Rename ChannelCount property to PlaneCount

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

@@ -7,8 +7,15 @@ internal class ObuColorConfig
 {
     public bool IsColorDescriptionPresent { get; set; }
 
-    public int ChannelCount { get; set; }
-
+    /// <summary>
+    /// Gets or sets the number of color channels in this image.
+    /// </summary>
+    public int PlaneCount { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the image has a single greyscale plane, will have
+    /// <see cref="Av1Constants.MaxPlanes"/> color planes otherwise.
+    /// </summary>
     public bool IsMonochrome { get; set; }
 
     public ObuColorPrimaries ColorPrimaries { get; set; }

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

@@ -465,7 +465,7 @@ internal class ObuReader
             colorConfig.IsMonochrome = reader.ReadBoolean();
         }
 
-        colorConfig.ChannelCount = colorConfig.IsMonochrome ? 1 : 3;
+        colorConfig.PlaneCount = colorConfig.IsMonochrome ? 1 : Av1Constants.MaxPlanes;
         colorConfig.IsColorDescriptionPresent = reader.ReadBoolean();
         colorConfig.ColorPrimaries = ObuColorPrimaries.Unspecified;
         colorConfig.TransferCharacteristics = ObuTransferCharacteristics.Unspecified;
@@ -1191,7 +1191,7 @@ internal class ObuReader
     /// </summary>
     private void ReadFrameHeader(ref Av1BitStreamReader reader, ObuHeader header, bool trailingBit)
     {
-        int planeCount = this.SequenceHeader!.ColorConfig.IsMonochrome ? 1 : 3;
+        int planeCount = this.SequenceHeader!.ColorConfig.PlaneCount;
         int startBitPosition = reader.BitPosition;
         this.ReadUncompressedFrameHeader(ref reader, header, planeCount);
         if (trailingBit)

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

@@ -112,6 +112,7 @@ internal class ObuWriter
             writer.WriteBoolean(colorConfig.IsMonochrome);
         }
 
+        colorConfig.PlaneCount = colorConfig.IsMonochrome ? 1 : Av1Constants.MaxPlanes;
         writer.WriteBoolean(false); // colorConfig.IsColorDescriptionPresent
         if (colorConfig.IsMonochrome)
         {

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

@@ -50,7 +50,7 @@ internal class Av1ParseAboveNeighbor4x4Context
 
     public void Clear(ObuSequenceHeader sequenceHeader, int modeInfoColumnStart, int modeInfoColumnEnd)
     {
-        int planeCount = sequenceHeader.ColorConfig.ChannelCount;
+        int planeCount = sequenceHeader.ColorConfig.PlaneCount;
         int width = modeInfoColumnEnd - modeInfoColumnStart;
         Array.Fill(this.AboveTransformWidth, Av1TransformSize.Size64x64.GetWidth(), 0, width);
         Array.Fill(this.AbovePartitionWidth, 0, 0, width);

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

@@ -50,7 +50,7 @@ internal class Av1ParseLeftNeighbor4x4Context
     public void Clear(ObuSequenceHeader sequenceHeader)
     {
         int blockCount = sequenceHeader.SuperblockModeInfoSize;
-        int planeCount = sequenceHeader.ColorConfig.ChannelCount;
+        int planeCount = sequenceHeader.ColorConfig.PlaneCount;
         int neighbor4x4Count = sequenceHeader.SuperblockModeInfoSize;
         Array.Fill(this.LeftTransformHeight, Av1TransformSize.Size64x64.GetHeight(), 0, blockCount);
         Array.Fill(this.LeftPartitionHeight, 0, 0, blockCount);

src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileDecoder.cs

@@ -52,7 +52,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
 
         // reallocate_parse_context_memory
         // Hard code number of threads to 1 for now.
-        int planesCount = sequenceHeader.ColorConfig.IsMonochrome ? 1 : Av1Constants.MaxPlanes;
+        int planesCount = sequenceHeader.ColorConfig.PlaneCount;
         int superblockColumnCount =
             Av1Math.AlignPowerOf2(sequenceHeader.MaxFrameWidth, sequenceHeader.SuperblockSizeLog2) >> sequenceHeader.SuperblockSizeLog2;
         int modeInfoWideColumnCount = superblockColumnCount * sequenceHeader.SuperblockModeInfoSize;
@@ -84,7 +84,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
         int modeInfoRowEnd = this.FrameInfo.TilesInfo.TileRowStartModeInfo[tileRowIndex + 1];
         this.aboveNeighborContext.Clear(this.SequenceHeader, modeInfoColumnStart, modeInfoColumnEnd);
         this.ClearLoopFilterDelta();
-        int planesCount = this.SequenceHeader.ColorConfig.ChannelCount;
+        int planesCount = this.SequenceHeader.ColorConfig.PlaneCount;
 
         // Default initialization of Wiener and SGR Filter.
         this.referenceSgrXqd = new int[planesCount][];
@@ -138,7 +138,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
 
     private void ReadLoopRestoration(Point modeInfoLocation, Av1BlockSize superBlockSize)
     {
-        int planesCount = this.SequenceHeader.ColorConfig.ChannelCount;
+        int planesCount = this.SequenceHeader.ColorConfig.PlaneCount;
         for (int plane = 0; plane < planesCount; plane++)
         {
             if (this.FrameInfo.LoopRestorationParameters[plane].Type != ObuRestorationType.None)
@@ -290,7 +290,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
         int columnIndex = modeInfoLocation.X;
         int block4x4Width = blockSize.Get4x4WideCount();
         int block4x4Height = blockSize.Get4x4HighCount();
-        int planesCount = this.SequenceHeader.ColorConfig.ChannelCount;
+        int planesCount = this.SequenceHeader.ColorConfig.PlaneCount;
         Point superblockLocation = superblockInfo.Position * this.SequenceHeader.SuperblockModeInfoSize;
         Point locationInSuperblock = new Point(modeInfoLocation.X - superblockLocation.X, modeInfoLocation.Y - superblockLocation.Y);
         Av1BlockModeInfo blockModeInfo = new(planesCount, blockSize, locationInSuperblock);
@@ -341,7 +341,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
 
     private void ResetSkipContext(Av1PartitionInfo partitionInfo)
     {
-        int planesCount = this.SequenceHeader.ColorConfig.IsMonochrome ? 1 : 3;
+        int planesCount = this.SequenceHeader.ColorConfig.PlaneCount;
         for (int i = 0; i < planesCount; i++)
         {
             bool subX = i > 0 && this.SequenceHeader.ColorConfig.SubSamplingX;
@@ -368,7 +368,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
         int modeUnitBlocksHigh = maxUnitSize.GetHeight() >> 2;
         modeUnitBlocksWide = Math.Min(maxBlocksWide, modeUnitBlocksWide);
         modeUnitBlocksHigh = Math.Min(maxBlocksHigh, modeUnitBlocksHigh);
-        int planeCount = this.SequenceHeader.ColorConfig.ChannelCount;
+        int planeCount = this.SequenceHeader.ColorConfig.PlaneCount;
         bool isLossless = this.FrameInfo.LosslessArray[partitionInfo.ModeInfo.SegmentId];
         bool isLosslessBlock = isLossless && (blockSize >= Av1BlockSize.Block64x64) && (blockSize <= Av1BlockSize.Block128x128);
         int subSampling = (this.SequenceHeader.ColorConfig.SubSamplingX ? 1 : 0) + (this.SequenceHeader.ColorConfig.SubSamplingY ? 1 : 0);
@@ -1734,7 +1734,7 @@ internal class Av1TileDecoder : IAv1TileDecoder
             int frameLoopFilterCount = 1;
             if (this.FrameInfo.DeltaLoopFilterParameters.IsMulti)
             {
-                frameLoopFilterCount = this.SequenceHeader.ColorConfig.ChannelCount > 1 ? Av1Constants.FrameLoopFilterCount : Av1Constants.FrameLoopFilterCount - 2;
+                frameLoopFilterCount = this.SequenceHeader.ColorConfig.PlaneCount > 1 ? Av1Constants.FrameLoopFilterCount : Av1Constants.FrameLoopFilterCount - 2;
             }
 
             Span<int> currentDeltaLoopFilter = partitionInfo.SuperblockInfo.SuperblockDeltaLoopFilter;