[VDPAU] ffmpeg and HEVC: Partial success, need help understanding problem

[Philip Langdale]

Although I've written what i think is correct reference handling code,
until I get that NumLongTermPictureSliceHeaderBits thing sorted out, I
don't think I can meaningfully test any of that.

So, I've been looking at an Intra-only sample, and I've actually got
something to appear on the screen - yay.

I'm not sure how to describe what I'm seeing in technical terms,
because I'm not familiar with all the HEVC jargon, but it shows the
video essentially being rendered in two parts (are these slices?) with
one part appearing to be rendered correctly, and the other rendered
half-way down the frame, and then looping back around with the bottom
part at the top.

Visually, this looks like part of the frame, roughly 'foreground
elements' in the right place, and the background offset incorrectly.

Right now I can't comprehend what I've done wrong to achieve this -
maybe incorrect scaling list transformations?

Thanks,

--phil