YCbCrForwardConverter<TPixel>

src/ImageSharp/Formats/Jpeg/GolangPort/Components/Encoder/RgbToYCbCrTables.cs

@@ -9,6 +9,8 @@ using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort.Components.Encoder
 {
+    using System;
+
     /// <summary>
     /// Provides 8-bit lookup tables for converting from Rgb to YCbCr colorspace.
     /// Methods to build the tables are based on libjpeg implementation.
@@ -179,7 +181,29 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort.Components.Encoder
 
         public void Convert(IPixelSource<TPixel> pixels, int x, int y)
         {
+            this.pixelBlock.LoadAndStretchEdges(pixels, x, y);
+
+            Span<Rgb24> rgbSpan = this.rgbBlock.AsSpanUnsafe();
+            PixelOperations<TPixel>.Instance.ToRgb24(this.pixelBlock.AsSpanUnsafe(), rgbSpan, 64);
+
+            ref float yBlockStart = ref Unsafe.As<Block8x8F, float>(ref this.Y);
+            ref float cbBlockStart = ref Unsafe.As<Block8x8F, float>(ref this.Cb);
+            ref float crBlockStart = ref Unsafe.As<Block8x8F, float>(ref this.Cr);
+            ref Rgb24 rgbStart = ref rgbSpan[0];
 
+            for (int i = 0; i < 64; i++)
+            {
+                ref Rgb24 c = ref Unsafe.Add(ref rgbStart, i);
+
+                this.colorTables.ConvertPixelInto(
+                    c.R,
+                    c.G,
+                    c.B,
+                    ref Unsafe.Add(ref yBlockStart, i),
+                    ref Unsafe.Add(ref cbBlockStart, i),
+                    ref Unsafe.Add(ref crBlockStart, i)
+                    );
+            }
         }
     }
 }

src/ImageSharp/Formats/Jpeg/GolangPort/JpegEncoderCore.cs

@@ -313,11 +313,6 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
             ref float cbBlockStart = ref Unsafe.As<Block8x8F, float>(ref cbBlock);
             ref float crBlockStart = ref Unsafe.As<Block8x8F, float>(ref crBlock);
 
-            float* yBlockRaw = (float*) Unsafe.AsPointer(ref yBlock);
-            float* cbBlockRaw = (float*)Unsafe.AsPointer(ref cbBlock);
-            float* crBlockRaw = (float*)Unsafe.AsPointer(ref crBlock);
-
-            rgbBytes.Reset();
             pixels.CopyRGBBytesStretchedTo(rgbBytes, y, x);
 
             ref byte data0 = ref rgbBytes.Bytes[0];
@@ -335,14 +330,14 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
 
                     int index = j8 + i;
 
-                    RgbToYCbCrTables.Rgb2YCbCr(tables, yBlockRaw, cbBlockRaw, crBlockRaw, index, r, g, b);
-                    //tables->ConvertPixelInto(
-                    //    r,
-                    //    g,
-                    //    b,
-                    //    ref Unsafe.Add(ref yBlockRaw, index),
-                    //    ref Unsafe.Add(ref cbBlockRaw, index),
-                    //    ref Unsafe.Add(ref crBlockRaw, index));
+                    // RgbToYCbCrTables.Rgb2YCbCr(tables, yBlockRaw, cbBlockRaw, crBlockRaw, index, r, g, b);
+                    tables->ConvertPixelInto(
+                        r,
+                        g,
+                        b,
+                        ref Unsafe.Add(ref yBlockStart, index),
+                        ref Unsafe.Add(ref cbBlockStart, index),
+                        ref Unsafe.Add(ref crBlockStart, index));
 
                     dataIdx += 3;
                 }
@@ -463,6 +458,8 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
             // ReSharper disable once InconsistentNaming
             int prevDCY = 0, prevDCCb = 0, prevDCCr = 0;
 
+            YCbCrForwardConverter<TPixel> pixelConverter = YCbCrForwardConverter<TPixel>.Create();
+
             fixed (RgbToYCbCrTables* tables = &rgbToYCbCrTables)
             {
                 using (PixelArea<TPixel> rgbBytes = new PixelArea<TPixel>(8, 8, ComponentOrder.Xyz))