[VDPAU] [PATCH] Enable Lossless Decode Capabilities via VDPAU API

[José Hiram Soltren]

Hello,

On 12/04/2014 08:34 AM, Rémi Denis-Courmont wrote:
> Le 2014-12-04 01:44, Karthikeyan Sreenivasan a écrit :
>>> Extending the existing VdpPictureInfoH264 structure will perturb its ABI.
>>> If different software in the system uses the structure in a way that
>>> relies on its size (e.g., an array of VdpPictureInfoH264s, or a structure
>>> with a VdpPictureInfoH264 member and other members afterwards), and
>>> those are passed between software components that were compiled with
>>> different VdpPictureInfoH264 definitions, bad things will happen.
> 
> Fair enough. Lets not change the existing structure then.
> 
>>> For name: I'd recommend a name that describes the usage of the profile.
>>> E.g., VdpPictureInfoH264Predictive.  If we expect the structure to
>>> be useful for other profiles, then maybe a little more general; e.g.,
>>> VdpPictureInfoH264TransformBypass ?  But really, the bikeshed can be
>>> any color.
>>
>> The names correspond to the structure as such:
>>
>> 1. VdpPictureInfoH264Extended, Will contain the current transform_bypass
>> field and a struct_version so as to add more fields in the future if
>> need arises.
> 
> Adding a version number does not solve this the binary compatibility issue
> above. I would leave versioning out and rely on the decoder profile -
> effectively treating lossy H.264 and lossless H.264 as two different codecs.
> 
>> 2. VdpPictureInfoH264Predictive, will contain all the fields necessary for
>> VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE and the structure will not
>> change and will be used exclusively for Hi444PP [w/ or w/o lossless decode].
> 
> Yes.
> 

This seems fine to me.

If we only have one chance to add VdpPictureInfoH264Predictive as a structure
definition it should include all of the features related to the Hi444PP
profile. There are two. Lossless is one of them and separate color plane coding
is the other. I think that, reading through this paper [1], for our purposes a
frame level flag should be enough. So I propose adding to
VdpPictureInfoH264Predictive a single new flag, separate_color_planes.

If there are no other objections I hope we can get this checked in soon.

[1] http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=4106880

--José
-----------------------------------------------------------------------------------
This email message is for the sole use of the intended recipient(s) and may contain
confidential information.  Any unauthorized review, use, disclosure or distribution
is prohibited.  If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message.
-----------------------------------------------------------------------------------