private bool Decimate(Vp8EncIterator it, ref Vp8ModeScore rd, Vp8RdLevel rdOpt)
{
rd.InitScore();
// We can perform predictions for Luma16x16 and Chroma8x8 already.
// Luma4x4 predictions needs to be done as-we-go.
it.MakeLuma16Preds();
it.MakeChroma8Preds();
if (rdOpt > Vp8RdLevel.RdOptNone)
{
QuantEnc.PickBestIntra16(it, ref rd, this.SegmentInfos, this.Proba);
if (this.method >= WebpEncodingMethod.Level2)
{
QuantEnc.PickBestIntra4(it, ref rd, this.SegmentInfos, this.Proba, this.maxI4HeaderBits);
}
QuantEnc.PickBestUv(it, ref rd, this.SegmentInfos, this.Proba);
}
else
{
// At this point we have heuristically decided intra16 / intra4.
// For method >= 2, pick the best intra4/intra16 based on SSE (~tad slower).
// For method <= 1, we don't re-examine the decision but just go ahead with
// quantization/reconstruction.
QuantEnc.RefineUsingDistortion(it, this.SegmentInfos, rd, this.method >= WebpEncodingMethod.Level2, this.method >= WebpEncodingMethod.Level1, this.MbHeaderLimit);
}
bool isSkipped = rd.Nz == 0;
it.SetSkip(isSkipped);
return(isSkipped);
}
private long OneStatPass(int width, int height, int yStride, int uvStride, Vp8RdLevel rdOpt, int nbMbs, PassStats stats)
{
Span <byte> y = this.Y.GetSpan();
Span <byte> u = this.U.GetSpan();
Span <byte> v = this.V.GetSpan();
var it = new Vp8EncIterator(this.YTop, this.UvTop, this.Nz, this.MbInfo, this.Preds, this.TopDerr, this.Mbw, this.Mbh);
long size = 0;
long sizeP0 = 0;
long distortion = 0;
long pixelCount = nbMbs * 384;
it.Init();
this.SetLoopParams(stats.Q);
var info = new Vp8ModeScore();
do
{
info.Clear();
it.Import(y, u, v, yStride, uvStride, width, height, false);
if (this.Decimate(it, ref info, rdOpt))
{
// Just record the number of skips and act like skipProba is not used.
++this.Proba.NbSkip;
}
this.RecordResiduals(it, info);
size += info.R + info.H;
sizeP0 += info.H;
distortion += info.D;
it.SaveBoundary();
}while (it.Next() && --nbMbs > 0);
sizeP0 += this.SegmentHeader.Size;
if (stats.DoSizeSearch)
{
size += this.Proba.FinalizeSkipProba(this.Mbw, this.Mbh);
size += this.Proba.FinalizeTokenProbas();
size = ((size + sizeP0 + 1024) >> 11) + HeaderSizeEstimate;
stats.Value = size;
}
else
{
stats.Value = GetPsnr(distortion, pixelCount);
}
return(sizeP0);
}
/// <summary>
/// Only collect statistics(number of skips, token usage, ...).
/// This is used for deciding optimal probabilities. It also modifies the
/// quantizer value if some target (size, PSNR) was specified.
/// </summary>
private void StatLoop(int width, int height, int yStride, int uvStride)
{
int targetSize = 0; // TODO: target size is hardcoded.
float targetPsnr = 0.0f; // TODO: targetPsnr is hardcoded.
bool doSearch = targetSize > 0 || targetPsnr > 0;
bool fastProbe = (this.method == 0 || this.method == WebpEncodingMethod.Level3) && !doSearch;
int numPassLeft = this.entropyPasses;
Vp8RdLevel rdOpt = this.method >= WebpEncodingMethod.Level3 || doSearch ? Vp8RdLevel.RdOptBasic : Vp8RdLevel.RdOptNone;
int nbMbs = this.Mbw * this.Mbh;
var stats = new PassStats(targetSize, targetPsnr, QMin, QMax, this.quality);
this.Proba.ResetTokenStats();
// Fast mode: quick analysis pass over few mbs. Better than nothing.
if (fastProbe)
{
if (this.method == WebpEncodingMethod.Level3)
{
// We need more stats for method 3 to be reliable.
nbMbs = nbMbs > 200 ? nbMbs >> 1 : 100;
}
else
{
nbMbs = nbMbs > 200 ? nbMbs >> 2 : 50;
}
}
while (numPassLeft-- > 0)
{
bool isLastPass = (MathF.Abs(stats.Dq) <= DqLimit) || (numPassLeft == 0) || (this.maxI4HeaderBits == 0);
long sizeP0 = this.OneStatPass(width, height, yStride, uvStride, rdOpt, nbMbs, stats);
if (sizeP0 == 0)
{
return;
}
if (this.maxI4HeaderBits > 0 && sizeP0 > (long)Partition0SizeLimit)
{
++numPassLeft;
this.maxI4HeaderBits >>= 1; // strengthen header bit limitation...
continue; // ...and start over
}
if (isLastPass)
{
break;
}
// If no target size: just do several pass without changing 'q'
if (doSearch)
{
stats.ComputeNextQ();
if (MathF.Abs(stats.Dq) <= DqLimit)
{
break;
}
}
}
if (!doSearch || !stats.DoSizeSearch)
{
// Need to finalize probas now, since it wasn't done during the search.
this.Proba.FinalizeSkipProba(this.Mbw, this.Mbh);
this.Proba.FinalizeTokenProbas();
}
// Finalize costs.
this.Proba.CalculateLevelCosts();
}
/// <summary>
/// Initializes a new instance of the <see cref="Vp8Encoder" /> class.
/// </summary>
/// <param name="memoryAllocator">The memory allocator.</param>
/// <param name="configuration">The global configuration.</param>
/// <param name="width">The width of the input image.</param>
/// <param name="height">The height of the input image.</param>
/// <param name="quality">The encoding quality.</param>
/// <param name="method">Quality/speed trade-off (0=fast, 6=slower-better).</param>
/// <param name="entropyPasses">Number of entropy-analysis passes (in [1..10]).</param>
/// <param name="filterStrength">The filter the strength of the deblocking filter, between 0 (no filtering) and 100 (maximum filtering).</param>
/// <param name="spatialNoiseShaping">The spatial noise shaping. 0=off, 100=maximum.</param>
public Vp8Encoder(
MemoryAllocator memoryAllocator,
Configuration configuration,
int width,
int height,
int quality,
WebpEncodingMethod method,
int entropyPasses,
int filterStrength,
int spatialNoiseShaping)
{
this.memoryAllocator = memoryAllocator;
this.configuration = configuration;
this.Width = width;
this.Height = height;
this.quality = Numerics.Clamp(quality, 0, 100);
this.method = method;
this.entropyPasses = Numerics.Clamp(entropyPasses, 1, 10);
this.filterStrength = Numerics.Clamp(filterStrength, 0, 100);
this.spatialNoiseShaping = Numerics.Clamp(spatialNoiseShaping, 0, 100);
this.rdOptLevel = method is WebpEncodingMethod.BestQuality ? Vp8RdLevel.RdOptTrellisAll
: method >= WebpEncodingMethod.Level5 ? Vp8RdLevel.RdOptTrellis
: method >= WebpEncodingMethod.Level3 ? Vp8RdLevel.RdOptBasic
: Vp8RdLevel.RdOptNone;
int pixelCount = width * height;
this.Mbw = (width + 15) >> 4;
this.Mbh = (height + 15) >> 4;
int uvSize = ((width + 1) >> 1) * ((height + 1) >> 1);
this.Y = this.memoryAllocator.Allocate <byte>(pixelCount);
this.U = this.memoryAllocator.Allocate <byte>(uvSize);
this.V = this.memoryAllocator.Allocate <byte>(uvSize);
this.YTop = new byte[this.Mbw * 16];
this.UvTop = new byte[this.Mbw * 16 * 2];
this.Nz = new uint[this.Mbw + 1];
this.MbHeaderLimit = 256 * 510 * 8 * 1024 / (this.Mbw * this.Mbh);
this.TopDerr = new sbyte[this.Mbw * 4];
// TODO: make partition_limit configurable?
int limit = 100; // original code: limit = 100 - config->partition_limit;
this.maxI4HeaderBits =
256 * 16 * 16 * limit * limit / (100 * 100); // ... modulated with a quadratic curve.
this.MbInfo = new Vp8MacroBlockInfo[this.Mbw * this.Mbh];
for (int i = 0; i < this.MbInfo.Length; i++)
{
this.MbInfo[i] = new Vp8MacroBlockInfo();
}
this.SegmentInfos = new Vp8SegmentInfo[4];
for (int i = 0; i < 4; i++)
{
this.SegmentInfos[i] = new Vp8SegmentInfo();
}
this.FilterHeader = new Vp8FilterHeader();
int predSize = (((4 * this.Mbw) + 1) * ((4 * this.Mbh) + 1)) + this.PredsWidth + 1;
this.PredsWidth = (4 * this.Mbw) + 1;
this.Proba = new Vp8EncProba();
this.Preds = new byte[predSize + this.PredsWidth + this.Mbw];
// Initialize with default values, which the reference c implementation uses,
// to be able to compare to the original and spot differences.
this.Preds.AsSpan().Fill(205);
this.Nz.AsSpan().Fill(3452816845);
this.ResetBoundaryPredictions();
}