They have been deprecated for a decade, yet you're forced to explicitly
deal with them at every step, or they will break your shit.
FFmpeg insists on keeping them, because libavfilter is too stupid to
deal with color ranges properly. Ridiculous.
For some braindead reason, Microsoft decided to prevent you from
dynamically loading system libraries. This makes portability harder.
And we're talking about portability between Microsoft OSes!
Unfortunately quite a mess, in particular due to the need to have some
compatibility with the old API. (The old API will be supported only in
short term.)
Until now, the texture pointer was stored in plane 1, and the texture
array index was in plane 2. Move this down to plane 0 and plane 1. This
is to align it to the new WIP D3D11 decoding API in Libav, where we
decided that there is no reason to avoid setting plane 0, and that it
would be less weird to start at plane 0.
FFmpeg could crash with vaapi (new) and --vo=opengl + interpolation.
It seems the actual surface count the old vaapi code uses (and which
usually never exceeded the preallocated amount) was higher than what
was used for the new vaapi code, so just correct that. The d3d helpers
also had weird code that bumped the real pool size, fix them as well.
Why this would result in an assertion failure instead of a proper error,
who knows.