public int MbAnalyzeBestUvMode()
{
int bestAlpha = DefaultAlpha;
int smallestAlpha = 0;
int bestMode = 0;
int maxMode = MaxUvMode;
int mode;
this.MakeChroma8Preds();
for (mode = 0; mode < maxMode; ++mode)
{
var histo = new Vp8Histogram();
histo.CollectHistogram(this.YuvIn.AsSpan(UOffEnc), this.YuvP.AsSpan(Vp8Encoding.Vp8UvModeOffsets[mode]), 16, 16 + 4 + 4);
int alpha = histo.GetAlpha();
if (alpha > bestAlpha)
{
bestAlpha = alpha;
}
// The best prediction mode tends to be the one with the smallest alpha.
if (mode == 0 || alpha < smallestAlpha)
{
smallestAlpha = alpha;
bestMode = mode;
}
}
this.SetIntraUvMode(bestMode);
return(bestAlpha);
}
public int MbAnalyzeBestIntra16Mode()
{
int maxMode = MaxIntra16Mode;
int mode;
int bestAlpha = DefaultAlpha;
int bestMode = 0;
this.MakeLuma16Preds();
for (mode = 0; mode < maxMode; mode++)
{
var histo = new Vp8Histogram();
histo.CollectHistogram(this.YuvIn.AsSpan(YOffEnc), this.YuvP.AsSpan(Vp8Encoding.Vp8I16ModeOffsets[mode]), 0, 16);
int alpha = histo.GetAlpha();
if (alpha > bestAlpha)
{
bestAlpha = alpha;
bestMode = mode;
}
}
this.SetIntra16Mode(bestMode);
return(bestAlpha);
}
