x265 preset 工具集（基于版本2.8）

Preset:

使用方法： -p/--preset

1.ultrafast

            param->lookaheadDepth = 5;
            param->scenecutThreshold = 0; // disable lookahead
            param->maxCUSize = 32;
            param->minCUSize = 16;
            param->bframes = 3;
            param->bFrameAdaptive = 0;
            param->subpelRefine = 0;
            param->searchMethod = X265_DIA_SEARCH;
            param->bEnableEarlySkip = 1;          //为了减小CU递归深度，提前终止CU划分，默认打开
            param->bEnableSAO = 0;
            param->bEnableSignHiding = 0;        //Intra直接编码残差块，不进行DCT，默认关闭
            param->bEnableWeightedPred = 0;   //B slice中使用加权预测，默认关闭
            param->rdLevel = 2;                           //提前终止不必要的模式决策，默认关闭
            param->maxNumReferences = 1;
            param->limitReferences = 0;
            param->rc.aqStrength = 0.0;
            param->rc.aqMode = X265_AQ_NONE;
            param->rc.qgSize = 32;
            param->bEnableFastIntra = 1;      //跳过帧内DCT 

2.superfast

            param->lookaheadDepth = 10;
            param->maxCUSize = 32;
            param->bframes = 3;
            param->bFrameAdaptive = 0;
            param->subpelRefine = 1;
            param->bEnableEarlySkip = 1;
            param->bEnableWeightedPred = 0;
            param->rdLevel = 2;
            param->maxNumReferences = 1;
            param->limitReferences = 0;
            param->rc.aqStrength = 0.0;
            param->rc.aqMode = X265_AQ_NONE;
            param->rc.qgSize = 32;
            param->bEnableSAO = 0;
            param->bEnableFastIntra = 1;

3.veryfast

           param->lookaheadDepth = 15;
            param->bFrameAdaptive = 0;
            param->subpelRefine = 1;
            param->bEnableEarlySkip = 1;
            param->rdLevel = 2;
            param->maxNumReferences = 2;
            param->rc.qgSize = 32;
            param->bEnableFastIntra = 1;

4.faster

            param->lookaheadDepth = 15;
            param->bFrameAdaptive = 0;
            param->bEnableEarlySkip = 1;
            param->rdLevel = 2;
            param->maxNumReferences = 2;
            param->bEnableFastIntra = 1;

5.fast

           param->lookaheadDepth = 15;
            param->bFrameAdaptive = 0;
            param->rdLevel = 2;
            param->maxNumReferences = 3;
            param->bEnableFastIntra = 1;

6.medium

           /* defaults */

7.slow

           param->bEnableRectInter = 1;
            param->lookaheadDepth = 25;
            param->rdLevel = 4;
            param->rdoqLevel = 2;
            param->psyRdoq = 1.0;
            param->subpelRefine = 3;
            param->maxNumMergeCand = 3;
            param->searchMethod = X265_STAR_SEARCH;
            param->maxNumReferences = 4;
            param->limitModes = 1;
            param->lookaheadSlices = 4; // limit parallelism as already enough work exists

8.slower

           param->bEnableWeightedBiPred = 1;
            param->bEnableAMP = 1;
            param->bEnableRectInter = 1;
            param->lookaheadDepth = 30;
            param->bframes = 8;
            param->tuQTMaxInterDepth = 2;
            param->tuQTMaxIntraDepth = 2;
            param->rdLevel = 6;
            param->rdoqLevel = 2;
            param->psyRdoq = 1.0;
            param->subpelRefine = 3;
            param->maxNumMergeCand = 3;
            param->searchMethod = X265_STAR_SEARCH;
            param->maxNumReferences = 4;
            param->limitReferences = 2;
            param->limitModes = 1;
            param->bIntraInBFrames = 1;
            param->lookaheadSlices = 4; // limit parallelism as already enough work exists
            param->limitTU = 4;

9.veryslow

           param->bEnableWeightedBiPred = 1;
            param->bEnableAMP = 1;
            param->bEnableRectInter = 1;
            param->lookaheadDepth = 40;
            param->bframes = 8;
            param->tuQTMaxInterDepth = 3;
            param->tuQTMaxIntraDepth = 3;
            param->rdLevel = 6;
            param->rdoqLevel = 2;
            param->psyRdoq = 1.0;
            param->subpelRefine = 4;
            param->maxNumMergeCand = 4;
            param->searchMethod = X265_STAR_SEARCH;
            param->maxNumReferences = 5;
            param->limitReferences = 1;
            param->limitModes = 1;
            param->bIntraInBFrames = 1;
            param->lookaheadSlices = 0; // disabled for best quality
            param->limitTU = 4;

10.placebo

           param->bEnableWeightedBiPred = 1;
            param->bEnableAMP = 1;
            param->bEnableRectInter = 1;
            param->lookaheadDepth = 60;
            param->searchRange = 92;
            param->bframes = 8;
            param->tuQTMaxInterDepth = 4;
            param->tuQTMaxIntraDepth = 4;
            param->rdLevel = 6;
            param->rdoqLevel = 2;
            param->psyRdoq = 1.0;
            param->subpelRefine = 5;
            param->maxNumMergeCand = 5;
            param->searchMethod = X265_STAR_SEARCH;
            param->bEnableTransformSkip = 1;
            param->bEnableRecursionSkip = 0;
            param->maxNumReferences = 5;
            param->limitReferences = 0;
            param->bIntraInBFrames = 1;
            param->lookaheadSlices = 0; // disabled for best quality
            // TODO: optimized esa

Tune: 建议使用 –tune，否则结果不能用于比较

使用方法： -t/--tune

1.psnr

            param->rc.aqStrength = 0.0;
            param->psyRd = 0.0;
            param->psyRdoq = 0.0;

2.ssim

           param->rc.aqMode = X265_AQ_AUTO_VARIANCE;
            param->psyRd = 0.0;
            param->psyRdoq = 0.0;

3.fastdecode or fast-decode

           param->bEnableLoopFilter = 0;
            param->bEnableSAO = 0;
            param->bEnableWeightedPred = 0;
            param->bEnableWeightedBiPred = 0;
            param->bIntraInBFrames = 0;

4.zerolatency or zero-latency

            param->bFrameAdaptive = 0;
            param->bframes = 0;
            param->lookaheadDepth = 0;
            param->scenecutThreshold = 0;
            param->rc.cuTree = 0;
            param->frameNumThreads = 1;

5.grain

            param->rc.ipFactor = 1.1;
            param->rc.pbFactor = 1.0;
            param->rc.cuTree = 0;
            param->rc.aqMode = 0;
            param->rc.qpStep = 1;
            param->rc.bEnableGrain = 1;
            param->bEnableRecursionSkip = 0;
            param->psyRd = 4.0;
            param->psyRdoq = 10.0;
            param->bEnableSAO = 0;
            param->rc.bEnableConstVbv = 1;