[x265] [PATCH] analysis: removed switch-case to read the best ref index

[Steve Borho]

On 05/25, ashok at multicorewareinc.com wrote:
> # HG changeset patch
> # User Ashok Kumar Mishra<ashok at multicorewareinc.com>
> # Date 1432566054 -19800
> #      Mon May 25 20:30:54 2015 +0530
> # Node ID 44f4024a71b921acc99d21a4e342ebe791d8128b
> # Parent  1335a2788c60d97c68d25250f847fe6a76fb0de6
> analysis: removed switch-case to read the best ref index

Two more follow-up patches for this series

1) I believe the X265_ANALYSIS_LOAD conditional can be removed from
   predInterSearch() by having callers limit the refmasks passed to the
   function when analysis is in load mode (removing one of the three
   redudant copies of the ME logic, --pme is the other redundant copy)

2) Analysis::compressInterCU_dist() should follow the same pattern of
   merge/skip, splits, then inter/intra, with only the inter/intra modes
   being distributed. This will re-align pmode to work like normal
   analysis and we'll be able to use the same or similar work avoidance
   logic to limit refs and intra preds, etc.

> diff -r 1335a2788c60 -r 44f4024a71b9 source/common/cudata.h
> --- a/source/common/cudata.h	Mon May 25 20:30:54 2015 +0530
> +++ b/source/common/cudata.h	Mon May 25 20:30:54 2015 +0530
> @@ -222,6 +222,8 @@
>      void     getNeighbourMV(uint32_t puIdx, uint32_t absPartIdx, InterNeighbourMV* neighbours) const;
>      void     getIntraTUQtDepthRange(uint32_t tuDepthRange[2], uint32_t absPartIdx) const;
>      void     getInterTUQtDepthRange(uint32_t tuDepthRange[2], uint32_t absPartIdx) const;
> +    uint32_t getBestRefIdx(uint32_t subPartIdx) const { return ((m_interDir[subPartIdx] & 1) << m_refIdx[0][subPartIdx]) |
> +                                                              (((m_interDir[subPartIdx] >> 1) & 1) << (m_refIdx[1][subPartIdx] + 16)); }
>  
>      uint32_t getNumPartInter() const              { return nbPartsTable[(int)m_partSize[0]]; }
>      bool     isIntra(uint32_t absPartIdx) const   { return m_predMode[absPartIdx] == MODE_INTRA; }
> diff -r 1335a2788c60 -r 44f4024a71b9 source/encoder/analysis.cpp
> --- a/source/encoder/analysis.cpp	Mon May 25 20:30:54 2015 +0530
> +++ b/source/encoder/analysis.cpp	Mon May 25 20:30:54 2015 +0530
> @@ -853,20 +853,7 @@
>              if (m_param->limitReferences & X265_REF_LIMIT_CU)
>              {
>                  CUData& cu = md.pred[PRED_2Nx2N].cu;
> -                int refMask;
> -                switch (cu.m_interDir[0])
> -                {
> -                case 1:
> -                    refMask = 1 << cu.m_refIdx[0][0];
> -                    break;
> -                case 2:
> -                    refMask = 1 << (cu.m_refIdx[1][0] + 16);
> -                    break;
> -                case 3:
> -                    refMask = 1 << cu.m_refIdx[0][0];
> -                    refMask |= 1 << (cu.m_refIdx[1][0] + 16);
> -                    break;
> -                }
> +                uint32_t refMask = cu.getBestRefIdx(0);
>                  allSplitRefs = splitRefs[0] = splitRefs[1] = splitRefs[2] = splitRefs[3] = refMask;
>              }
>  
> @@ -1101,22 +1088,7 @@
>          uint32_t puOffset = (g_puOffset[uint32_t(partSize)] << (g_unitSizeDepth - cu.m_cuDepth[0]) * 2) >> 4;
>          refMask = 0;
>          for (uint32_t puIdx = 0, subPartIdx = 0; puIdx < numPU; puIdx++, subPartIdx += puOffset)
> -        {
> -            uint32_t interDir = cu.m_interDir[subPartIdx];
> -            switch (interDir)
> -            {
> -            case 1:
> -                refMask |= 1 << cu.m_refIdx[0][subPartIdx];
> -                break;
> -            case 2:
> -                refMask |= 1 << (cu.m_refIdx[1][subPartIdx] + 16);
> -                break;
> -            case 3:
> -                refMask |= 1 << cu.m_refIdx[0][subPartIdx];
> -                refMask |= 1 << (cu.m_refIdx[1][subPartIdx] + 16);
> -                break;
> -            }
> -        }
> +            refMask |= cu.getBestRefIdx(subPartIdx);
>      }
>      
>      if (mightNotSplit)
> @@ -1254,20 +1226,7 @@
>              if (m_param->limitReferences & X265_REF_LIMIT_CU)
>              {
>                  CUData& cu = md.pred[PRED_2Nx2N].cu;
> -                int refMask;
> -                switch (cu.m_interDir[0])
> -                {
> -                case 1:
> -                    refMask = 1 << cu.m_refIdx[0][0];
> -                    break;
> -                case 2:
> -                    refMask = 1 << (cu.m_refIdx[1][0] + 16);
> -                    break;
> -                case 3:
> -                    refMask = 1 << cu.m_refIdx[0][0];
> -                    refMask |= 1 << (cu.m_refIdx[1][0] + 16);
> -                    break;
> -                }
> +                uint32_t refMask = cu.getBestRefIdx(0);
>                  allSplitRefs = splitRefs[0] = splitRefs[1] = splitRefs[2] = splitRefs[3] = refMask;
>              }
>  
> @@ -1390,22 +1349,7 @@
>          uint32_t puOffset = (g_puOffset[uint32_t(partSize)] << (g_unitSizeDepth - cu.m_cuDepth[0]) * 2) >> 4;
>          refMask = 0;
>          for (uint32_t puIdx = 0, subPartIdx = 0; puIdx < numPU; puIdx++, subPartIdx += puOffset)
> -        {
> -            uint32_t interDir = cu.m_interDir[subPartIdx];
> -            switch (interDir)
> -            {
> -            case 1:
> -                refMask |= 1 << cu.m_refIdx[0][subPartIdx];
> -                break;
> -            case 2:
> -                refMask |= 1 << (cu.m_refIdx[1][subPartIdx] + 16);
> -                break;
> -            case 3:
> -                refMask |= 1 << cu.m_refIdx[0][subPartIdx];
> -                refMask |= 1 << (cu.m_refIdx[1][subPartIdx] + 16);
> -                break;
> -            }
> -        }
> +            refMask |= cu.getBestRefIdx(subPartIdx);
>      }
>  
>      /* Copy best data to encData CTU and recon */
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-- 
Steve Borho