<div dir="ltr">I think that the caps filter <i>should</i> connect to any pad for which the <a href="https://gstreamer.freedesktop.org/documentation/gstreamer/gstpadtemplate.html?gi-language=c">static caps template</a> is compatible with the caps specified in the caps filter.<div><br></div><div>Some questions come to mind:</div><div><ul><li>Are you trying to connect the filter while the pipeline state is PAUSED or PLAYING? (That might not work.)</li><li>Are you trying to set caps while the pipeline state is PAUSED or PLAYING? (That might not work either.)</li></ul><div>I am not familiar with the gstreamer element that you are using ... and I am merely a gstreamer novice. Perhaps an expert would be more helpful.</div></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, May 8, 2020 at 8:58 AM William Johnston <<a href="mailto:wgj@cast.uark.edu">wgj@cast.uark.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>I tried that first. And I tried it again just now to make sure.
The caps filter will not bind to EMPTY caps. <br>
</p>
<div>On 5/8/2020 1:27 AM, David Ing wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>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).<br>
</div>
<div><br>
</div>
<div>You do have an option to link your pad to a <a href="https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-plugins/html/gstreamer-plugins-capsfilter.html" target="_blank">capsfilter</a> 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).</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, May 7, 2020 at 8:28 PM
William Johnston <<a href="mailto:wgj@cast.uark.edu" target="_blank">wgj@cast.uark.edu</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I
have and element that looks like this:<br>
<br>
element: misbfixcoordinates1<br>
pad: videosink<br>
caps (writable): video/x-raw, format=(string)RGB<br>
template caps: video/x-raw, format=(string)RGB<br>
pad: misbsink<br>
caps (writable): EMPTY<br>
template caps: meta/klv<br>
pad: videosrc<br>
caps (writable): video/x-raw, format=(string)RGB, <br>
width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], <br>
framerate=(fraction)[ 0/1, 2147483647/1 ]<br>
template caps: video/x-raw, format=(string)RGB<br>
pad: misbsrc<br>
caps (writable): EMPTY<br>
template caps: meta/klv<br>
<br>
See those "EMPTY" caps? I want to set them to something else.
I thought <br>
this would work:<br>
<br>
GstPad* <br>
misbsinkPad=gst_element_get_static_pad(misbfixcoordinates,"misbsink");<br>
GstCaps* newCaps1=gst_caps_from_string("meta/klv");<br>
gst_pad_set_caps(misbsinkPad,newCaps1);<br>
<br>
But it doesn't change anything. Anyone know how to do this?<br>
<br>
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