[x265] [PATCH RFC] analysis: use macro and for-loop to simplify fast-intra

[dave]

On 08/14/2014 01:42 PM, Steve Borho wrote:
> # HG changeset patch
> # User Steve Borho <steve at borho.org>
> # Date 1408048681 18000
> #      Thu Aug 14 15:38:01 2014 -0500
> # Node ID 07138e6ac952c96d1e31f5490c44f4cfaf6ac12a
> # Parent  213f17c1492c5bf96c3f382e7beffe0c871a563c
> analysis: use macro and for-loop to simplify fast-intra
>
> this changes behavior a bit; it's trying both +/-1 offsets instead of just
> one. and it has to do one extra check at the end since mode 34 isn't reached
> by the other previous loops
>
> diff -r 213f17c1492c -r 07138e6ac952 source/encoder/analysis.cpp
> --- a/source/encoder/analysis.cpp	Thu Aug 14 09:43:39 2014 -0700
> +++ b/source/encoder/analysis.cpp	Thu Aug 14 15:38:01 2014 -0500
> @@ -1693,68 +1693,56 @@
>       bool modeHor;
>       pixel *cmp;
>       intptr_t srcStride;
> +
> +#define TRY_ANGLE(angle) \
> +    modeHor = angle < 18; \
> +    cmp = modeHor ? buf_trans : fenc; \
> +    srcStride = modeHor ? scaleTuSize : scaleStride; \
> +    sad = sa8d(cmp, srcStride, &tmp[(angle - 2) * predsize], scaleTuSize) << costShift; \
> +    bits = (mpms & ((uint64_t)1 << angle)) ? xModeBitsIntra(cu, angle, partOffset, depth) : rbits; \
> +    cost = m_rdCost.calcRdSADCost(sad, bits)
> +
>       if (m_param->bEnableFastIntra)
>       {
> -        int lowsad, highsad, asad = 0;
> -        uint32_t lowbits, highbits, amode, lowmode, highmode, abits = 0;
> -        uint64_t lowcost, highcost = MAX_INT64, acost = MAX_INT64;
> +        int asad = 0;
> +        uint32_t lowmode, highmode, amode, abits = 0;
> +        uint64_t acost = MAX_INT64;
>   
> -        for (mode = 4;mode < 35; mode += 5)
> +        /* pick the best angle, sampling at distance of 5 */
> +        for (mode = 5; mode < 35; mode += 5)
By starting with mode = 5, won't this miss mode 2 since only +/-2 is 
checked?  By starting from 4 the loop should end at 34.
>           {
> -            modeHor = (mode < 18);
> -            cmp = (modeHor ? buf_trans : fenc);
> -            srcStride = (modeHor ? scaleTuSize : scaleStride);
> -            sad = sa8d(cmp, srcStride, &tmp[(mode - 2) * predsize], scaleTuSize) << costShift;
> -            bits = !(mpms & ((uint64_t)1 << mode)) ? rbits : xModeBitsIntra(cu, mode, partOffset, depth);
> -            cost = m_rdCost.calcRdSADCost(sad, bits);
> +            TRY_ANGLE(mode);
>               COPY4_IF_LT(acost, cost, amode, mode, asad, sad, abits, bits);
>           }
> -        lowmode = amode - 2;
> -        modeHor = (lowmode < 18);
> -        cmp = (modeHor ? buf_trans : fenc);
> -        srcStride = (modeHor ? scaleTuSize : scaleStride);
> -        lowsad = sa8d(cmp, srcStride, &tmp[(lowmode - 2) * predsize], scaleTuSize) << costShift;
> -        lowbits = !(mpms & ((uint64_t)1 << lowmode)) ? rbits : xModeBitsIntra(cu, lowmode, partOffset, depth);
> -        lowcost = m_rdCost.calcRdSADCost(lowsad, lowbits);
> -        if (amode < 34)
> +
> +        /* refine best angle at distance 2, then distance 1 */
> +        for (uint32_t dist = 2; dist >= 1; dist--)
>           {
> -            highmode = amode + 2;
> -            modeHor = (highmode < 18);
> -            cmp = (modeHor ? buf_trans : fenc);
> -            srcStride = (modeHor ? scaleTuSize : scaleStride);
> -            highsad = sa8d(cmp, srcStride, &tmp[(highmode - 2) * predsize], scaleTuSize) << costShift;
> -            highbits = !(mpms & ((uint64_t)1 << highmode)) ? rbits : xModeBitsIntra(cu, highmode, partOffset, depth);
> -            highcost = m_rdCost.calcRdSADCost(highsad, highbits);
> +            lowmode = amode - dist;
> +            highmode = amode + dist;
> +
> +            X265_CHECK(lowmode >= 2 && lowmode <= 34, "low intra mode out of range\n");
> +            TRY_ANGLE(lowmode);
> +            COPY4_IF_LT(acost, cost, amode, lowmode, asad, sad, abits, bits);
> +
> +            X265_CHECK(highmode >= 2 && highmode <= 34, "high intra mode out of range\n");
> +            TRY_ANGLE(highmode);
> +            COPY4_IF_LT(acost, cost, amode, highmode, asad, sad, abits, bits);
>           }
> -        if (lowcost <= highcost)
> +
> +        if (amode == 33)
>           {
> -            mode = amode - 1;
> -            COPY4_IF_LT(acost, lowcost, amode, lowmode, asad, lowsad, abits, lowbits);
> +            TRY_ANGLE(34);
> +            COPY4_IF_LT(acost, cost, amode, 34, asad, sad, abits, bits);
>           }
> -        else
> -        {
> -            mode = amode + 1;
> -            COPY4_IF_LT(acost, highcost, amode, highmode, asad, highsad, abits, highbits);
> -        }
> -        modeHor = (mode < 18);
> -        cmp = (modeHor ? buf_trans : fenc);
> -        srcStride = (modeHor ? scaleTuSize : scaleStride);
> -        sad = sa8d(cmp, srcStride, &tmp[(mode - 2) * predsize], scaleTuSize) << costShift;
> -        bits = !(mpms & ((uint64_t)1 << mode)) ? rbits : xModeBitsIntra(cu, mode, partOffset, depth);
> -        cost = m_rdCost.calcRdSADCost(sad, bits);
> -        COPY4_IF_LT(acost, cost, amode, mode, asad, sad, abits, bits);
> +
>           COPY4_IF_LT(bcost, acost, bmode, amode, bsad, asad, bbits, abits);
>       }
>       else // calculate and search all intra prediction angles for lowest cost
>       {
>           for (mode = 2; mode < 35; mode++)
>           {
> -            modeHor = (mode < 18);
> -            cmp = (modeHor ? buf_trans : fenc);
> -            srcStride = (modeHor ? scaleTuSize : scaleStride);
> -            sad = sa8d(cmp, srcStride, &tmp[(mode - 2) * predsize], scaleTuSize) << costShift;
> -            bits = !(mpms & ((uint64_t)1 << mode)) ? rbits : xModeBitsIntra(cu, mode, partOffset, depth);
> -            cost = m_rdCost.calcRdSADCost(sad, bits);
> +            TRY_ANGLE(mode);
>               COPY4_IF_LT(bcost, cost, bmode, mode, bsad, sad, bbits, bits);
>           }
>       }
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