[x265] [PATCH algorithm modify] simplify coeff group clear when CG decide to not encode

[Steve Borho]

On 04/07, Min Chen wrote:
> # HG changeset patch
> # User Min Chen <chenm003 at 163.com>
> # Date 1428408208 -28800
> # Node ID d69e0b8066d7b146e1a4f1a17a9c6678e2740b30
> # Parent  095ed87526e5964ad45949ec81903704451d79f8
> simplify coeff group clear when CG decide to not encode

queued

> ---
>  source/common/quant.cpp |   23 +++++++++--------------
>  1 files changed, 9 insertions(+), 14 deletions(-)
> 
> diff -r 095ed87526e5 -r d69e0b8066d7 source/common/quant.cpp
> --- a/source/common/quant.cpp	Tue Apr 07 09:42:31 2015 +0530
> +++ b/source/common/quant.cpp	Tue Apr 07 20:03:28 2015 +0800
> @@ -585,6 +585,7 @@
>      TUEntropyCodingParameters codeParams;
>      cu.getTUEntropyCodingParameters(codeParams, absPartIdx, log2TrSize, bIsLuma);
>      const uint32_t cgNum = 1 << (codeParams.log2TrSizeCG * 2);
> +    const uint32_t cgStride = (trSize >> MLS_CG_LOG2_SIZE);
>  
>      /* TODO: update bit estimates if dirty */
>      EstBitsSbac& estBitsSbac = m_entropyCoder->m_estBitsSbac;
> @@ -601,7 +602,7 @@
>          const uint64_t cgBlkPosMask = ((uint64_t)1 << cgBlkPos);
>          memset(&cgRdStats, 0, sizeof(coeffGroupRDStats));
>  
> -        const int patternSigCtx = calcPatternSigCtx(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, (trSize >> MLS_CG_LOG2_SIZE));
> +        const int patternSigCtx = calcPatternSigCtx(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, cgStride);
>  
>          /* iterate over coefficients in each group in reverse scan order */
>          for (int scanPosinCG = cgSize - 1; scanPosinCG >= 0; scanPosinCG--)
> @@ -824,7 +825,7 @@
>               * of the significant coefficient group flag and evaluate whether the RD cost of the
>               * coded group is more than the RD cost of the uncoded group */
>  
> -            uint32_t sigCtx = getSigCoeffGroupCtxInc(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, (trSize >> MLS_CG_LOG2_SIZE));
> +            uint32_t sigCtx = getSigCoeffGroupCtxInc(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, cgStride);
>  
>              int64_t costZeroCG = totalRdCost + SIGCOST(estBitsSbac.significantCoeffGroupBits[sigCtx][0]);
>              costZeroCG += cgRdStats.uncodedDist;       /* add distortion for resetting non-zero levels to zero levels */
> @@ -841,23 +842,17 @@
>                  costCoeffGroupSig[cgScanPos] = SIGCOST(estBitsSbac.significantCoeffGroupBits[sigCtx][0]);
>  
>                  /* reset all coeffs to 0. UNCODE THIS COEFF GROUP! */
> -                for (int scanPosinCG = cgSize - 1; scanPosinCG >= 0; scanPosinCG--)
> -                {
> -                    scanPos = cgScanPos * cgSize + scanPosinCG;
> -                    uint32_t blkPos = codeParams.scan[scanPos];
> -                    if (dstCoeff[blkPos])
> -                    {
> -                        costCoeff[scanPos] = costUncoded[scanPos];
> -                        costSig[scanPos] = 0;
> -                    }
> -                    dstCoeff[blkPos] = 0;
> -                }
> +                const uint32_t blkPos = codeParams.scan[cgScanPos * cgSize];
> +                memset(&dstCoeff[blkPos + 0 * trSize], 0, 4 * sizeof(*dstCoeff));
> +                memset(&dstCoeff[blkPos + 1 * trSize], 0, 4 * sizeof(*dstCoeff));
> +                memset(&dstCoeff[blkPos + 2 * trSize], 0, 4 * sizeof(*dstCoeff));
> +                memset(&dstCoeff[blkPos + 3 * trSize], 0, 4 * sizeof(*dstCoeff));
>              }
>          }
>          else
>          {
>              /* there were no coded coefficients in this coefficient group */
> -            uint32_t ctxSig = getSigCoeffGroupCtxInc(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, (trSize >> MLS_CG_LOG2_SIZE));
> +            uint32_t ctxSig = getSigCoeffGroupCtxInc(sigCoeffGroupFlag64, cgPosX, cgPosY, cgBlkPos, cgStride);
>              costCoeffGroupSig[cgScanPos] = SIGCOST(estBitsSbac.significantCoeffGroupBits[ctxSig][0]);
>              totalRdCost += costCoeffGroupSig[cgScanPos];  /* add cost of 0 bit in significant CG bitmap */
>              totalRdCost -= cgRdStats.sigCost;             /* remove cost of significant coefficient bitmap */
> 
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-- 
Steve Borho