[Libva] [PATCH] mpeg2: fix incorrect slice_vertical_position from codec layers.

[Gwenole Beauchesne]

Hi,

2012/3/12 Gwenole Beauchesne <gb.devel at gmail.com>:
> Correctly emit slice_vertical_position, as per the definition from
> the bitstream, to the HW decoder (MFD_MPEG2_BSD_OBJECT).
>
> Add workaround for players that have not fixed their usage of
> slice_vertical_position. That field shall represent the slice vertical
> position as it comes from the bitstream.
>
> NOTE: I have not tested the ILK code path yet. Only SNB, IVB.

At least two other fixes are needed in the Gen driver to complete
MPEG-2 interlaced support. Codec layers (FFmpeg, GStreamer, etc.) also
require changes. slice_vertical_position is reportedly coming from the
bitstream, in order to please the PVR driver. This definition also
accomodates the VDPAU-based VA driver. So, let's align everybody on a
single definition. :)

The workaround part will be removed for libva-driver-intel 1.1.0+ or
1.2.0+ by next distribution releases. Probably Q3'12?

Regards,
Gwenole.