public int GetCostLuma16(Vp8ModeScore rd, Vp8EncProba proba, Vp8Residual res)
{
int r = 0;
// re-import the non-zero context.
this.NzToBytes();
// DC
res.Init(0, 1, proba);
res.SetCoeffs(rd.YDcLevels);
r += res.GetResidualCost(this.TopNz[8] + this.LeftNz[8]);
// AC
res.Init(1, 0, proba);
for (int y = 0; y < 4; y++)
{
for (int x = 0; x < 4; x++)
{
int ctx = this.TopNz[x] + this.LeftNz[y];
res.SetCoeffs(rd.YAcLevels.AsSpan((x + (y * 4)) * 16, 16));
r += res.GetResidualCost(ctx);
this.TopNz[x] = this.LeftNz[y] = res.Last >= 0 ? 1 : 0;
}
}
return(r);
}
/// <summary>
/// Same as CodeResiduals, but doesn't actually write anything.
/// Instead, it just records the event distribution.
/// </summary>
private void RecordResiduals(Vp8EncIterator it, Vp8ModeScore rd)
{
int x, y, ch;
var residual = new Vp8Residual();
bool i16 = it.CurrentMacroBlockInfo.MacroBlockType == Vp8MacroBlockType.I16X16;
it.NzToBytes();
if (i16)
{
// i16x16
residual.Init(0, 1, this.Proba);
residual.SetCoeffs(rd.YDcLevels);
int res = residual.RecordCoeffs(it.TopNz[8] + it.LeftNz[8]);
it.TopNz[8] = res;
it.LeftNz[8] = res;
residual.Init(1, 0, this.Proba);
}
else
{
residual.Init(0, 3, this.Proba);
}
// luma-AC
for (y = 0; y < 4; y++)
{
for (x = 0; x < 4; x++)
{
int ctx = it.TopNz[x] + it.LeftNz[y];
Span <short> coeffs = rd.YAcLevels.AsSpan(16 * (x + (y * 4)), 16);
residual.SetCoeffs(coeffs);
int res = residual.RecordCoeffs(ctx);
it.TopNz[x] = res;
it.LeftNz[y] = res;
}
}
// U/V
residual.Init(0, 2, this.Proba);
for (ch = 0; ch <= 2; ch += 2)
{
for (y = 0; y < 2; y++)
{
for (x = 0; x < 2; x++)
{
int ctx = it.TopNz[4 + ch + x] + it.LeftNz[4 + ch + y];
residual.SetCoeffs(rd.UvLevels.AsSpan(16 * ((ch * 2) + x + (y * 2)), 16));
int res = residual.RecordCoeffs(ctx);
it.TopNz[4 + ch + x] = res;
it.LeftNz[4 + ch + y] = res;
}
}
}
it.BytesToNz();
}
public int GetCostLuma4(Span <short> levels, Vp8EncProba proba, Vp8Residual res)
{
int x = this.I4 & 3;
int y = this.I4 >> 2;
int r = 0;
res.Init(0, 3, proba);
int ctx = this.TopNz[x] + this.LeftNz[y];
res.SetCoeffs(levels);
r += res.GetResidualCost(ctx);
return(r);
}
public int GetCostUv(Vp8ModeScore rd, Vp8EncProba proba, Vp8Residual res)
{
int r = 0;
// re-import the non-zero context.
this.NzToBytes();
res.Init(0, 2, proba);
for (int ch = 0; ch <= 2; ch += 2)
{
for (int y = 0; y < 2; y++)
{
for (int x = 0; x < 2; x++)
{
int ctx = this.TopNz[4 + ch + x] + this.LeftNz[4 + ch + y];
res.SetCoeffs(rd.UvLevels.AsSpan(((ch * 2) + x + (y * 2)) * 16, 16));
r += res.GetResidualCost(ctx);
this.TopNz[4 + ch + x] = this.LeftNz[4 + ch + y] = res.Last >= 0 ? 1 : 0;
}
}
}
return(r);
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="Image{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : unmanaged, IPixel <TPixel>
{
int width = image.Width;
int height = image.Height;
Span <byte> y = this.Y.GetSpan();
Span <byte> u = this.U.GetSpan();
Span <byte> v = this.V.GetSpan();
YuvConversion.ConvertRgbToYuv(image, this.configuration, this.memoryAllocator, y, u, v);
int yStride = width;
int uvStride = (yStride + 1) >> 1;
var it = new Vp8EncIterator(this.YTop, this.UvTop, this.Nz, this.MbInfo, this.Preds, this.TopDerr, this.Mbw, this.Mbh);
int[] alphas = new int[WebpConstants.MaxAlpha + 1];
this.alpha = this.MacroBlockAnalysis(width, height, it, y, u, v, yStride, uvStride, alphas, out this.uvAlpha);
int totalMb = this.Mbw * this.Mbw;
this.alpha /= totalMb;
this.uvAlpha /= totalMb;
// Analysis is done, proceed to actual encoding.
this.SegmentHeader = new Vp8EncSegmentHeader(4);
this.AssignSegments(alphas);
this.SetLoopParams(this.quality);
// Initialize the bitwriter.
int averageBytesPerMacroBlock = this.averageBytesPerMb[this.BaseQuant >> 4];
int expectedSize = this.Mbw * this.Mbh * averageBytesPerMacroBlock;
this.bitWriter = new Vp8BitWriter(expectedSize, this);
// TODO: EncodeAlpha();
bool hasAlpha = false;
// Stats-collection loop.
this.StatLoop(width, height, yStride, uvStride);
it.Init();
it.InitFilter();
var info = new Vp8ModeScore();
var residual = new Vp8Residual();
do
{
bool dontUseSkip = !this.Proba.UseSkipProba;
info.Clear();
it.Import(y, u, v, yStride, uvStride, width, height, false);
// Warning! order is important: first call VP8Decimate() and
// *then* decide how to code the skip decision if there's one.
if (!this.Decimate(it, ref info, this.rdOptLevel) || dontUseSkip)
{
this.CodeResiduals(it, info, residual);
}
else
{
it.ResetAfterSkip();
}
it.SaveBoundary();
}while (it.Next());
// Store filter stats.
this.AdjustFilterStrength();
// Write bytes from the bitwriter buffer to the stream.
image.Metadata.SyncProfiles();
this.bitWriter.WriteEncodedImageToStream(stream, image.Metadata.ExifProfile, (uint)width, (uint)height, hasAlpha);
}
private void CodeResiduals(Vp8EncIterator it, Vp8ModeScore rd, Vp8Residual residual)
{
int x, y, ch;
bool i16 = it.CurrentMacroBlockInfo.MacroBlockType == Vp8MacroBlockType.I16X16;
int segment = it.CurrentMacroBlockInfo.Segment;
it.NzToBytes();
int pos1 = this.bitWriter.NumBytes();
if (i16)
{
residual.Init(0, 1, this.Proba);
residual.SetCoeffs(rd.YDcLevels);
int res = this.bitWriter.PutCoeffs(it.TopNz[8] + it.LeftNz[8], residual);
it.TopNz[8] = it.LeftNz[8] = res;
residual.Init(1, 0, this.Proba);
}
else
{
residual.Init(0, 3, this.Proba);
}
// luma-AC
for (y = 0; y < 4; y++)
{
for (x = 0; x < 4; x++)
{
int ctx = it.TopNz[x] + it.LeftNz[y];
Span <short> coeffs = rd.YAcLevels.AsSpan(16 * (x + (y * 4)), 16);
residual.SetCoeffs(coeffs);
int res = this.bitWriter.PutCoeffs(ctx, residual);
it.TopNz[x] = it.LeftNz[y] = res;
}
}
int pos2 = this.bitWriter.NumBytes();
// U/V
residual.Init(0, 2, this.Proba);
for (ch = 0; ch <= 2; ch += 2)
{
for (y = 0; y < 2; y++)
{
for (x = 0; x < 2; x++)
{
int ctx = it.TopNz[4 + ch + x] + it.LeftNz[4 + ch + y];
residual.SetCoeffs(rd.UvLevels.AsSpan(16 * ((ch * 2) + x + (y * 2)), 16));
int res = this.bitWriter.PutCoeffs(ctx, residual);
it.TopNz[4 + ch + x] = it.LeftNz[4 + ch + y] = res;
}
}
}
int pos3 = this.bitWriter.NumBytes();
it.LumaBits = pos2 - pos1;
it.UvBits = pos3 - pos2;
it.BitCount[segment, i16 ? 1 : 0] += it.LumaBits;
it.BitCount[segment, 2] += it.UvBits;
it.BytesToNz();
}
private const int DSCALE = 1; // storage descaling, needed to make the error fit byte
public static void PickBestIntra16(Vp8EncIterator it, ref Vp8ModeScore rd, Vp8SegmentInfo[] segmentInfos, Vp8EncProba proba)
{
const int numBlocks = 16;
Vp8SegmentInfo dqm = segmentInfos[it.CurrentMacroBlockInfo.Segment];
int lambda = dqm.LambdaI16;
int tlambda = dqm.TLambda;
Span <byte> src = it.YuvIn.AsSpan(Vp8EncIterator.YOffEnc);
Span <int> scratch = it.Scratch3;
var rdTmp = new Vp8ModeScore();
var res = new Vp8Residual();
Vp8ModeScore rdCur = rdTmp;
Vp8ModeScore rdBest = rd;
int mode;
bool isFlat = IsFlatSource16(src);
rd.ModeI16 = -1;
for (mode = 0; mode < WebpConstants.NumPredModes; ++mode)
{
// Scratch buffer.
Span <byte> tmpDst = it.YuvOut2.AsSpan(Vp8EncIterator.YOffEnc);
rdCur.ModeI16 = mode;
// Reconstruct.
rdCur.Nz = (uint)ReconstructIntra16(it, dqm, rdCur, tmpDst, mode);
// Measure RD-score.
rdCur.D = LossyUtils.Vp8_Sse16X16(src, tmpDst);
rdCur.SD = tlambda != 0 ? Mult8B(tlambda, LossyUtils.Vp8Disto16X16(src, tmpDst, WeightY, scratch)) : 0;
rdCur.H = WebpConstants.Vp8FixedCostsI16[mode];
rdCur.R = it.GetCostLuma16(rdCur, proba, res);
if (isFlat)
{
// Refine the first impression (which was in pixel space).
isFlat = IsFlat(rdCur.YAcLevels, numBlocks, WebpConstants.FlatnessLimitI16);
if (isFlat)
{
// Block is very flat. We put emphasis on the distortion being very low!
rdCur.D *= 2;
rdCur.SD *= 2;
}
}
// Since we always examine Intra16 first, we can overwrite *rd directly.
rdCur.SetRdScore(lambda);
if (mode == 0 || rdCur.Score < rdBest.Score)
{
Vp8ModeScore tmp = rdCur;
rdCur = rdBest;
rdBest = tmp;
it.SwapOut();
}
}
if (rdBest != rd)
{
rd = rdBest;
}
// Finalize score for mode decision.
rd.SetRdScore(dqm.LambdaMode);
it.SetIntra16Mode(rd.ModeI16);
// We have a blocky macroblock (only DCs are non-zero) with fairly high
// distortion, record max delta so we can later adjust the minimal filtering
// strength needed to smooth these blocks out.
if ((rd.Nz & 0x100ffff) == 0x1000000 && rd.D > dqm.MinDisto)
{
dqm.StoreMaxDelta(rd.YDcLevels);
}
}
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);
}
public static bool PickBestIntra4(Vp8EncIterator it, ref Vp8ModeScore rd, Vp8SegmentInfo[] segmentInfos, Vp8EncProba proba, int maxI4HeaderBits)
{
Vp8SegmentInfo dqm = segmentInfos[it.CurrentMacroBlockInfo.Segment];
int lambda = dqm.LambdaI4;
int tlambda = dqm.TLambda;
Span <byte> src0 = it.YuvIn.AsSpan(Vp8EncIterator.YOffEnc);
Span <byte> bestBlocks = it.YuvOut2.AsSpan(Vp8EncIterator.YOffEnc);
Span <int> scratch = it.Scratch3;
int totalHeaderBits = 0;
var rdBest = new Vp8ModeScore();
if (maxI4HeaderBits == 0)
{
return(false);
}
rdBest.InitScore();
rdBest.H = 211; // '211' is the value of VP8BitCost(0, 145)
rdBest.SetRdScore(dqm.LambdaMode);
it.StartI4();
var rdi4 = new Vp8ModeScore();
var rdTmp = new Vp8ModeScore();
var res = new Vp8Residual();
Span <short> tmpLevels = new short[16];
do
{
int numBlocks = 1;
rdi4.Clear();
int mode;
int bestMode = -1;
Span <byte> src = src0.Slice(WebpLookupTables.Vp8Scan[it.I4]);
short[] modeCosts = it.GetCostModeI4(rd.ModesI4);
Span <byte> bestBlock = bestBlocks.Slice(WebpLookupTables.Vp8Scan[it.I4]);
Span <byte> tmpDst = it.Scratch.AsSpan();
tmpDst.Clear();
rdi4.InitScore();
it.MakeIntra4Preds();
for (mode = 0; mode < WebpConstants.NumBModes; ++mode)
{
rdTmp.Clear();
tmpLevels.Clear();
// Reconstruct.
rdTmp.Nz = (uint)ReconstructIntra4(it, dqm, tmpLevels, src, tmpDst, mode);
// Compute RD-score.
rdTmp.D = LossyUtils.Vp8_Sse4X4(src, tmpDst);
rdTmp.SD = tlambda != 0 ? Mult8B(tlambda, LossyUtils.Vp8Disto4X4(src, tmpDst, WeightY, scratch)) : 0;
rdTmp.H = modeCosts[mode];
// Add flatness penalty, to avoid flat area to be mispredicted by a complex mode.
if (mode > 0 && IsFlat(tmpLevels, numBlocks, WebpConstants.FlatnessLimitI4))
{
rdTmp.R = WebpConstants.FlatnessPenality * numBlocks;
}
else
{
rdTmp.R = 0;
}
// Early-out check.
rdTmp.SetRdScore(lambda);
if (bestMode >= 0 && rdTmp.Score >= rdi4.Score)
{
continue;
}
// Finish computing score.
rdTmp.R += it.GetCostLuma4(tmpLevels, proba, res);
rdTmp.SetRdScore(lambda);
if (bestMode < 0 || rdTmp.Score < rdi4.Score)
{
rdi4.CopyScore(rdTmp);
bestMode = mode;
Span <byte> tmp = tmpDst;
tmpDst = bestBlock;
bestBlock = tmp;
tmpLevels.CopyTo(rdBest.YAcLevels.AsSpan(it.I4 * 16, 16));
}
}
rdi4.SetRdScore(dqm.LambdaMode);
rdBest.AddScore(rdi4);
if (rdBest.Score >= rd.Score)
{
return(false);
}
totalHeaderBits += (int)rdi4.H; // <- equal to modeCosts[bestMode];
if (totalHeaderBits > maxI4HeaderBits)
{
return(false);
}
// Copy selected samples to the right place.
LossyUtils.Vp8Copy4X4(bestBlock, bestBlocks.Slice(WebpLookupTables.Vp8Scan[it.I4]));
rd.ModesI4[it.I4] = (byte)bestMode;
it.TopNz[it.I4 & 3] = it.LeftNz[it.I4 >> 2] = rdi4.Nz != 0 ? 1 : 0;
}while (it.RotateI4(bestBlocks));
// Finalize state.
rd.CopyScore(rdBest);
it.SetIntra4Mode(rd.ModesI4);
it.SwapOut();
rdBest.YAcLevels.AsSpan().CopyTo(rd.YAcLevels);
// Select intra4x4 over intra16x16.
return(true);
}
