compositor: fails to negotiate when compositing alpha and non alpha formats

[philippe renon]

Hi,
I have a pipeline where I am trying to composite to branches:- ksvideosrc that produces I420 frames (with no alpha channel)- textrender that produces RGBA frames
If the textrender branch is the first to produce a frame that reaches the compositor then the pipeline works fine.On the other hand, if the ksvideosrc is first then the pipeline fails with a caps negotation failure happening in the textrender branch.
I can fix the pipeline by adding a videoconvert element in the ksvideosrc branch and forcing conversion to RGBA but it does not feel right.
Is this a bug in compositor ?

Philippe.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20151103/bce2dc9b/attachment.html>