[x265] [PATCH] rc: fix chroma qp and chroma lambda derivations

[Deepthi Nandakumar]

This is missing the constants table for HIGH_BIT_DEPTH.

On Fri, Dec 5, 2014 at 12:23 PM, <aarthi at multicorewareinc.com> wrote:

> # HG changeset patch
> # User Aarthi Thirumalai
> # Date 1417675781 -19800
> #      Thu Dec 04 12:19:41 2014 +0530
> # Node ID 97f0f0e5d7efd1f883283617f657875340f381a8
> # Parent  511dde5ac1deee96a0105bb87e14670ef5ed72a6
> rc: fix chroma qp and chroma lambda derivations.
>
> fix the chroma qp values for Main10 profile, derive chroma qp from luma qp
> values
> according to the HEVC spec.
> improves quality at high qps.
>
> diff -r 511dde5ac1de -r 97f0f0e5d7ef source/encoder/rdcost.h
> --- a/source/encoder/rdcost.h   Thu Dec 04 12:43:06 2014 +0530
> +++ b/source/encoder/rdcost.h   Thu Dec 04 12:19:41 2014 +0530
> @@ -50,19 +50,24 @@
>      void setQP(const Slice& slice, int qp)
>      {
>          m_qp = qp;
> -
> +        int qpCb, qpCr;
>          /* Scale PSY RD factor by a slice type factor */
>          static const uint32_t psyScaleFix8[3] = { 300, 256, 96 }; /* B,
> P, I */
>          m_psyRd = (m_psyRdBase * psyScaleFix8[slice.m_sliceType]) >> 8;
>
>          setLambda(x265_lambda2_tab[qp], x265_lambda_tab[qp]);
> -
> -        int qpCb = Clip3(QP_MIN, QP_MAX_MAX, qp +
> slice.m_pps->chromaQpOffset[0]);
> +        if (slice.m_sps->chromaFormatIdc == X265_CSP_I420)
> +            qpCb = Clip3(QP_MIN, QP_MAX_MAX, (int)g_chromaScale[qp +
> slice.m_pps->chromaQpOffset[0]]);
> +        else
> +            qpCb = X265_MIN(qp + slice.m_pps->chromaQpOffset[0],
> QP_MAX_SPEC);
>          int chroma_offset_idx = X265_MIN(qp - qpCb + 12,
> MAX_CHROMA_LAMBDA_OFFSET);
>          uint16_t lambdaOffset = m_psyRd ?
> x265_chroma_lambda2_offset_tab[chroma_offset_idx] : 256;
>          setCbDistortionWeight(lambdaOffset);
>
> -        int qpCr = Clip3(QP_MIN, QP_MAX_MAX, qp +
> slice.m_pps->chromaQpOffset[1]);
> +        if (slice.m_sps->chromaFormatIdc == X265_CSP_I420)
> +            qpCr = Clip3(QP_MIN, QP_MAX_MAX, (int)g_chromaScale[qp +
> slice.m_pps->chromaQpOffset[0]]);
> +        else
> +            qpCr = X265_MIN(qp + slice.m_pps->chromaQpOffset[0],
> QP_MAX_SPEC);
>          chroma_offset_idx = X265_MIN(qp - qpCr + 12,
> MAX_CHROMA_LAMBDA_OFFSET);
>          lambdaOffset = m_psyRd ?
> x265_chroma_lambda2_offset_tab[chroma_offset_idx] : 256;
>          setCrDistortionWeight(lambdaOffset);
> diff -r 511dde5ac1de -r 97f0f0e5d7ef source/encoder/sao.cpp
> --- a/source/encoder/sao.cpp    Thu Dec 04 12:43:06 2014 +0530
> +++ b/source/encoder/sao.cpp    Thu Dec 04 12:19:41 2014 +0530
> @@ -176,8 +176,11 @@
>  void SAO::startSlice(Frame* frame, Entropy& initState, int qp)
>  {
>      Slice* slice = frame->m_encData->m_slice;
> -
> -    int qpCb = Clip3(0, QP_MAX_MAX, qp + slice->m_pps->chromaQpOffset[0]);
> +    int qpCb = qp;
> +    if (m_param->internalCsp == X265_CSP_I420)
> +        qpCb = Clip3(QP_MIN, QP_MAX_MAX, (int)g_chromaScale[qp +
> slice->m_pps->chromaQpOffset[0]]);
> +    else
> +        qpCb = X265_MIN(qp + slice->m_pps->chromaQpOffset[0],
> QP_MAX_SPEC);
>      m_lumaLambda = x265_lambda2_tab[qp];
>      m_chromaLambda = x265_lambda2_tab[qpCb]; // Use Cb QP for SAO chroma
>      m_frame = frame;
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>
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