Add high-bit-depth AV1 reconstruction

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

@@ -47,4 +47,23 @@ internal class Av1InverseTransformer
         Av1InverseTransformerFactory.InverseTransformAdd(
             coefficientsBuffer, reconstructionBufferRead, reconstructionReadStride, reconstructionBufferWrite, reconstructionWriteStride, transformFunctionParameters);
     }
+
+    /// <summary>
+    /// AV1: 7.11.2 Reconstruct.
+    /// </summary>
+    public static void ReconstructHighBitDepth(Span<int> coefficientsBuffer, Span<short> reconstructionBuffer, int reconstructionStride, Av1TransformSize transformSize, Av1TransformType transformType, int plane, int numberOfCoefficients, bool isLossless, Av1BitDepth bitDepth)
+    {
+        Av1TransformFunctionParameters transformFunctionParameters = new()
+        {
+            TransformType = transformType,
+            TransformSize = transformSize,
+            EndOfBuffer = numberOfCoefficients,
+            IsLossless = isLossless,
+            BitDepth = bitDepth.GetBitCount(),
+            Is16BitPipeline = true
+        };
+
+        Av1InverseTransformerFactory.InverseTransformAdd(
+            coefficientsBuffer, reconstructionBuffer, reconstructionStride, reconstructionBuffer, reconstructionStride, transformFunctionParameters);
+    }
 }

tests/ImageSharp.Tests/Formats/Heif/Av1/Av1InverseTransformTests.cs

@@ -267,6 +267,56 @@ public class Av1InverseTransformTests
         Assert.Equal(expected.Select(value => (byte)value), actual);
     }
 
+    [Theory]
+    [InlineData((int)Av1BitDepth.TenBit, 1023)]
+    [InlineData((int)Av1BitDepth.TwelveBit, 4095)]
+    public void HighBitDepthReconstructionClipsPositiveValues(int bitDepthIndex, short maximum)
+    {
+        const int width = 4;
+        int[] coefficients = new int[width * width];
+        coefficients[0] = 64;
+        short[] reconstruction = new short[width * width];
+        Array.Fill(reconstruction, (short)(maximum - 1));
+
+        Av1InverseTransformer.ReconstructHighBitDepth(
+            coefficients,
+            reconstruction,
+            width,
+            Av1TransformSize.Size4x4,
+            Av1TransformType.DctDct,
+            0,
+            1,
+            false,
+            (Av1BitDepth)bitDepthIndex);
+
+        Assert.All(reconstruction, value => Assert.Equal(maximum, value));
+    }
+
+    [Theory]
+    [InlineData((int)Av1BitDepth.TenBit)]
+    [InlineData((int)Av1BitDepth.TwelveBit)]
+    public void HighBitDepthReconstructionClipsNegativeValues(int bitDepthIndex)
+    {
+        const int width = 4;
+        int[] coefficients = new int[width * width];
+        coefficients[0] = -64;
+        short[] reconstruction = new short[width * width];
+        Array.Fill(reconstruction, (short)1);
+
+        Av1InverseTransformer.ReconstructHighBitDepth(
+            coefficients,
+            reconstruction,
+            width,
+            Av1TransformSize.Size4x4,
+            Av1TransformType.DctDct,
+            0,
+            1,
+            false,
+            (Av1BitDepth)bitDepthIndex);
+
+        Assert.All(reconstruction, value => Assert.Equal((short)0, value));
+    }
+
     private static void AssertAccuracy1d(
         Av1TransformType transformType,
         Av1TransformSize transformSize,