In this case, the user only supplies a device and the frame context
is allocated internally by lavc.
(cherry picked from commit 5dd9a4b88b287bf8c93520afda7becb1ad0d1894)
Deprecates struct vaapi_context and the installed header vaapi.h,
to be removed at the next version bump.
(cherry picked from commit 851960f6f8cf1f946fe42fa36cf6598fac68072c)
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 123ccd07c55ccf075cc5daf5581237fbccb86bdb)
(cherry picked from commit 5e879b54a3a46817ea6c8a95a9aecab1176418b9)
(cherry picked from commit 0aec37e625821040c103641eec9c1e7a1efa2952)
(cherry picked from commit cfa4eb4fba782f3f37a33be997b27a91a07053c9)
