Moves much of the setup logic for VAAPI decoding into lavc; the user
now need only provide the hw_frames_ctx.
(cherry picked from commit 123ccd07c5)
(cherry picked from commit 5e879b54a3)
(cherry picked from commit 0aec37e625)
(cherry picked from commit cfa4eb4fba)
The buffer map/unmap code was in an early version of this before it
was committed, but the unmap was never removed. While wrong, this
was harmless (and therefore unnoticed) because the buffers can't be
mapped at this point - all drivers just did nothing with the call.
When decoding interlaced pictures, the structure is reused to render
to the same surface twice. The parameter buffers were not being
cleared, which caused the i965 driver to error out.
Mark Thompson
Anton Khirnov