diff --git a/src/ImageSharp/Formats/Heif/Av1/Av1BlockSize.cs b/src/ImageSharp/Formats/Heif/Av1/Av1BlockSize.cs
index f043208e98..6eca5bc638 100644
--- a/src/ImageSharp/Formats/Heif/Av1/Av1BlockSize.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/Av1BlockSize.cs
@@ -32,13 +32,3 @@ internal enum Av1BlockSize
     BlockInvalid = 255,
     BlockLargest = BlockSizeS - 1,
 }
-
-internal static class Av1BlockSizeExtensions
-{
-    private static readonly int[] SizeWide = { 1, 1, 2, 2, 2, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 1, 4, 2, 8, 4, 16 };
-    private static readonly int[] SizeHigh = { 1, 2, 1, 2, 4, 2, 4, 8, 4, 8, 16, 8, 16, 32, 16, 32, 4, 1, 8, 2, 16, 4 };
-
-    public static int Get4x4WideCount(this Av1BlockSize blockSize) => SizeWide[(int)blockSize];
-
-    public static int Get4x4HighCount(this Av1BlockSize blockSize) => SizeHigh[(int)blockSize];
-}
diff --git a/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs b/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs
new file mode 100644
index 0000000000..16190dd6b2
--- /dev/null
+++ b/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs
@@ -0,0 +1,14 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Formats.Heif.Av1;
+
+internal static class Av1BlockSizeExtensions
+{
+    private static readonly int[] SizeWide = { 1, 1, 2, 2, 2, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 1, 4, 2, 8, 4, 16 };
+    private static readonly int[] SizeHigh = { 1, 2, 1, 2, 4, 2, 4, 8, 4, 8, 16, 8, 16, 32, 16, 32, 4, 1, 8, 2, 16, 4 };
+
+    public static int Get4x4WideCount(this Av1BlockSize blockSize) => SizeWide[(int)blockSize];
+
+    public static int Get4x4HighCount(this Av1BlockSize blockSize) => SizeHigh[(int)blockSize];
+}
diff --git a/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs b/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs
index c8bec52428..8841697388 100644
--- a/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs
@@ -5,7 +5,7 @@ using SixLabors.ImageSharp.Formats.Heif.Av1.OpenBitstreamUnit;
 
 namespace SixLabors.ImageSharp.Formats.Heif.Av1;
 
-internal class Av1Decoder
+internal class Av1Decoder : IAv1TileDecoder
 {
     public Av1Decoder()
     {
@@ -32,20 +32,19 @@ internal class Av1Decoder
         ObuReader.Read(ref reader, buffer.Length, this, false);
     }
 
-    internal void DecodeTile(ref Av1BitStreamReader reader, int tileNum)
+    public void DecodeTile(ref Av1BitStreamReader reader, int tileNum)
     {
         // TODO: Implement
     }
 
-    internal void DecodeBlock(Av1BlockModeInfo blockMode, int rowIndex, int columnIndex)
+    public void FinishDecodeTiles(ref Av1BitStreamReader reader, bool doCdef, bool doLoopRestoration)
     {
-        int block4x4Width = blockMode.BlockSize.Get4x4WideCount();
-        int block4x4Height = blockMode.BlockSize.Get4x4HighCount();
-
+        // TODO: Implement
     }
 
-    internal void FinishDecodeTiles(ref Av1BitStreamReader reader, bool doCdef, bool doLoopRestoration)
+    private static void DecodeBlock(Av1BlockModeInfo blockMode, int rowIndex, int columnIndex)
     {
-        // TODO: Implement
+        int block4x4Width = blockMode.BlockSize.Get4x4WideCount();
+        int block4x4Height = blockMode.BlockSize.Get4x4HighCount();
     }
 }