[x265] [PATCH] consider skip cost in lookahead cost estimation

[Sagar Kotecha]

On Fri, Nov 6, 2015 at 11:46 AM, Deepthi Nandakumar <
deepthi at multicorewareinc.com> wrote:

> This patch got pushed accidentally, I think we still need some work here.
>
> On Fri, Nov 6, 2015 at 10:15 AM, <sagar at multicorewareinc.com> wrote:
>
>> # HG changeset patch
>> # User sagar at multicorewareinc.com
>> # Date 1446785051 -19800
>> #      Fri Nov 06 10:14:11 2015 +0530
>> # Node ID 4013786f7013c20b073cbd58ff02b64af8f4f15f
>> # Parent  39c35f175c8c515860ae4ea8ec75e15bc115d530
>> consider skip cost in lookahead cost estimation
>>
>> diff -r 39c35f175c8c -r 4013786f7013 source/encoder/slicetype.cpp
>> --- a/source/encoder/slicetype.cpp      Thu Nov 05 16:01:25 2015 +0530
>> +++ b/source/encoder/slicetype.cpp      Fri Nov 06 10:14:11 2015 +0530
>> @@ -2088,6 +2088,7 @@
>>      for (int i = 0; i < 1 + bBidir; i++)
>>      {
>>          int& fencCost = fenc->lowresMvCosts[i][listDist[i]][cuXY];
>> +        int skipCost = INT_MAX;
>>
>>          if (!bDoSearch[i])
>>          {
>> @@ -2129,6 +2130,9 @@
>>                  intptr_t stride = X265_LOWRES_CU_SIZE;
>>                  pixel *src = fref->lowresMC(pelOffset, mvc[idx],
>> subpelbuf, stride);
>>                  int cost = tld.me.bufSATD(src, stride);
>> +                /* Except for mv0 case, everyting else is likely to have
>> enough residual to not trigger the skip. */
>> +                if (!mvp.notZero() && bBidir)
>> +                    skipCost = cost;
>>
>
> I'm not sure this assumption is true at all. HEVC has merge MV candidates
> that make skip/merge much more cheaper. Where is mvp initialised - is this
> a bug?
>
>
It got pasted at wrong place while updating to recent tip, Will correct and
send patch soon.
​


>                  COPY2_IF_LT(mvpcost, cost, mvp, mvc[idx]);
>>              }
>>          }
>> @@ -2136,6 +2140,11 @@
>>          /* ME will never return a cost larger than the cost @MVP, so we
>> do not
>>           * have to check that ME cost is more than the estimated merge
>> cost */
>>          fencCost = tld.me.motionEstimate(fref, mvmin, mvmax, mvp, 0,
>> NULL, s_merange, *fencMV);
>> +        if (skipCost < 64 && skipCost < fencCost && bBidir)
>> +        {
>> +            fencCost = skipCost;
>> +            *fencMV = 0;
>> +        }
>>          COPY2_IF_LT(bcost, fencCost, listused, i + 1);
>>      }
>>
>> _______________________________________________
>> x265-devel mailing list
>> x265-devel at videolan.org
>> https://mailman.videolan.org/listinfo/x265-devel
>>
>
>
>
> --
> Deepthi Nandakumar
> Engineering Manager, x265
> Multicoreware, Inc
>
> _______________________________________________
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> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>
>
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