Instead of creating and adding VPP into the bin at setup, we wait until
we are sure the VA driver supports it. We know that when the VA video
context is received by the bin. Afterwards, it is decided to instanciate
and link the VPP or not.
This is more efficient and safer than waiting the VPP to fail and then
disable it.
https://bugzilla.gnome.org/show_bug.cgi?id=749554
Adding a new propery "disable-vpp", enabling it will prevent
the insertion of vaapipostproc child element.
This is helpful in debugging, specifically to narrow-down the
vaapidecodebin/vaapipostproc related negotiation issues.
No support for run-time disabling for now.
https://bugzilla.gnome.org/show_bug.cgi?id=745901
Add a "vaapidecodebin" element to vaapi plugins.
Child Elements: "vaapidecode ! queue ! vaapipostproc"
The Reasons for implementing a new bin element:
-- Help to Autoplug Hardware Accelerated Video Postprocessing element in playbin
with out any dependency to upstream gstreamer.
This is to overcome the *unacceptable* delay in upstream gstreamer to get new
features in. Eg: https://bugzilla.gnome.org/show_bug.cgi?id=687182.
Also customers using older gstreamer versions (1.2 and 1.4) will get the
benefit of autoplugging, hardware accelerated deinterlacing support etc.
-- Help to maintain a single thread implementation in vaapidecode.
This will result a dead-lock free vaapidecode in most of the cases.
More details here: https://bugzilla.gnome.org/show_bug.cgi?id=742605https://bugzilla.gnome.org/show_bug.cgi?id=745216
