[x265] [PATCH] Added support for multiple references

[Deepthi Devaki Akkoorath]

On Thu, Sep 26, 2013 at 11:58 AM, Deepthi Nandakumar <
deepthi at multicorewareinc.com> wrote:

> If this is the case, shouldnt you be changing maxRefL0 to maxNumReferences
> - 1 ??
>
>
No. P slices can still have maxNumReferences in L0.


>
> On Thu, Sep 26, 2013 at 10:55 AM, Deepthi Devaki Akkoorath <
> deepthidevaki at multicorewareinc.com> wrote:
>
>>
>> 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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>>> x265-devel at videolan.org
>>> https://mailman.videolan.org/listinfo/x265-devel
>>>
>>>
>>
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>>
>
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