[Libva] libva introductory article for newbies?

[Ibragimov Rinat]

Hi,

During making attempts to use VAAPI I faced with couple of difficulties
and then realized I have no high-level understanding of how it should
be used. Philosophy of libva, if you like. Is there exists some
introductory article about?

I don't understand why in i965 driver vaQueryImageFormats returns formats
in YUV-colorspace only (YV12, I420, NV12) but vaCreateImage have some code
with BGRA too. Is it allowed to create BGRA images? And so on. I tried to
search the web but failed to find answers. Code I found uses YV12 formats,
but I need to cope with RGB.

--
Rinat