/***************************************************************************** * Copyright (C) 2014 x265 project * * Authors: Steve Borho * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA. * * This program is also available under a commercial proprietary license. * For more information, contact us at license @ x265.com. *****************************************************************************/ #include "common.h" #include "primitives.h" #include "quant.h" #include "frame.h" #include "entropy.h" #include "TLibCommon/TComDataCU.h" #include "TLibCommon/TComYuv.h" #include "TLibCommon/ContextTables.h" using namespace x265; #define SIGN(x,y) ((x^(y >> 31))-(y >> 31)) namespace { struct coeffGroupRDStats { int nnzBeforePos0; /* indicates coeff other than pos 0 are coded */ int64_t codedLevelAndDist; /* distortion and level cost of coded coefficients */ int64_t uncodedDist; /* uncoded distortion cost of coded coefficients */ int64_t sigCost; /* cost of signaling significant coeff bitmap */ int64_t sigCost0; /* cost of signaling sig coeff bit of coeff 0 */ }; inline int fastMin(int x, int y) { return y + ((x - y) & ((x - y) >> (sizeof(int) * CHAR_BIT - 1))); // min(x, y) } inline int getICRate(uint32_t absLevel, int32_t diffLevel, const int *greaterOneBits, const int *levelAbsBits, uint32_t absGoRice, uint32_t c1c2Idx) { X265_CHECK(c1c2Idx <= 3, "c1c2Idx check failure\n"); X265_CHECK(absGoRice <= 4, "absGoRice check failure\n"); if (!absLevel) { X265_CHECK(diffLevel < 0, "diffLevel check failure\n"); return 0; } int rate = 0; if (diffLevel < 0) { X265_CHECK(absLevel <= 2, "absLevel check failure\n"); rate += greaterOneBits[(absLevel == 2)]; if (absLevel == 2) rate += levelAbsBits[0]; } else { uint32_t symbol = diffLevel; const uint32_t maxVlc = g_goRiceRange[absGoRice]; bool expGolomb = (symbol > maxVlc); if (expGolomb) { absLevel = symbol - maxVlc; // NOTE: mapping to x86 hardware instruction BSR unsigned long size; CLZ32(size, absLevel); int egs = size * 2 + 1; rate += egs << 15; // NOTE: in here, expGolomb=true means (symbol >= maxVlc + 1) X265_CHECK(fastMin(symbol, (maxVlc + 1)) == (int)maxVlc + 1, "min check failure\n"); symbol = maxVlc + 1; } uint32_t prefLen = (symbol >> absGoRice) + 1; uint32_t numBins = fastMin(prefLen + absGoRice, 8 /* g_goRicePrefixLen[absGoRice] + absGoRice */); rate += numBins << 15; if (c1c2Idx & 1) rate += greaterOneBits[1]; if (c1c2Idx == 3) rate += levelAbsBits[1]; } return rate; } /* Calculates the cost for specific absolute transform level */ inline uint32_t getICRateCost(uint32_t absLevel, int32_t diffLevel, const int *greaterOneBits, const int *levelAbsBits, uint32_t absGoRice, uint32_t c1c2Idx) { X265_CHECK(absLevel, "absLevel should not be zero\n"); if (diffLevel < 0) { X265_CHECK((absLevel == 1) || (absLevel == 2), "absLevel range check failure\n"); uint32_t rate = greaterOneBits[(absLevel == 2)]; if (absLevel == 2) rate += levelAbsBits[0]; return rate; } else { uint32_t rate; uint32_t symbol = diffLevel; if ((symbol >> absGoRice) < COEF_REMAIN_BIN_REDUCTION) { uint32_t length = symbol >> absGoRice; rate = (length + 1 + absGoRice) << 15; } else { uint32_t length = 0; symbol = (symbol >> absGoRice) - COEF_REMAIN_BIN_REDUCTION; if (symbol) { unsigned long idx; CLZ32(idx, symbol + 1); length = idx; } rate = (COEF_REMAIN_BIN_REDUCTION + length + absGoRice + 1 + length) << 15; } if (c1c2Idx & 1) rate += greaterOneBits[1]; if (c1c2Idx == 3) rate += levelAbsBits[1]; return rate; } } } Quant::Quant() { m_resiDctCoeff = NULL; m_fencDctCoeff = NULL; m_fencShortBuf = NULL; } bool Quant::init(bool useRDOQ, double psyScale, const ScalingList& scalingList) { m_useRDOQ = useRDOQ; m_psyRdoqScale = (int64_t)(psyScale * 256.0); m_scalingList = &scalingList; m_resiDctCoeff = X265_MALLOC(int32_t, MAX_TR_SIZE * MAX_TR_SIZE * 2); m_fencDctCoeff = m_resiDctCoeff + (MAX_TR_SIZE * MAX_TR_SIZE); m_fencShortBuf = X265_MALLOC(int16_t, MAX_TR_SIZE * MAX_TR_SIZE); return m_resiDctCoeff && m_fencShortBuf; } Quant::~Quant() { X265_FREE(m_resiDctCoeff); X265_FREE(m_fencShortBuf); } void Quant::setQPforQuant(TComDataCU* cu) { int qpy = cu->getQP(0); int chFmt = cu->getChromaFormat(); m_qpParam[TEXT_LUMA].setQpParam(qpy + QP_BD_OFFSET); setChromaQP(qpy + cu->m_slice->m_pps->chromaCbQpOffset, TEXT_CHROMA_U, chFmt); setChromaQP(qpy + cu->m_slice->m_pps->chromaCrQpOffset, TEXT_CHROMA_V, chFmt); } void Quant::setChromaQP(int qpin, TextType ttype, int chFmt) { int qp = Clip3(-QP_BD_OFFSET, 57, qpin); if (qp >= 30) { if (chFmt == X265_CSP_I420) qp = g_chromaScale[qp]; else qp = X265_MIN(qp, 51); } m_qpParam[ttype].setQpParam(qp + QP_BD_OFFSET); } /* To minimize the distortion only. No rate is considered */ uint32_t Quant::signBitHidingHDQ(int16_t* coeff, int32_t* deltaU, uint32_t numSig, const TUEntropyCodingParameters &codeParams) { const uint32_t log2TrSizeCG = codeParams.log2TrSizeCG; const uint16_t *scan = codeParams.scan; bool lastCG = true; for (int cg = (1 << log2TrSizeCG * 2) - 1; cg >= 0; cg--) { int cgStartPos = cg << LOG2_SCAN_SET_SIZE; int n; for (n = SCAN_SET_SIZE - 1; n >= 0; --n) if (coeff[scan[n + cgStartPos]]) break; if (n < 0) continue; int lastNZPosInCG = n; for (n = 0;; n++) if (coeff[scan[n + cgStartPos]]) break; int firstNZPosInCG = n; if (lastNZPosInCG - firstNZPosInCG >= SBH_THRESHOLD) { uint32_t signbit = coeff[scan[cgStartPos + firstNZPosInCG]] > 0 ? 0 : 1; uint32_t absSum = 0; for (n = firstNZPosInCG; n <= lastNZPosInCG; n++) absSum += coeff[scan[n + cgStartPos]]; if (signbit != (absSum & 0x1)) // compare signbit with sum_parity { int minCostInc = MAX_INT, minPos = -1, curCost = MAX_INT; int16_t finalChange = 0, curChange = 0; for (n = (lastCG ? lastNZPosInCG : SCAN_SET_SIZE - 1); n >= 0; --n) { uint32_t blkPos = scan[n + cgStartPos]; if (coeff[blkPos]) { if (deltaU[blkPos] > 0) { curCost = -deltaU[blkPos]; curChange = 1; } else { if (n == firstNZPosInCG && abs(coeff[blkPos]) == 1) curCost = MAX_INT; else { curCost = deltaU[blkPos]; curChange = -1; } } } else { if (n < firstNZPosInCG) { uint32_t thisSignBit = m_resiDctCoeff[blkPos] >= 0 ? 0 : 1; if (thisSignBit != signbit) curCost = MAX_INT; else { curCost = -deltaU[blkPos]; curChange = 1; } } else { curCost = -deltaU[blkPos]; curChange = 1; } } if (curCost < minCostInc) { minCostInc = curCost; finalChange = curChange; minPos = blkPos; } } /* do not allow change to violate coeff clamp */ if (coeff[minPos] == 32767 || coeff[minPos] == -32768) finalChange = -1; if (!coeff[minPos]) numSig++; else if (finalChange == -1 && abs(coeff[minPos]) == 1) numSig--; if (m_resiDctCoeff[minPos] >= 0) coeff[minPos] += finalChange; else coeff[minPos] -= finalChange; } } lastCG = false; } return numSig; } uint32_t Quant::transformNxN(TComDataCU* cu, pixel* fenc, uint32_t fencStride, int16_t* residual, uint32_t stride, coeff_t* coeff, uint32_t log2TrSize, TextType ttype, uint32_t absPartIdx, bool useTransformSkip) { if (cu->getCUTransquantBypass(absPartIdx)) { X265_CHECK(log2TrSize >= 2 && log2TrSize <= 5, "Block size mistake!\n"); return primitives.copy_cnt[log2TrSize - 2](coeff, residual, stride); } bool isLuma = ttype == TEXT_LUMA; bool usePsy = m_psyRdoqScale && isLuma && !useTransformSkip; bool isIntra = cu->getPredictionMode(absPartIdx) == MODE_INTRA; int transformShift = MAX_TR_DYNAMIC_RANGE - X265_DEPTH - log2TrSize; // Represents scaling through forward transform int trSize = 1 << log2TrSize; X265_CHECK((cu->m_slice->m_sps->quadtreeTULog2MaxSize >= log2TrSize), "transform size too large\n"); if (useTransformSkip) { #if X265_DEPTH <= 10 primitives.cvt16to32_shl(m_resiDctCoeff, residual, stride, transformShift, trSize); #else if (transformShift >= 0) primitives.cvt16to32_shl(m_resiDctCoeff, residual, stride, transformShift, trSize); else { int shift = -transformShift; int offset = (1 << (shift - 1)); primitives.cvt16to32_shr[log2TrSize - 2](m_resiDctCoeff, residual, stride, shift, offset); } #endif } else { const uint32_t sizeIdx = log2TrSize - 2; int useDST = !sizeIdx && isLuma && isIntra; int index = DCT_4x4 + sizeIdx - useDST; primitives.dct[index](residual, m_resiDctCoeff, stride); /* NOTE: if RDOQ is disabled globally, psy-rdoq is also disabled, so * there is no risk of performing this DCT unnecessarily */ if (usePsy) { /* perform DCT on source pixels for psy-rdoq */ primitives.square_copy_ps[sizeIdx](m_fencShortBuf, trSize, fenc, fencStride); primitives.dct[index](m_fencShortBuf, m_fencDctCoeff, trSize); } if (m_nr && !isIntra) { /* denoise is not applied to intra residual, so DST can be ignored */ int cat = sizeIdx + 4 * !isLuma; int numCoeff = 1 << log2TrSize * 2; primitives.denoiseDct(m_resiDctCoeff, m_nr->residualSum[cat], m_nr->offsetDenoise[cat], numCoeff); m_nr->count[cat]++; } } if (m_useRDOQ) return rdoQuant(cu, coeff, log2TrSize, ttype, absPartIdx, usePsy); else { int deltaU[32 * 32]; int scalingListType = ttype + (isLuma ? 3 : 0); int rem = m_qpParam[ttype].rem; int per = m_qpParam[ttype].per; int32_t *quantCoeff = m_scalingList->m_quantCoef[log2TrSize - 2][scalingListType][rem]; int qbits = QUANT_SHIFT + per + transformShift; int add = (cu->m_slice->m_sliceType == I_SLICE ? 171 : 85) << (qbits - 9); int numCoeff = 1 << log2TrSize * 2; uint32_t numSig = primitives.quant(m_resiDctCoeff, quantCoeff, deltaU, coeff, qbits, add, numCoeff); if (numSig >= 2 && cu->m_slice->m_pps->bSignHideEnabled) { TUEntropyCodingParameters codeParams; cu->getTUEntropyCodingParameters(codeParams, absPartIdx, log2TrSize, isLuma); return signBitHidingHDQ(coeff, deltaU, numSig, codeParams); } else return numSig; } } void Quant::invtransformNxN(bool transQuantBypass, int16_t* residual, uint32_t stride, coeff_t* coeff, uint32_t log2TrSize, TextType ttype, bool bIntra, bool useTransformSkip, uint32_t numSig) { if (transQuantBypass) { primitives.copy_shl[log2TrSize - 2](residual, coeff, stride, 0); return; } // Values need to pass as input parameter in dequant int rem = m_qpParam[ttype].rem; int per = m_qpParam[ttype].per; int transformShift = MAX_TR_DYNAMIC_RANGE - X265_DEPTH - log2TrSize; int shift = QUANT_IQUANT_SHIFT - QUANT_SHIFT - transformShift; int numCoeff = 1 << log2TrSize * 2; if (m_scalingList->m_bEnabled) { int scalingListType = (bIntra ? 0 : 3) + ttype; int32_t *dequantCoef = m_scalingList->m_dequantCoef[log2TrSize - 2][scalingListType][rem]; primitives.dequant_scaling(coeff, dequantCoef, m_resiDctCoeff, numCoeff, per, shift); } else { int scale = m_scalingList->s_invQuantScales[rem] << per; primitives.dequant_normal(coeff, m_resiDctCoeff, numCoeff, scale, shift); } if (useTransformSkip) { int trSize = 1 << log2TrSize; #if X265_DEPTH <= 10 primitives.cvt32to16_shr(residual, m_resiDctCoeff, stride, transformShift, trSize); #else if (transformShift > 0) primitives.cvt32to16_shr(residual, m_resiDctCoeff, stride, transformShift, trSize); else primitives.cvt32to16_shl[log2TrSize - 2](residual, m_resiDctCoeff, stride, -transformShift); #endif } else { const uint32_t sizeIdx = log2TrSize - 2; int useDST = !sizeIdx && ttype == TEXT_LUMA && bIntra; X265_CHECK((int)numSig == primitives.count_nonzero(coeff, 1 << log2TrSize * 2), "numSig differ\n"); // DC only if (numSig == 1 && coeff[0] != 0 && !useDST) { const int shift_1st = 7; const int add_1st = 1 << (shift_1st - 1); const int shift_2nd = 12 - (X265_DEPTH - 8); const int add_2nd = 1 << (shift_2nd - 1); int dc_val = (((m_resiDctCoeff[0] * 64 + add_1st) >> shift_1st) * 64 + add_2nd) >> shift_2nd; primitives.blockfill_s[sizeIdx](residual, stride, (int16_t)dc_val); return; } primitives.idct[IDCT_4x4 + sizeIdx - useDST](m_resiDctCoeff, residual, stride); } } /* Rate distortion optimized quantization for entropy coding engines using * probability models like CABAC */ uint32_t Quant::rdoQuant(TComDataCU* cu, int16_t* dstCoeff, uint32_t log2TrSize, TextType ttype, uint32_t absPartIdx, bool usePsy) { int transformShift = MAX_TR_DYNAMIC_RANGE - X265_DEPTH - log2TrSize; /* Represents scaling through forward transform */ int scalingListType = (cu->isIntra(absPartIdx) ? 0 : 3) + ttype; X265_CHECK(scalingListType < 6, "scaling list type out of range\n"); int rem = m_qpParam[ttype].rem; int per = m_qpParam[ttype].per; int qbits = QUANT_SHIFT + per + transformShift; /* Right shift of non-RDOQ quantizer level = (coeff*Q + offset)>>q_bits */ int add = (1 << (qbits - 1)); int32_t *qCoef = m_scalingList->m_quantCoef[log2TrSize - 2][scalingListType][rem]; int numCoeff = 1 << log2TrSize * 2; uint32_t numSig = primitives.nquant(m_resiDctCoeff, qCoef, dstCoeff, qbits, add, numCoeff); X265_CHECK((int)numSig == primitives.count_nonzero(dstCoeff, 1 << log2TrSize * 2), "numSig differ\n"); if (!numSig) return 0; uint32_t trSize = 1 << log2TrSize; int64_t lambda2 = m_qpParam[ttype].lambda2; int64_t psyScale = (m_psyRdoqScale * m_qpParam[ttype].lambda); /* unquant constants for measuring distortion. Scaling list quant coefficients have a (1 << 4) * scale applied that must be removed during unquant. Note that in real dequant there is clipping * at several stages. We skip the clipping for simplicity when measuring RD cost */ int32_t *unquantScale = m_scalingList->m_dequantCoef[log2TrSize - 2][scalingListType][rem]; int unquantShift = QUANT_IQUANT_SHIFT - QUANT_SHIFT - transformShift + (m_scalingList->m_bEnabled ? 4 : 0); int unquantRound = (unquantShift > per) ? 1 << (unquantShift - per - 1) : 0; int scaleBits = SCALE_BITS - 2 * transformShift; #define UNQUANT(lvl) (((lvl) * (unquantScale[blkPos] << per) + unquantRound) >> unquantShift) #define SIGCOST(bits) ((lambda2 * (bits)) >> 8) #define RDCOST(d, bits) ((((int64_t)d * d) << scaleBits) + SIGCOST(bits)) #define PSYVALUE(rec) ((psyScale * (rec)) >> (16 - scaleBits)) int64_t costCoeff[32 * 32]; /* d*d + lambda * bits */ int64_t costUncoded[32 * 32]; /* d*d + lambda * 0 */ int64_t costSig[32 * 32]; /* lambda * bits */ int rateIncUp[32 * 32]; /* signal overhead of increasing level */ int rateIncDown[32 * 32]; /* signal overhead of decreasing level */ int sigRateDelta[32 * 32]; /* signal difference between zero and non-zero */ int64_t costCoeffGroupSig[MLS_GRP_NUM]; /* lambda * bits of group coding cost */ uint64_t sigCoeffGroupFlag64 = 0; uint32_t ctxSet = 0; int c1 = 1; int c2 = 0; uint32_t goRiceParam = 0; uint32_t c1Idx = 0; uint32_t c2Idx = 0; int cgLastScanPos = -1; int lastScanPos = -1; const uint32_t cgSize = (1 << MLS_CG_SIZE); /* 4x4 num coef = 16 */ bool bIsLuma = ttype == TEXT_LUMA; /* total rate distortion cost of transform block, as CBF=0 */ int64_t totalUncodedCost = 0; /* Total rate distortion cost of this transform block, counting te distortion of uncoded blocks, * the distortion and signal cost of coded blocks, and the coding cost of significant * coefficient and coefficient group bitmaps */ int64_t totalRdCost = 0; TUEntropyCodingParameters codeParams; cu->getTUEntropyCodingParameters(codeParams, absPartIdx, log2TrSize, bIsLuma); const uint32_t cgNum = 1 << codeParams.log2TrSizeCG * 2; /* TODO: update bit estimates if dirty */ EstBitsSbac& estBitsSbac = m_entropyCoder->m_estBitsSbac; uint32_t scanPos; coeffGroupRDStats cgRdStats; /* iterate over coding groups in reverse scan order */ for (int cgScanPos = cgNum - 1; cgScanPos >= 0; cgScanPos--) { const uint32_t cgBlkPos = codeParams.scanCG[cgScanPos]; const uint32_t cgPosY = cgBlkPos >> codeParams.log2TrSizeCG; const uint32_t cgPosX = cgBlkPos - (cgPosY << codeParams.log2TrSizeCG); const uint64_t cgBlkPosMask = ((uint64_t)1 << cgBlkPos); memset(&cgRdStats, 0, sizeof(coeffGroupRDStats)); const int patternSigCtx = calcPatternSigCtx(sigCoeffGroupFlag64, cgPosX, cgPosY, codeParams.log2TrSizeCG); /* iterate over coefficients in each group in reverse scan order */ for (int scanPosinCG = cgSize - 1; scanPosinCG >= 0; scanPosinCG--) { scanPos = (cgScanPos << MLS_CG_SIZE) + scanPosinCG; uint32_t blkPos = codeParams.scan[scanPos]; uint16_t maxAbsLevel = (int16_t)abs(dstCoeff[blkPos]); /* abs(quantized coeff) */ int signCoef = m_resiDctCoeff[blkPos]; /* pre-quantization DCT coeff */ int predictedCoef = m_fencDctCoeff[blkPos] - signCoef; /* predicted DCT = source DCT - residual DCT*/ /* RDOQ measures distortion as the squared difference between the unquantized coded level * and the original DCT coefficient. The result is shifted scaleBits to account for the * FIX15 nature of the CABAC cost tables minus the forward transform scale */ /* cost of not coding this coefficient (all distortion, no signal bits) */ costUncoded[scanPos] = (int64_t)(signCoef * signCoef) << scaleBits; if (usePsy && blkPos) /* when no residual coefficient is coded, predicted coef == recon coef */ costUncoded[scanPos] -= PSYVALUE(predictedCoef); totalUncodedCost += costUncoded[scanPos]; if (maxAbsLevel && lastScanPos < 0) { /* remember the first non-zero coef found in this reverse scan as the last pos */ lastScanPos = scanPos; ctxSet = (scanPos < SCAN_SET_SIZE || !bIsLuma) ? 0 : 2; cgLastScanPos = cgScanPos; } if (lastScanPos < 0) { /* coefficients after lastNZ have no distortion signal cost */ costCoeff[scanPos] = 0; costSig[scanPos] = 0; /* No non-zero coefficient yet found, but this does not mean * there is no uncoded-cost for this coefficient. Pre- * quantization the coefficient may have been non-zero */ totalRdCost += costUncoded[scanPos]; } else { const uint32_t c1c2Idx = ((c1Idx - 8) >> (sizeof(int) * CHAR_BIT - 1)) + (((-(int)c2Idx) >> (sizeof(int) * CHAR_BIT - 1)) + 1) * 2; const uint32_t baseLevel = ((uint32_t)0xD9 >> (c1c2Idx * 2)) & 3; // {1, 2, 1, 3} X265_CHECK(!!((int)c1Idx < C1FLAG_NUMBER) == (int)((c1Idx - 8) >> (sizeof(int) * CHAR_BIT - 1)), "scan validation 1\n"); X265_CHECK(!!(c2Idx == 0) == ((-(int)c2Idx) >> (sizeof(int) * CHAR_BIT - 1)) + 1, "scan validation 2\n"); X265_CHECK((int)baseLevel == ((c1Idx < C1FLAG_NUMBER) ? (2 + (c2Idx == 0)) : 1), "scan validation 3\n"); // coefficient level estimation const uint32_t oneCtx = 4 * ctxSet + c1; const uint32_t absCtx = ctxSet + c2; const int *greaterOneBits = estBitsSbac.greaterOneBits[oneCtx]; const int *levelAbsBits = estBitsSbac.levelAbsBits[absCtx]; uint16_t level = 0; uint32_t sigCoefBits = 0; costCoeff[scanPos] = MAX_INT64; if ((int)scanPos == lastScanPos) sigRateDelta[blkPos] = 0; else { const uint32_t ctxSig = getSigCtxInc(patternSigCtx, log2TrSize, trSize, blkPos, bIsLuma, codeParams.firstSignificanceMapContext); if (maxAbsLevel < 3) { /* set default costs to uncoded costs */ costSig[scanPos] = SIGCOST(estBitsSbac.significantBits[ctxSig][0]); costCoeff[scanPos] = costUncoded[scanPos] + costSig[scanPos]; } sigRateDelta[blkPos] = estBitsSbac.significantBits[ctxSig][1] - estBitsSbac.significantBits[ctxSig][0]; sigCoefBits = estBitsSbac.significantBits[ctxSig][1]; } if (maxAbsLevel) { uint16_t minAbsLevel = X265_MAX(maxAbsLevel - 1, 1); for (uint16_t lvl = maxAbsLevel; lvl >= minAbsLevel; lvl--) { uint32_t levelBits = getICRateCost(lvl, lvl - baseLevel, greaterOneBits, levelAbsBits, goRiceParam, c1c2Idx) + IEP_RATE; int unquantAbsLevel = UNQUANT(lvl); int d = abs(signCoef) - unquantAbsLevel; int64_t curCost = RDCOST(d, sigCoefBits + levelBits); /* Psy RDOQ: bias in favor of higher AC coefficients in the reconstructed frame */ if (usePsy && blkPos) { int reconCoef = abs(unquantAbsLevel + SIGN(predictedCoef, signCoef)); curCost -= PSYVALUE(reconCoef); } if (curCost < costCoeff[scanPos]) { level = lvl; costCoeff[scanPos] = curCost; costSig[scanPos] = SIGCOST(sigCoefBits); } } } dstCoeff[blkPos] = level; totalRdCost += costCoeff[scanPos]; /* record costs for sign-hiding performed at the end */ if (level) { int rateNow = getICRate(level, level - baseLevel, greaterOneBits, levelAbsBits, goRiceParam, c1c2Idx); rateIncUp[blkPos] = getICRate(level + 1, level + 1 - baseLevel, greaterOneBits, levelAbsBits, goRiceParam, c1c2Idx) - rateNow; rateIncDown[blkPos] = getICRate(level - 1, level - 1 - baseLevel, greaterOneBits, levelAbsBits, goRiceParam, c1c2Idx) - rateNow; } else { rateIncUp[blkPos] = greaterOneBits[0]; rateIncDown[blkPos] = 0; } /* Update CABAC estimation state */ if (level >= baseLevel && goRiceParam < 4 && level > (3U << goRiceParam)) goRiceParam++; c1Idx -= (-(int32_t)level) >> 31; /* update bin model */ if (level > 1) { c1 = 0; c2 += (uint32_t)(c2 - 2) >> 31; c2Idx++; } else if ((c1 < 3) && (c1 > 0) && level) c1++; /* context set update */ if (!(scanPos % SCAN_SET_SIZE) && scanPos) { c2 = 0; goRiceParam = 0; c1Idx = 0; c2Idx = 0; ctxSet = (scanPos == SCAN_SET_SIZE || !bIsLuma) ? 0 : 2; X265_CHECK(c1 >= 0, "c1 is negative\n"); ctxSet -= ((int32_t)(c1 - 1) >> 31); c1 = 1; } } cgRdStats.sigCost += costSig[scanPos]; if (!scanPosinCG) cgRdStats.sigCost0 = costSig[scanPos]; if (dstCoeff[blkPos]) { sigCoeffGroupFlag64 |= cgBlkPosMask; cgRdStats.codedLevelAndDist += costCoeff[scanPos] - costSig[scanPos]; cgRdStats.uncodedDist += costUncoded[scanPos]; cgRdStats.nnzBeforePos0 += scanPosinCG; } } /* end for (scanPosinCG) */ costCoeffGroupSig[cgScanPos] = 0; if (cgLastScanPos < 0) { /* nothing to do at this point */ } else if (!cgScanPos || cgScanPos == cgLastScanPos) { /* coeff group 0 is implied to be present, no signal cost */ /* coeff group with last NZ is implied to be present, handled below */ } else if (sigCoeffGroupFlag64 & cgBlkPosMask) { if (!cgRdStats.nnzBeforePos0) { /* if only coeff 0 in this CG is coded, its significant coeff bit is implied */ totalRdCost -= cgRdStats.sigCost0; cgRdStats.sigCost -= cgRdStats.sigCost0; } /* there are coded coefficients in this group, but now we include the signaling cost * of the significant coefficient group flag and evaluate whether the RD cost of the * coded group is more than the RD cost of the uncoded group */ uint32_t sigCtx = getSigCoeffGroupCtxInc(sigCoeffGroupFlag64, cgPosX, cgPosY, codeParams.log2TrSizeCG); int64_t costZeroCG = totalRdCost + SIGCOST(estBitsSbac.significantCoeffGroupBits[sigCtx][0]); costZeroCG += cgRdStats.uncodedDist; /* add distortion for resetting non-zero levels to zero levels */ costZeroCG -= cgRdStats.codedLevelAndDist; /* remove distortion and level cost of coded coefficients */ costZeroCG -= cgRdStats.sigCost; /* remove signaling cost of significant coeff bitmap */ costCoeffGroupSig[cgScanPos] = SIGCOST(estBitsSbac.significantCoeffGroupBits[sigCtx][1]); totalRdCost += costCoeffGroupSig[cgScanPos]; /* add the cost of 1 bit in significant CG bitmap */ if (costZeroCG < totalRdCost) { sigCoeffGroupFlag64 &= ~cgBlkPosMask; totalRdCost = costZeroCG; costCoeffGroupSig[cgScanPos] = SIGCOST(estBitsSbac.significantCoeffGroupBits[sigCtx][0]); /* reset all coeffs to 0. UNCODE THIS COEFF GROUP! */ for (int scanPosinCG = cgSize - 1; scanPosinCG >= 0; scanPosinCG--) { scanPos = cgScanPos * cgSize + scanPosinCG; uint32_t blkPos = codeParams.scan[scanPos]; if (dstCoeff[blkPos]) { costCoeff[scanPos] = costUncoded[scanPos]; costSig[scanPos] = 0; } dstCoeff[blkPos] = 0; } } } else { /* there were no coded coefficients in this coefficient group */ uint32_t ctxSig = getSigCoeffGroupCtxInc(sigCoeffGroupFlag64, cgPosX, cgPosY, codeParams.log2TrSizeCG); costCoeffGroupSig[cgScanPos] = SIGCOST(estBitsSbac.significantCoeffGroupBits[ctxSig][0]); totalRdCost += costCoeffGroupSig[cgScanPos]; /* add cost of 0 bit in significant CG bitmap */ totalRdCost -= cgRdStats.sigCost; /* remove cost of significant coefficient bitmap */ } } /* end for (cgScanPos) */ X265_CHECK(lastScanPos >= 0, "numSig non zero, but no coded CG\n"); /* calculate RD cost of uncoded block CBF=0, and add cost of CBF=1 to total */ int64_t bestCost; if (!cu->isIntra(absPartIdx) && bIsLuma && !cu->getTransformIdx(absPartIdx)) { bestCost = totalUncodedCost + SIGCOST(estBitsSbac.blockRootCbpBits[0]); totalRdCost += SIGCOST(estBitsSbac.blockRootCbpBits[1]); } else { int ctx = ctxCbf[ttype][cu->getTransformIdx(absPartIdx)]; bestCost = totalUncodedCost + SIGCOST(estBitsSbac.blockCbpBits[ctx][0]); totalRdCost += SIGCOST(estBitsSbac.blockCbpBits[ctx][1]); } /* This loop starts with the last non-zero found in the first loop and then refines this last * non-zero by measuring the true RD cost of the last NZ at this position, and then the RD costs * at all previous coefficients until a coefficient greater than 1 is encountered or we run out * of coefficients to evaluate. This will factor in the cost of coding empty groups and empty * coeff prior to the last NZ. The base best cost is the RD cost of CBF=0 */ int bestLastIdx = 0; bool foundLast = false; for (int cgScanPos = cgLastScanPos; cgScanPos >= 0 && !foundLast; cgScanPos--) { if (!cgScanPos || cgScanPos == cgLastScanPos) { /* the presence of these coefficient groups are inferred, they have no bit in * sigCoeffGroupFlag64 and no saved costCoeffGroupSig[] cost */ } else if (sigCoeffGroupFlag64 & (1ULL << codeParams.scanCG[cgScanPos])) { /* remove cost of significant coeff group flag, the group's presence would be inferred * from lastNZ if it were present in this group */ totalRdCost -= costCoeffGroupSig[cgScanPos]; } else { /* remove cost of signaling this empty group as not present */ totalRdCost -= costCoeffGroupSig[cgScanPos]; continue; } for (int scanPosinCG = cgSize - 1; scanPosinCG >= 0; scanPosinCG--) { scanPos = cgScanPos * cgSize + scanPosinCG; if ((int)scanPos > lastScanPos) continue; /* if the coefficient was coded, measure the RD cost of it as the last non-zero and then * continue as if it were uncoded. If the coefficient was already uncoded, remove the * cost of signaling it as not-significant */ uint32_t blkPos = codeParams.scan[scanPos]; if (dstCoeff[blkPos]) { /* Swap the cost of signaling its significant coeff bit with the cost of * signaling its lastNZ pos */ uint32_t posY = blkPos >> log2TrSize; uint32_t posX = blkPos - (posY << log2TrSize); uint32_t bitsLastNZ = codeParams.scanType == SCAN_VER ? getRateLast(posY, posX) : getRateLast(posX, posY); int64_t costAsLast = totalRdCost - costSig[scanPos] + SIGCOST(bitsLastNZ); if (costAsLast < bestCost) { bestLastIdx = scanPos + 1; bestCost = costAsLast; } if (dstCoeff[blkPos] > 1) { foundLast = true; break; } totalRdCost -= costCoeff[scanPos]; totalRdCost += costUncoded[scanPos]; } else totalRdCost -= costSig[scanPos]; } } /* recount non-zero coefficients and re-apply sign of DCT coef */ numSig = 0; for (int pos = 0; pos < bestLastIdx; pos++) { int blkPos = codeParams.scan[pos]; int level = dstCoeff[blkPos]; numSig += (level != 0); uint32_t mask = (int32_t)m_resiDctCoeff[blkPos] >> 31; dstCoeff[blkPos] = (int16_t)((level ^ mask) - mask); } /* clean uncoded coefficients */ for (int pos = bestLastIdx; pos <= lastScanPos; pos++) dstCoeff[codeParams.scan[pos]] = 0; /* rate-distortion based sign-hiding */ if (cu->m_slice->m_pps->bSignHideEnabled && numSig >= 2) { int lastCG = true; for (int subSet = cgLastScanPos; subSet >= 0; subSet--) { int subPos = subSet << LOG2_SCAN_SET_SIZE; int n; /* measure distance between first and last non-zero coef in this * coding group */ for (n = SCAN_SET_SIZE - 1; n >= 0; --n) if (dstCoeff[codeParams.scan[n + subPos]]) break; if (n < 0) continue; int lastNZPosInCG = n; for (n = 0;; n++) if (dstCoeff[codeParams.scan[n + subPos]]) break; int firstNZPosInCG = n; if (lastNZPosInCG - firstNZPosInCG >= SBH_THRESHOLD) { uint32_t signbit = (dstCoeff[codeParams.scan[subPos + firstNZPosInCG]] > 0 ? 0 : 1); int absSum = 0; for (n = firstNZPosInCG; n <= lastNZPosInCG; n++) absSum += dstCoeff[codeParams.scan[n + subPos]]; if (signbit != (absSum & 1U)) { /* We must find a coeff to toggle up or down so the sign bit of the first non-zero coeff * is properly implied. Note dstCoeff[] are signed by this point but curChange and * finalChange imply absolute levels (+1 is away from zero, -1 is towards zero) */ int64_t minCostInc = MAX_INT64, curCost = MAX_INT64; int minPos = -1; int16_t finalChange = 0, curChange = 0; for (n = (lastCG ? lastNZPosInCG : SCAN_SET_SIZE - 1); n >= 0; --n) { uint32_t blkPos = codeParams.scan[n + subPos]; int signCoef = m_resiDctCoeff[blkPos]; /* pre-quantization DCT coeff */ int absLevel = abs(dstCoeff[blkPos]); int d = abs(signCoef) - UNQUANT(absLevel); int64_t origDist = (((int64_t)d * d)) << scaleBits; #define DELTARDCOST(d, deltabits) ((((int64_t)d * d) << scaleBits) - origDist + ((lambda2 * (int64_t)(deltabits)) >> 8)) if (dstCoeff[blkPos]) { d = abs(signCoef) - UNQUANT(absLevel + 1); int64_t costUp = DELTARDCOST(d, rateIncUp[blkPos]); /* if decrementing would make the coeff 0, we can include the * significant coeff flag cost savings */ d = abs(signCoef) - UNQUANT(absLevel - 1); bool isOne = abs(dstCoeff[blkPos]) == 1; int downBits = rateIncDown[blkPos] - (isOne ? (IEP_RATE + sigRateDelta[blkPos]) : 0); int64_t costDown = DELTARDCOST(d, downBits); if (lastCG && lastNZPosInCG == n && isOne) costDown -= 4 * IEP_RATE; if (costUp < costDown) { curCost = costUp; curChange = 1; } else { curChange = -1; if (n == firstNZPosInCG && isOne) curCost = MAX_INT64; else curCost = costDown; } } else if (n < firstNZPosInCG && signbit != (signCoef >= 0 ? 0 : 1U)) { /* don't try to make a new coded coeff before the first coeff if its * sign would be different than the first coeff, the inferred sign would * still be wrong and we'd have to do this again. */ curCost = MAX_INT64; } else { /* evaluate changing an uncoded coeff 0 to a coded coeff +/-1 */ d = abs(signCoef) - UNQUANT(1); curCost = DELTARDCOST(d, rateIncUp[blkPos] + IEP_RATE + sigRateDelta[blkPos]); curChange = 1; } if (curCost < minCostInc) { minCostInc = curCost; finalChange = curChange; minPos = blkPos; } } if (dstCoeff[minPos] == 32767 || dstCoeff[minPos] == -32768) /* don't allow sign hiding to violate the SPEC range */ finalChange = -1; if (dstCoeff[minPos] == 0) numSig++; else if (finalChange == -1 && abs(dstCoeff[minPos]) == 1) numSig--; if (m_resiDctCoeff[minPos] >= 0) dstCoeff[minPos] += finalChange; else dstCoeff[minPos] -= finalChange; } } lastCG = false; } } return numSig; } /* Pattern decision for context derivation process of significant_coeff_flag */ uint32_t Quant::calcPatternSigCtx(uint64_t sigCoeffGroupFlag64, uint32_t cgPosX, uint32_t cgPosY, uint32_t log2TrSizeCG) { if (!log2TrSizeCG) return 0; const uint32_t trSizeCG = 1 << log2TrSizeCG; X265_CHECK(trSizeCG <= 8, "transform CG is too large\n"); const uint32_t sigPos = (uint32_t)(sigCoeffGroupFlag64 >> (1 + (cgPosY << log2TrSizeCG) + cgPosX)); const uint32_t sigRight = ((int32_t)(cgPosX - (trSizeCG - 1)) >> 31) & (sigPos & 1); const uint32_t sigLower = ((int32_t)(cgPosY - (trSizeCG - 1)) >> 31) & (sigPos >> (trSizeCG - 2)) & 2; return sigRight + sigLower; } /* Context derivation process of coeff_abs_significant_flag */ uint32_t Quant::getSigCtxInc(uint32_t patternSigCtx, uint32_t log2TrSize, uint32_t trSize, uint32_t blkPos, bool bIsLuma, uint32_t firstSignificanceMapContext) { static const uint8_t ctxIndMap[16] = { 0, 1, 4, 5, 2, 3, 4, 5, 6, 6, 8, 8, 7, 7, 8, 8 }; if (!blkPos) // special case for the DC context variable return 0; if (log2TrSize == 2) // 4x4 return ctxIndMap[blkPos]; const uint32_t posY = blkPos >> log2TrSize; const uint32_t posX = blkPos & (trSize - 1); X265_CHECK((blkPos - (posY << log2TrSize)) == posX, "block pos check failed\n"); int posXinSubset = blkPos & 3; X265_CHECK((posX & 3) == (blkPos & 3), "pos alignment fail\n"); int posYinSubset = posY & 3; // NOTE: [patternSigCtx][posXinSubset][posYinSubset] static const uint8_t table_cnt[4][4][4] = { // patternSigCtx = 0 { { 2, 1, 1, 0 }, { 1, 1, 0, 0 }, { 1, 0, 0, 0 }, { 0, 0, 0, 0 }, }, // patternSigCtx = 1 { { 2, 1, 0, 0 }, { 2, 1, 0, 0 }, { 2, 1, 0, 0 }, { 2, 1, 0, 0 }, }, // patternSigCtx = 2 { { 2, 2, 2, 2 }, { 1, 1, 1, 1 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, }, // patternSigCtx = 3 { { 2, 2, 2, 2 }, { 2, 2, 2, 2 }, { 2, 2, 2, 2 }, { 2, 2, 2, 2 }, } }; int cnt = table_cnt[patternSigCtx][posXinSubset][posYinSubset]; int offset = firstSignificanceMapContext; offset += cnt; return (bIsLuma && (posX | posY) >= 4) ? 3 + offset : offset; } /* Calculates the cost of signaling the last significant coefficient in the block */ inline uint32_t Quant::getRateLast(uint32_t posx, uint32_t posy) const { uint32_t ctxX = getGroupIdx(posx); uint32_t ctxY = getGroupIdx(posy); uint32_t cost = m_entropyCoder->m_estBitsSbac.lastXBits[ctxX] + m_entropyCoder->m_estBitsSbac.lastYBits[ctxY]; int32_t maskX = (int32_t)(2 - posx) >> 31; int32_t maskY = (int32_t)(2 - posy) >> 31; cost += maskX & (IEP_RATE * ((ctxX - 2) >> 1)); cost += maskY & (IEP_RATE * ((ctxY - 2) >> 1)); return cost; } /* Context derivation process of coeff_abs_significant_flag */ uint32_t Quant::getSigCoeffGroupCtxInc(uint64_t cgGroupMask, uint32_t cgPosX, uint32_t cgPosY, uint32_t log2TrSizeCG) { const uint32_t trSizeCG = 1 << log2TrSizeCG; const uint32_t sigPos = (uint32_t)(cgGroupMask >> (1 + (cgPosY << log2TrSizeCG) + cgPosX)); const uint32_t sigRight = ((int32_t)(cgPosX - (trSizeCG - 1)) >> 31) & sigPos; const uint32_t sigLower = ((int32_t)(cgPosY - (trSizeCG - 1)) >> 31) & (sigPos >> (trSizeCG - 1)); return (sigRight | sigLower) & 1; }