ 0/1, 2147483647/1 ]
>              template caps: video/x-raw, format=(string)RGB
>          pad: misbsrc
>              caps (writable):   EMPTY
>              template caps: meta/klv
>
>     See those "EMPTY" caps? I want to set them to something else. I
>     thought
>     this would work:
>
>     GstPad*
>     misbsinkPad=gst_element_get_static_pad(misbfixcoordinates,"misbsink");
>     GstCaps* newCaps1=gst_caps_from_string("meta/klv");
>     gst_pad_set_caps(misbsinkPad,newCaps1);
>
>     But it doesn't change anything. Anyone know how to do this?
>
>     _______________________________________________
>     gstreamer-devel mailing list
>     gstreamer-devel at lists.freedesktop.org
>     <mailto:gstreamer-devel at lists.freedesktop.org>
>     https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20200508/df727aad/attachment.htm>