The main issue here was the use of [i] instead of [i * 3] for the 32x32
matrix. As part of fixing this, I changed the code to match that used
in vdpau_hevc, which I spent a lot of time verifying.

I also changed to calculating NumPocTotalCurr using the existing helper,
which is what vdpau does.
Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>