Causes of pipeline non-transitivity?
ystreet00 at gmail.com
Sun Apr 25 04:35:50 UTC 2021
On 25/4/21 1:39 am, amindfv--- via gstreamer-devel wrote:
> I frequently find myself confused and not knowing where to look when I'm able to build a pipeline from A->B, and a pipeline from B->C, but not from A->B->C.
> For example, I can go from v4l2src->glupload:
> $ gst-launch-1.0 v4l2src ! glupload ! glimagesink
> And I can go from glupload->glshader:
> $ gst-launch-1.0 videotestsrc ! glupload ! glshader fragment="\"`cat myshader.frag`\"" ! glimagesink
> But when I try and combine the two, I get an error:
> $ gst-launch-1.0 v4l2src ! glupload ! glshader fragment="\"`cat myshader.frag`\"" ! glimagesink
> WARNING: erroneous pipeline: could not link gluploadelement0 to glfiltershader0
> Where should I look when I hit issues like this? Is it always the case, for example, that A and B have negotiated a format that's incompatible with C? Or does it mean I need to provide more specific properties to A (or B, or C)? I don't see anything in gst-inspect that indicates they wouldn't all work together.
Add -v to gst-launch-1.0 to see the negotiated caps for successful cases.
In this case, you are probably missing a glcolorconvert element
(automatically contained within glimagesink) or a videoconvert element
as OpenGL only deals with RGBA buffers byt v4l2src likely produces some
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
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