Implement TransformBlock

src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs

@@ -50,6 +50,9 @@ internal static class Av1BlockSizeExtensions
         Av1TransformSize.Size16x64, Av1TransformSize.Size64x16
     ];
 
+    private static readonly int[] PelsLog2Count =
+        [4, 5, 5, 6, 7, 7, 8, 9, 9, 10, 11, 11, 12, 13, 13, 14, 6, 6, 8, 8, 10, 10];
+
     public static int Get4x4WideCount(this Av1BlockSize blockSize) => SizeWide[(int)blockSize];
 
     public static int Get4x4HighCount(this Av1BlockSize blockSize) => SizeHigh[(int)blockSize];
@@ -82,13 +85,19 @@ public static int Get4x4HeightLog2(this Av1BlockSize blockSize)
     /// Returns the block size of a sub sampled block.
     /// </summary>
     public static Av1BlockSize GetSubsampled(this Av1BlockSize blockSize, bool subX, bool subY)
+        => GetSubsampled(blockSize, subX ? 1 : 0, subY ? 1 : 0);
+
+    /// <summary>
+    /// Returns the block size of a sub sampled block.
+    /// </summary>
+    public static Av1BlockSize GetSubsampled(this Av1BlockSize blockSize, int subX, int subY)
     {
         if (blockSize == Av1BlockSize.Invalid)
         {
             return Av1BlockSize.Invalid;
         }
 
-        return SubSampled[(int)blockSize][subX ? 1 : 0][subY ? 1 : 0];
+        return SubSampled[(int)blockSize][subX][subY];
     }
 
     public static Av1TransformSize GetMaxUvTransformSize(this Av1BlockSize blockSize, bool subX, bool subY)
@@ -115,4 +124,7 @@ public static Av1TransformSize GetMaxUvTransformSize(this Av1BlockSize blockSize
     /// </summary>
     public static Av1TransformSize GetMaximumTransformSize(this Av1BlockSize blockSize)
         => MaxTransformSize[(int)blockSize];
+
+    public static int GetPelsLog2Count(this Av1BlockSize blockSize)
+        => PelsLog2Count[(int)blockSize];
 }

src/ImageSharp/Formats/Heif/Av1/Av1Constants.cs

@@ -138,4 +138,6 @@ internal static class Av1Constants
     /// Maximum transform size categories.
     /// </summary>
     public const int MaxTransformCategories = 4;
+
+    public const int CoefficientContextCount = 6;
 }

src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs

@@ -1095,7 +1095,6 @@ frameInfo.ReferenceFrameIndex[i] < ((1 << idLength) + (frameInfo.CurrentFrameId
         ReadFrameDeltaLoopFilterParameters(ref reader, frameInfo);
 
         // SetupSegmentationDequantization();
-        Av1MainParseContext mainParseContext = new();
         if (frameInfo.PrimaryReferenceFrame == Av1Constants.PrimaryReferenceFrameNone)
         {
             // ResetParseContext(mainParseContext, frameInfo.QuantizationParameters.BaseQIndex);

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1FrameBuffer.cs

@@ -150,6 +150,15 @@ public void SetTransformUv(int index, Av1TransformInfo transformInfo)
         span[index] = transformInfo;
     }
 
+    public Span<int> GetCoefficients(int plane) =>
+        plane switch
+        {
+            0 => (Span<int>)this.coefficientsY,
+            2 => (Span<int>)this.coefficientsY,
+            3 => (Span<int>)this.coefficientsY,
+            _ => null,
+        };
+
     public Span<int> GetCoefficientsY(Point index)
     {
         Span<int> span = this.coefficientsY;

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1ParseAboveNeighbor4x4Context.cs

@@ -46,6 +46,8 @@ public Av1ParseAboveNeighbor4x4Context(int planesCount, int modeInfoColumnCount)
 
     public int[] AboveTransformWidth => this.aboveTransformWidth;
 
+    public int[] GetContext(int plane) => this.aboveContext[plane];
+
     public void Clear(ObuSequenceHeader sequenceHeader)
     {
         int planeCount = sequenceHeader.ColorConfig.ChannelCount;

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1ParseLeftNeighbor4x4Context.cs

@@ -91,4 +91,6 @@ public void UpdateTransformation(Point modeInfoLocation, Av1SuperblockInfo super
 
     internal void ClearContext(int plane, int offset, int length)
         => Array.Fill(this.leftContext[plane], 0, offset, length);
+
+    internal int[] GetContext(int plane) => this.leftContext[plane];
 }

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1PartitionInfo.cs

@@ -50,6 +50,10 @@ public Av1PartitionInfo(Av1BlockModeInfo modeInfo, Av1SuperblockInfo superblockI
 
     public int[] ReferenceFrame { get; set; }
 
+    public int ModeBlockToRightEdge => this.modeBlockToRightEdge;
+
+    public int ModeBlockToBottomEdge => this.modeBlockToBottomEdge;
+
     public void ComputeBoundaryOffsets(ObuFrameHeader frameInfo, Av1TileInfo tileInfo)
     {
         Av1BlockSize blockSize = this.ModeInfo.BlockSize;

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TransformBlockContext.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Heif.Av1.Symbol;
+
+internal class Av1TransformBlockContext
+{
+    public int DcSignContext { get; set; }
+
+    public int SkipContext { get; set; }
+}

src/ImageSharp/Formats/Heif/Av1/Transform/Av1TransformSizeExtensions.cs

@@ -36,6 +36,29 @@ internal static class Av1TransformSizeExtensions
     // Transform block height in unit
     private static readonly int[] HighUnit = [1, 2, 4, 8, 16, 2, 1, 4, 2, 8, 4, 16, 8, 4, 1, 8, 2, 16, 4];
 
+    // Transform size conversion into Block Size
+    private static readonly Av1BlockSize[] BlockSize = [
+        Av1BlockSize.Block4x4, // TX_4X4
+        Av1BlockSize.Block8x8, // TX_8X8
+        Av1BlockSize.Block16x16, // TX_16X16
+        Av1BlockSize.Block32x32, // TX_32X32
+        Av1BlockSize.Block64x64, // TX_64X64
+        Av1BlockSize.Block4x8, // TX_4X8
+        Av1BlockSize.Block8x4, // TX_8X4
+        Av1BlockSize.Block8x16, // TX_8X16
+        Av1BlockSize.Block16x8, // TX_16X8
+        Av1BlockSize.Block16x32, // TX_16X32
+        Av1BlockSize.Block32x16, // TX_32X16
+        Av1BlockSize.Block32x64, // TX_32X64
+        Av1BlockSize.Block64x32, // TX_64X32
+        Av1BlockSize.Block4x16, // TX_4X16
+        Av1BlockSize.Block16x4, // TX_16X4
+        Av1BlockSize.Block8x32, // TX_8X32
+        Av1BlockSize.Block32x8, // TX_32X8
+        Av1BlockSize.Block16x64, // TX_16X64
+        Av1BlockSize.Block64x16, // TX_64X16
+    ];
+
     public static int GetScale(this Av1TransformSize size)
     {
         int pels = Size2d[(int)size];
@@ -55,4 +78,6 @@ public static int GetScale(this Av1TransformSize size)
     public static int Get4x4HighCount(this Av1TransformSize size) => HighUnit[(int)size];
 
     public static Av1TransformSize GetSubSize(this Av1TransformSize size) => SubTransformSize[(int)size];
+
+    public static Av1BlockSize GetBlockSize(this Av1TransformSize transformSize) => (Av1BlockSize)BlockSize[(int)transformSize];
 }