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 int MbAnalyze(Vp8EncIterator it, int[] alphas, out int bestUvAlpha)
{
it.SetIntra16Mode(0); // default: Intra16, DC_PRED
it.SetSkip(false); // not skipped.
it.SetSegment(0); // default segment, spec-wise.
int bestAlpha;
if (this.method <= WebpEncodingMethod.Level1)
{
bestAlpha = it.FastMbAnalyze(this.quality);
}
else
{
bestAlpha = it.MbAnalyzeBestIntra16Mode();
if (this.method >= WebpEncodingMethod.Level5)
{
// We go and make a fast decision for intra4/intra16.
// It's usually not a good and definitive pick, but helps seeding the stats about level bit-cost.
bestAlpha = it.MbAnalyzeBestIntra4Mode(bestAlpha);
}
}
bestUvAlpha = it.MbAnalyzeBestUvMode();
// Final susceptibility mix.
bestAlpha = ((3 * bestAlpha) + bestUvAlpha + 2) >> 2;
bestAlpha = FinalAlphaValue(bestAlpha);
alphas[bestAlpha]++;
it.CurrentMacroBlockInfo.Alpha = bestAlpha; // For later remapping.
return(bestAlpha); // Mixed susceptibility (not just luma).
}