Round trip empty Coefficients buffer

src/ImageSharp/Formats/Heif/Av1/Entropy/Av1SymbolEncoder.cs

@@ -128,12 +128,12 @@ internal class Av1SymbolEncoder : IDisposable
         if (eob_offset_bits > 0)
         {
             int eob_shift = eob_offset_bits - 1;
-            int bit = Math.Max(1, eob_extra & 1 << eob_shift);
+            int bit = (eob_extra & (1 << eob_shift)) != 0 ? 1 : 0;
             w.WriteSymbol(bit, this.endOfBlockExtra[(int)transformSizeContext][(int)componentType][endOfBlockPosition]);
             for (int i = 1; i < eob_offset_bits; i++)
             {
                 eob_shift = eob_offset_bits - 1 - i;
-                bit = Math.Max(1, eob_extra & 1 << eob_shift);
+                bit = (eob_extra & (1 << eob_shift)) != 0 ? 1 : 0;
                 w.WriteLiteral((uint)bit, 1);
             }
         }

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1LevelBuffer.cs

@@ -50,7 +50,7 @@ internal sealed class Av1LevelBuffer : IDisposable
         ObjectDisposedException.ThrowIf(this.memory == null, this);
         ArgumentOutOfRangeException.ThrowIfLessThan(y, -Av1Constants.TransformPadTop);
         int row = y + Av1Constants.TransformPadTop;
-        return this.memory.Memory.Span.Slice(row * this.Stride, this.Size.Width);
+        return this.memory.Memory.Span.Slice(row * this.Stride, this.Size.Width + Av1Constants.TransformPadHorizontal);
     }
 
     public void Dispose()

tests/ImageSharp.Tests/Formats/Heif/Av1/Av1CoefficientsEntropyTests.cs

@@ -39,6 +39,7 @@ public class Av1CoefficientsEntropyTests
         Configuration configuration = Configuration.Default;
         Av1SymbolEncoder encoder = new(configuration, 100 / 8, BaseQIndex);
         Span<int> coefficientsBuffer = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];
+        Span<int> expected = new int[16];
         Span<int> actuals = new int[16];
 
         // Act
@@ -51,7 +52,7 @@ public class Av1CoefficientsEntropyTests
         decoder.ReadCoefficients(modeInfo, new Point(0, 0), aboveContexts, leftContexts, 0, 0, 0, 1, 1, transformBlockContext, transformSize, false, true, transformInfo, 0, 0, actuals);
 
         // Assert
-        Assert.Equal(coefficientsBuffer, actuals);
+        Assert.Equal(expected, actuals);
     }
 
 }