Add references to SVT library method names

src/ImageSharp/Formats/Heif/Av1/Pipeline/Av1FrameDecoder.cs

@@ -95,6 +95,9 @@ internal class Av1FrameDecoder
         }
     }
 
+    /// <summary>
+    /// SVT: svt_aom_decode_super_block
+    /// </summary>
     private void DecodeSuperblock(Point modeInfoPosition, Av1SuperblockInfo superblockInfo, Av1TileInfo tileInfo)
     {
         this.blockDecoder.UpdateSuperblock(superblockInfo);
@@ -102,6 +105,9 @@ internal class Av1FrameDecoder
         this.DecodePartition(modeInfoPosition, superblockInfo, tileInfo);
     }
 
+    /// <summary>
+    /// SVT: decode_partition
+    /// </summary>
     private void DecodePartition(Point modeInfoPosition, Av1SuperblockInfo superblockInfo, Av1TileInfo tileInfo)
     {
         Av1BlockModeInfo modeInfo = superblockInfo.GetModeInfo(modeInfoPosition);

src/ImageSharp/Formats/Heif/Av1/Pipeline/Quantification/Av1InverseQuantizer.cs

@@ -78,6 +78,9 @@ internal class Av1InverseQuantizer
         }
     }
 
+    /// <summary>
+    /// SVT: svt_aom_inverse_quantize
+    /// </summary>
     public int InverseQuantize(Av1BlockModeInfo mode, Span<int> level, Span<int> qCoefficients, Av1TransformType transformType, Av1TransformSize transformSize, Av1Plane plane)
     {
         Guard.NotNull(this.deQuantsDeltaQ);
@@ -135,12 +138,15 @@ internal class Av1InverseQuantizer
         return coefficientCount;
     }
 
+    /// <summary>
+    /// SVT: get_dqv
+    /// </summary>
     private static int GetDeQuantizedValue(short dequant, int coefficientIndex, ref int iqMatrix)
     {
+        const int bias = 1 << (Av1ScanOrderConstants.QuantizationMatrixLevelBitCount - 1);
         int deQuantifiedValue = dequant;
 
-        // TODO: Check order of operators
-        deQuantifiedValue = ((Unsafe.Add(ref iqMatrix, coefficientIndex) * deQuantifiedValue) + (1 << (Av1ScanOrderConstants.QuantizationMatrixLevelBitCount - 1))) >> Av1ScanOrderConstants.QuantizationMatrixLevelBitCount;
+        deQuantifiedValue = ((Unsafe.Add(ref iqMatrix, coefficientIndex) * deQuantifiedValue) + bias) >> Av1ScanOrderConstants.QuantizationMatrixLevelBitCount;
         return deQuantifiedValue;
     }
 }

src/ImageSharp/Formats/Heif/Av1/Transform/Av1BlockDecoder.cs

@@ -183,8 +183,6 @@ internal class Av1BlockDecoder
                                 quantizationCoefficients,
                                 transformBlockReconstructionBuffer,
                                 reconstructionStride,
-                                transformBlockReconstructionBuffer,
-                                reconstructionStride,
                                 transformSize,
                                 transformType,
                                 plane,

src/ImageSharp/Formats/Heif/Av1/Transform/Av1InverseTransformer.cs

@@ -8,7 +8,7 @@ internal class Av1InverseTransformer
     /// <summary>
     /// SVT: svt_aom_inv_transform_recon8bit
     /// </summary>
-    public static void Reconstruct8Bit(Span<int> coefficientsBuffer, Span<byte> reconstructionBufferRead, int reconstructionReadStride, Span<byte> reconstructionBufferWrite, int reconstructionWriteStride, Av1TransformSize transformSize, Av1TransformType transformType, int plane, int numberOfCoefficients, bool isLossless)
+    public static void Reconstruct8Bit(Span<int> coefficientsBuffer, Span<byte> reconstructionBuffer, int reconstructionStride, Av1TransformSize transformSize, Av1TransformType transformType, int plane, int numberOfCoefficients, bool isLossless)
     {
         Av1TransformFunctionParameters transformFunctionParameters = new()
         {
@@ -20,33 +20,31 @@ internal class Av1InverseTransformer
             Is16BitPipeline = false
         };
 
-        if (reconstructionBufferRead != reconstructionBufferWrite)
-        {
-            /* When output pointers to read and write are differents,
-             * then kernel copy also all buffer from read to write,
-             * and cannot be limited by End Of Buffer calculations. */
-            transformFunctionParameters.EndOfBuffer = GetMaxEndOfBuffer(transformSize);
-        }
-
         Av1InverseTransformerFactory.InverseTransformAdd(
-            coefficientsBuffer, reconstructionBufferRead, reconstructionReadStride, reconstructionBufferWrite, reconstructionWriteStride, transformFunctionParameters);
+            coefficientsBuffer, reconstructionBuffer, reconstructionStride, reconstructionBuffer, reconstructionStride, transformFunctionParameters);
     }
 
     /// <summary>
-    /// SVT: av1_get_max_eob
+    /// SVT: svt_aom_inv_transform_recon8bit
     /// </summary>
-    private static int GetMaxEndOfBuffer(Av1TransformSize transformSize)
+    public static void Reconstruct8Bit(Span<int> coefficientsBuffer, Span<byte> reconstructionBufferRead, int reconstructionReadStride, Span<byte> reconstructionBufferWrite, int reconstructionWriteStride, Av1TransformSize transformSize, Av1TransformType transformType, int plane, int numberOfCoefficients, bool isLossless)
     {
-        if (transformSize is Av1TransformSize.Size64x64 or Av1TransformSize.Size64x32 or Av1TransformSize.Size32x64)
+        Av1TransformFunctionParameters transformFunctionParameters = new()
         {
-            return 1024;
-        }
+            TransformType = transformType,
+            TransformSize = transformSize,
+            EndOfBuffer = numberOfCoefficients,
+            IsLossless = isLossless,
+            BitDepth = 8,
+            Is16BitPipeline = false
+        };
 
-        if (transformSize is Av1TransformSize.Size16x64 or Av1TransformSize.Size64x16)
-        {
-            return 512;
-        }
+        /* When output pointers to read and write are differents,
+        * then kernel copy also all buffer from read to write,
+        * and cannot be limited by End Of Buffer calculations. */
+        transformFunctionParameters.EndOfBuffer = Av1InverseTransformMath.GetMaxEndOfBuffer(transformSize);
 
-        return transformSize.GetSize2d();
+        Av1InverseTransformerFactory.InverseTransformAdd(
+            coefficientsBuffer, reconstructionBufferRead, reconstructionReadStride, reconstructionBufferWrite, reconstructionWriteStride, transformFunctionParameters);
     }
 }

src/ImageSharp/Formats/Heif/Av1/Transform/Av1InverseTransformerFactory.cs

@@ -7,6 +7,9 @@ namespace SixLabors.ImageSharp.Formats.Heif.Av1.Transform;
 
 internal static class Av1InverseTransformerFactory
 {
+    /// <summary>
+    /// SVT: svt_av1_inv_txfm_add
+    /// </summary>
     public static unsafe void InverseTransformAdd(Span<int> coefficients, Span<byte> readBuffer, int readStride, Span<byte> writeBuffer, int writeStride, Av1TransformFunctionParameters transformFunctionParameters)
     {
         Guard.MustBeLessThanOrEqualTo(transformFunctionParameters.BitDepth, 8, nameof(transformFunctionParameters));