[x265] [PATCH] Added support for multiple references

[Deepthi Devaki Akkoorath]

The current implementation is like this:

numNegPics + numPosPics = maxNumReferences.
For P slices: numNegPics = maxNumReferences
For B slices: numNegPics = maxNumReferences - 1, numPosPics = 1

With the above logic ,    maxDecPicBuffering = 1(current) +
maxNumReferences    seems to be correct

- Deepthi


On Thu, Sep 26, 2013 at 7:05 AM, Steve Borho <steve at borho.org> wrote:

>
>
>
> On Wed, Sep 25, 2013 at 6:22 PM, Olivier Lapicque <olapicque at nvidia.com>wrote:
>
>> Yeah, it seems like it should be more like:****
>>
>> MaxDecPicBuffering = 1 (Current) + MaxNumNegativePics (=MaxForwardRefs) +
>> MaxNumPositivePics (=MaxBackwardRefs)****
>>
>> ** **
>>
>> With assuming ****
>>
>> MaxNumNegativePics = maxNumReferences (really MaxNumForwardReferences)***
>> *
>>
>> MaxNumPositivePics = limited by gop structure (reordering) ****
>>
>> ** **
>>
>> For a standard GOP structure with non-reference B-frames (coded
>> order=Pbbb):****
>>
>> MaxDecPicBuffering = 1 (Current) + maxNumReferences + 1 ( 1P available as
>> backward reference, limiting NumPositivePics to 1) = 2+maxNumReferences**
>> **
>>
>> ** **
>>
>> For 1-deep B-pyramid where the middle-B is a reference (display
>> order=bBbP, coded order=PBbb):****
>>
>> MaxDecPicBuffering = 1 (Current) + maxNumReferences + 2 (1P + 1B
>> available as backward references, limiting NumPositivePics to 1) =
>> 3+maxNumReferences
>>
>
> I think the current logic is correct.  We don't yet support B-pyramid so I
> believe:
>
> maxPositivePics = 1
> maxNegativePics = max(1, maxNumReferences - maxPositivePics).
>
> The max consecutive bframes count (--bframes) doesn't influence
> MaxDecPicBuffering since non-referenced B frames can be flushed from the
> DPB as soon as they are displayed.
>
> Deepthi D, can you confirm this is true?
>
> Thanks,
>
> --
> Steve Borho
>
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