This link only shows a single VAAPI filter, tonemap_vaapi, and funny
enough, that filter isn't showing up as one of my enabled filters for my
ffmpeg build under the -filters option.
Can someone help me sort out
1. What determines is a defined filter (allfilters.c) makes it into the
-filters option on a compiled ffmpeg
2. How do I get a working build with the transpose_vaapi filter recognized
3. Where do I find documentation for the vaapi filters that are missing
from the documentation link that I provided.