[VDPAU] Support H264 Hi10 via vdpau

[Christian König]

Am 29.10.2013 15:58, schrieb Stephen Warren:
> Christian König wrote at Tuesday, October 29, 2013 2:06 AM:
>> Am 28.10.2013 18:47, schrieb Stephen Warren:
>>> ... although actually looking at the new fields you're adding, won't
>>> the values *always* be "10" if the new profile is in use? I think you
>>> only need to do one of adding a new profile value, or adding new
>>> fields to the picture info struct, not both? Re: [PATCH 1/2] hi10:
>>> bump version in configure.ac
>> Nope, IIRC the spec says that those two fields *can* be larger than 0 if
>> you have Hi10P (e.g. represent 9 or 10 bits per luma/chroma component),
>> but they don't *have to*!
> I'm assuming that "but they don't have to" means:
>
> * If the stream is 8-bit, those fields can be 0, or 8.
>
> * If the stream is 9-/10-bit, those fields must be non-zero in order to
>    Indicate that.

Just the other way around. The H264 spec defines a field named 
"profile_idc" and only if this field has a certain value the two field 
bit_depth_luma_minus8 and bit_depth_chroma_minus8 are encoded in the SPS.

So if you have a Hi10P stream the bit_depth_(luma|chroma)_minus8 fields 
are encoded and *can* have values of 1 or 2 (indicating 9 or 10 bits of 
encoding) but they can also be zero (which indicates 8 bits encoding).

If you don't have a Hi10P stream then those two fields are inferred to 
be zero all the time.

>
> Presumably these fields don't vary throughout the stream, so I would expect
> the application algorithm to be:
>
> * If the stream is 8-bit, then use the existing VDP_DECODER_PROFILE_H264_*
>
> * If the stream is 9-/10-bit, then use the new VDP_DECODER_PROFILE_H264_HI10.
>
> So, perhaps it makes sense to add the new fields for the HI10 profile, but
> not the existing profiles.

Nope again, the profile can actually change at any time (this is pretty 
normal for TV broadcasts).

So what the media player application needs to do is:
1. Decode the headers (SPS/PPS/slice header).
2. Determine what profile we have based on the var "profile_idc" from 
the SPS.
3. Create the proper decoder or fall back to software decoding if this 
profile isn't supported by the hardware.

Christian.