// Refine intra16/intra4 sub-modes based on distortion only (not rate). public static void RefineUsingDistortion(Vp8EncIterator it, Vp8SegmentInfo[] segmentInfos, Vp8ModeScore rd, bool tryBothModes, bool refineUvMode, int mbHeaderLimit) { long bestScore = Vp8ModeScore.MaxCost; int nz = 0; int mode; bool isI16 = tryBothModes || it.CurrentMacroBlockInfo.MacroBlockType == Vp8MacroBlockType.I16X16; Vp8SegmentInfo dqm = segmentInfos[it.CurrentMacroBlockInfo.Segment]; // Some empiric constants, of approximate order of magnitude. const int lambdaDi16 = 106; const int lambdaDi4 = 11; const int lambdaDuv = 120; long scoreI4 = dqm.I4Penalty; long i4BitSum = 0; long bitLimit = tryBothModes ? mbHeaderLimit : Vp8ModeScore.MaxCost; // no early-out allowed. if (isI16) { int bestMode = -1; Span <byte> src = it.YuvIn.AsSpan(Vp8EncIterator.YOffEnc); for (mode = 0; mode < WebpConstants.NumPredModes; ++mode) { Span <byte> reference = it.YuvP.AsSpan(Vp8Encoding.Vp8I16ModeOffsets[mode]); long score = (LossyUtils.Vp8_Sse16X16(src, reference) * WebpConstants.RdDistoMult) + (WebpConstants.Vp8FixedCostsI16[mode] * lambdaDi16); if (mode > 0 && WebpConstants.Vp8FixedCostsI16[mode] > bitLimit) { continue; } if (score < bestScore) { bestMode = mode; bestScore = score; } } if (it.X == 0 || it.Y == 0) { // Avoid starting a checkerboard resonance from the border. See bug #432 of libwebp. if (IsFlatSource16(src)) { bestMode = it.X == 0 ? 0 : 2; tryBothModes = false; // Stick to i16. } } it.SetIntra16Mode(bestMode); // We'll reconstruct later, if i16 mode actually gets selected. } // Next, evaluate Intra4. if (tryBothModes || !isI16) { // We don't evaluate the rate here, but just account for it through a // constant penalty (i4 mode usually needs more bits compared to i16). isI16 = false; it.StartI4(); do { int bestI4Mode = -1; long bestI4Score = Vp8ModeScore.MaxCost; Span <byte> src = it.YuvIn.AsSpan(Vp8EncIterator.YOffEnc + WebpLookupTables.Vp8Scan[it.I4]); short[] modeCosts = it.GetCostModeI4(rd.ModesI4); it.MakeIntra4Preds(); for (mode = 0; mode < WebpConstants.NumBModes; ++mode) { Span <byte> reference = it.YuvP.AsSpan(Vp8Encoding.Vp8I4ModeOffsets[mode]); long score = (LossyUtils.Vp8_Sse4X4(src, reference) * WebpConstants.RdDistoMult) + (modeCosts[mode] * lambdaDi4); if (score < bestI4Score) { bestI4Mode = mode; bestI4Score = score; } } i4BitSum += modeCosts[bestI4Mode]; rd.ModesI4[it.I4] = (byte)bestI4Mode; scoreI4 += bestI4Score; if (scoreI4 >= bestScore || i4BitSum > bitLimit) { // Intra4 won't be better than Intra16. Bail out and pick Intra16. isI16 = true; break; } else { // Reconstruct partial block inside YuvOut2 buffer Span <byte> tmpDst = it.YuvOut2.AsSpan(Vp8EncIterator.YOffEnc + WebpLookupTables.Vp8Scan[it.I4]); nz |= ReconstructIntra4(it, dqm, rd.YAcLevels.AsSpan(it.I4 * 16, 16), src, tmpDst, bestI4Mode) << it.I4; } }while (it.RotateI4(it.YuvOut2.AsSpan(Vp8EncIterator.YOffEnc))); } // Final reconstruction, depending on which mode is selected. if (!isI16) { it.SetIntra4Mode(rd.ModesI4); it.SwapOut(); bestScore = scoreI4; } else { int intra16Mode = it.Preds[it.PredIdx]; nz = ReconstructIntra16(it, dqm, rd, it.YuvOut.AsSpan(Vp8EncIterator.YOffEnc), intra16Mode); } // ... and UV! if (refineUvMode) { int bestMode = -1; long bestUvScore = Vp8ModeScore.MaxCost; Span <byte> src = it.YuvIn.AsSpan(Vp8EncIterator.UOffEnc); for (mode = 0; mode < WebpConstants.NumPredModes; ++mode) { Span <byte> reference = it.YuvP.AsSpan(Vp8Encoding.Vp8UvModeOffsets[mode]); long score = (LossyUtils.Vp8_Sse16X8(src, reference) * WebpConstants.RdDistoMult) + (WebpConstants.Vp8FixedCostsUv[mode] * lambdaDuv); if (score < bestUvScore) { bestMode = mode; bestUvScore = score; } } it.SetIntraUvMode(bestMode); } nz |= ReconstructUv(it, dqm, rd, it.YuvOut.AsSpan(Vp8EncIterator.UOffEnc), it.CurrentMacroBlockInfo.UvMode); rd.Nz = (uint)nz; rd.Score = bestScore; }
public static void PickBestUv(Vp8EncIterator it, ref Vp8ModeScore rd, Vp8SegmentInfo[] segmentInfos, Vp8EncProba proba) { const int numBlocks = 8; Vp8SegmentInfo dqm = segmentInfos[it.CurrentMacroBlockInfo.Segment]; int lambda = dqm.LambdaUv; Span <byte> src = it.YuvIn.AsSpan(Vp8EncIterator.UOffEnc); Span <byte> tmpDst = it.YuvOut2.AsSpan(Vp8EncIterator.UOffEnc); Span <byte> dst0 = it.YuvOut.AsSpan(Vp8EncIterator.UOffEnc); Span <byte> dst = dst0; var rdBest = new Vp8ModeScore(); var rdUv = new Vp8ModeScore(); var res = new Vp8Residual(); int mode; rd.ModeUv = -1; rdBest.InitScore(); for (mode = 0; mode < WebpConstants.NumPredModes; ++mode) { rdUv.Clear(); // Reconstruct rdUv.Nz = (uint)ReconstructUv(it, dqm, rdUv, tmpDst, mode); // Compute RD-score rdUv.D = LossyUtils.Vp8_Sse16X8(src, tmpDst); rdUv.SD = 0; // not calling TDisto here: it tends to flatten areas. rdUv.H = WebpConstants.Vp8FixedCostsUv[mode]; rdUv.R = it.GetCostUv(rdUv, proba, res); if (mode > 0 && IsFlat(rdUv.UvLevels, numBlocks, WebpConstants.FlatnessLimitIUv)) { rdUv.R += WebpConstants.FlatnessPenality * numBlocks; } rdUv.SetRdScore(lambda); if (mode == 0 || rdUv.Score < rdBest.Score) { rdBest.CopyScore(rdUv); rd.ModeUv = mode; rdUv.UvLevels.CopyTo(rd.UvLevels.AsSpan()); for (int i = 0; i < 2; i++) { rd.Derr[i, 0] = rdUv.Derr[i, 0]; rd.Derr[i, 1] = rdUv.Derr[i, 1]; rd.Derr[i, 2] = rdUv.Derr[i, 2]; } Span <byte> tmp = dst; dst = tmpDst; tmpDst = tmp; } } it.SetIntraUvMode(rd.ModeUv); rd.AddScore(rdBest); if (dst != dst0) { // copy 16x8 block if needed. LossyUtils.Vp8Copy16X8(dst, dst0); } // Store diffusion errors for next block. it.StoreDiffusionErrors(rd); }