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

[Aarthi Priya Thirumalai]

We can directly use the array or the wrapper.
For high bit depth , there is no difference between the luma qp and chroma
qp. that is chroma qp = min(luma qp,51).

On Thu, Dec 4, 2014 at 4:53 PM, Deepthi Nandakumar <
deepthi at multicorewareinc.com> wrote:

> Is there an if (csp == I420) wrapper specified though? For some reason,
> deblock/quant have this.
>
> On Thu, Dec 4, 2014 at 4:50 PM, Deepthi Nandakumar <
> deepthi at multicorewareinc.com> wrote:
>
>> This looks like a Main bug where rdcost was not looking at g_chromaScale
>> at all.
>>
>>
>>
>> On Thu, Dec 4, 2014 at 4:36 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 23061220a5fe287cac893320d8ee0a782d6767c0
>>> # 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 23061220a5fe source/common/constants.cpp
>>> --- a/source/common/constants.cpp       Thu Dec 04 12:43:06 2014 +0530
>>> +++ b/source/common/constants.cpp       Thu Dec 04 12:19:41 2014 +0530
>>> @@ -289,11 +289,21 @@
>>>      {  4, -13, 22, -31, 38, -46, 54, -61, 67, -73, 78, -82, 85, -88,
>>> 90, -90, 90, -90, 88, -85, 82, -78, 73, -67, 61, -54, 46, -38, 31, -22, 13,
>>> -4 }
>>>  };
>>>
>>> +
>>> +#if HIGH_BIT_DEPTH
>>> +const uint8_t g_chromaScale[ChromaQPMappingTableSize] =
>>> +{
>>> +    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
>>> 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
>>> 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
>>> +    51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51,
>>> 51
>>> +};
>>> +
>>> +#else
>>>  const uint8_t g_chromaScale[ChromaQPMappingTableSize] =
>>>  {
>>>      0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
>>> 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 29, 30, 31, 32, 33, 33, 34, 34,
>>> 35, 35, 36, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
>>> 51,
>>>      51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51, 51
>>> -};
>>> +};
>>> +#endif
>>>
>>>  const uint8_t
>>> g_chroma422IntraAngleMappingTable[AngleMapping422TableSize] =
>>>  { 0, 1, 2, 2, 2, 2, 3, 5, 7, 8, 10, 12, 13, 15, 17, 18, 19, 20, 21, 22,
>>> 23, 23, 24, 24, 25, 25, 26, 27, 27, 28, 28, 29, 29, 30, 31, DM_CHROMA_IDX };
>>> diff -r 511dde5ac1de -r 23061220a5fe 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
>>> @@ -57,12 +57,12 @@
>>>
>>>          setLambda(x265_lambda2_tab[qp], x265_lambda_tab[qp]);
>>>
>>> -        int qpCb = Clip3(QP_MIN, QP_MAX_MAX, qp +
>>> slice.m_pps->chromaQpOffset[0]);
>>> +        int qpCb = Clip3(QP_MIN, QP_MAX_MAX, (int)g_chromaScale[qp +
>>> slice.m_pps->chromaQpOffset[0]]);
>>>          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]);
>>> +        int qpCr = Clip3(QP_MIN, QP_MAX_MAX, (int)g_chromaScale[qp +
>>> slice.m_pps->chromaQpOffset[0]]);
>>>          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 23061220a5fe 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
>>> @@ -177,7 +177,7 @@
>>>  {
>>>      Slice* slice = frame->m_encData->m_slice;
>>>
>>> -    int qpCb = Clip3(0, QP_MAX_MAX, qp +
>>> slice->m_pps->chromaQpOffset[0]);
>>> +    int qpCb = Clip3(QP_MIN, QP_MAX_MAX, (int)g_chromaScale[qp +
>>> slice->m_pps->chromaQpOffset[0]]);
>>>      m_lumaLambda = x265_lambda2_tab[qp];
>>>      m_chromaLambda = x265_lambda2_tab[qpCb]; // Use Cb QP for SAO chroma
>>>      m_frame = frame;
>>> _______________________________________________
>>> x265-devel mailing list
>>> x265-devel at videolan.org
>>> https://mailman.videolan.org/listinfo/x265-devel
>>>
>>
>>
>
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