va: postproc: cannot negotiate different caps features
With !2045 (merged) now this pipeline doesn't work anymore:
gst-launch-1.0 filesrc location=~/file.mp4 ! parsebin ! vah264dec ! video/x-raw\(memory:VAMemory\) ! vapostproc ! xvimagesink
Because now all the caps features that are not part of the processed caps are removed, so no other possible caps features are negotiated in the other direction.
Reverting commit f7eb93e2 the functionality is recovered.
Still there's room for improvement: it is possible to remove, from the caps template to append, the structures with caps features from the received caps to process.