Apply AV1 motion-cost refresh cadence during tile encoding

HEIF_IMPLEMENTATION_PLAN.md

@@ -65,8 +65,17 @@ verification before advancing. The following dependency result does not close th
   `Av1EncoderBlockWorkspace` appends exactly 131,072 integer elements (512 KiB) only for inter workers.
   The sequence owner retains this storage across frames; still-image workers retain their previous allocation.
   Native evidence: `block.h:763-793`, `encoder_alloc.h:57-75`, `encodemv.c:125-250`, `rd.c:687-705`,
-  and `encodeframe_utils.c:1663-1675`. Per-superblock refresh is connected; speed-dependent row/set refresh
+  and `encodeframe_utils.c:1663-1675`. Motion-cost refresh now follows the configured superblock, row, or
-  remains to be integrated with the new configuration controller.
+  evenly spaced row-set cadence. Levels 3 and above use rows; levels 5 and above below 720p use row sets.
+  Evidence: `speed_features.c:1002,1315`, `encodeframe_utils.c:1556-1589,1628-1630,1663-1675`.
+  `Av1MotionSearchSettings` resolves the policy and `Av1TileEncoder.ProcessTiles` applies it to the actual
+  serial traversal, initializing each tile even when CDF adaptation is disabled. The frame-height rounding
+  yields evenly distributed update rows for both 64- and 128-sample superblocks, including short final tiles.
+  Release .NET 11 passed with zero errors and 1,009 existing warnings after the final edit. VSTest passed
+  324/324 focused frame, motion-policy, and superblock cases. Optimized native decoding matched all 39
+  compact streams (86,859 samples), plus three 129x273 multi-row streams (477,243 samples): maximum error
+  zero, differing samples zero, samples exceeding one zero. These checks do not establish encoder parity
+  or a measured performance improvement. Mode and coefficient cost-refresh lifecycles remain unresolved.
 - Inter-mode rate calculation now applies the missing rounded 108/128 weight to motion-vector rate alone.
   Evidence: `mcomp.c:306-312`, `rd.h:46`, `motion_search_facade.c:535-542`; managed owning method is
   `Av1IntraSuperblockEncoder.ReferenceModeDecision.GetInterModeRate`. Search still requires the separate
@@ -272,7 +281,7 @@ verification before advancing. The following dependency result does not close th
   The fixture now supplies an explicit entropy history favoring GLOBALMV and checks its cost against every
   competing mode; all preexisting expected skip/rate/distortion/coefficient/pixel assertions remain intact.
 - This remains the same active production milestone. Scaled references, production temporal analysis,
-  broader block/reference support, complete mode pruning and ordering, and speed-dependent entropy-cost refresh
+  broader block/reference support, complete mode pruning and ordering, and mode/coefficient cost refresh
   remain open. Still-image and intra/global-motion Effort policies are not migrated. The production decoder
   comparisons establish same-bitstream equality only, not separate-encoder parity, performance, or codec completion.
 

src/ImageSharp/Formats/Heif/Av1/Motion/Av1MotionSearchSettings.cs

@@ -94,6 +94,7 @@ internal readonly struct Av1MotionSearchSettings
                 this.SecondCandidateSelection = CandidateSelection.FirstOnly;
                 this.MeshPruningLevel = 1;
                 this.AllowIntraBlockCopy = false;
+                this.MotionCostUpdate = CostUpdateFrequency.SuperblockRow;
             }
 
             if (speed >= HeifEncodingSpeed.Level4)
@@ -140,6 +141,7 @@ internal readonly struct Av1MotionSearchSettings
                 if (!is720pOrLarger)
                 {
                     this.DownsampledSadLevel = 1;
+                    this.MotionCostUpdate = CostUpdateFrequency.SuperblockRowSet;
                 }
             }
 
@@ -185,6 +187,27 @@ internal readonly struct Av1MotionSearchSettings
         }
     }
 
+    /// <summary>
+    /// The serial tile traversal boundaries at which motion costs are refreshed.
+    /// </summary>
+    public enum CostUpdateFrequency
+    {
+        /// <summary>
+        /// Refresh before each superblock.
+        /// </summary>
+        Superblock,
+
+        /// <summary>
+        /// Refresh at the first superblock of each tile row.
+        /// </summary>
+        SuperblockRow,
+
+        /// <summary>
+        /// Refresh at evenly spaced sets of superblock rows within a tile.
+        /// </summary>
+        SuperblockRowSet
+    }
+
     /// <summary>
     /// The full-pixel search pattern.
     /// </summary>
@@ -304,6 +327,11 @@ internal readonly struct Av1MotionSearchSettings
         FirstOnly
     }
 
+    /// <summary>
+    /// Gets the frequency at which selected motion symbols refresh the search cost tables.
+    /// </summary>
+    public CostUpdateFrequency MotionCostUpdate { get; }
+
     /// <summary>
     /// Gets the adaptation level for the initial full-pixel step.
     /// </summary>

src/ImageSharp/Formats/Heif/Av1/Pipeline/Av1TileEncoder.cs

@@ -327,6 +327,7 @@ internal readonly struct Av1TileEncoder : IAv1TileWriter
         ObuTileGroupHeader tileLayout = frameHeader.TilesInfo;
         Span<int> tileDataOffsets = picture.TileDataOffsets.Span;
         Span<int> tileDataLengths = picture.TileDataLengths.Span;
+        Av1MotionSearchSettings.CostUpdateFrequency motionCostUpdate = picture.Parent.MotionSearchSettings.MotionCostUpdate;
         if (!TSymbolOperation.WritesOutput && frameHeader.AllowIntraBlockCopy)
         {
             // Hash the visible source once before reconstruction begins so candidate discovery never depends
@@ -348,6 +349,17 @@ internal readonly struct Av1TileEncoder : IAv1TileWriter
                 // advances the output offset; the analysis operation does not touch range-coder state.
                 writer.Reset(tileDataEnd);
 
+                int motionCostRowInterval = 1;
+                if (motionCostUpdate == Av1MotionSearchSettings.CostUpdateFrequency.SuperblockRowSet)
+                {
+                    // Target one update per 256 luma rows, then distribute those updates evenly over the
+                    // tile's superblock rows. Two rounded divisions keep short final tiles evenly spaced.
+                    int tileHeight = (tile.ModeInfoRowEnd - tile.ModeInfoRowStart) << Av1Constants.ModeInfoSizeLog2;
+                    int updateCount = (tileHeight + 255) / 256;
+                    int updateSpan = updateCount << sequenceHeader.SuperblockSizeLog2;
+                    motionCostRowInterval = (tileHeight + updateSpan - 1) / updateSpan;
+                }
+
                 Point firstModeInfoPosition = new(tile.ModeInfoColumnStart, tile.ModeInfoRowStart);
                 entropyContext.MacroBlockModeInfo = picture.GetMacroBlockModeInfo(firstModeInfoPosition);
                 for (int modeInfoRow = tile.ModeInfoRowStart;
@@ -379,10 +391,17 @@ internal readonly struct Av1TileEncoder : IAv1TileWriter
                         }
                         else
                         {
-                            if (!frameHeader.IsIntra)
+                            bool firstColumn = modeInfoColumn == tile.ModeInfoColumnStart;
+                            bool firstSuperblock = firstColumn && modeInfoRow == tile.ModeInfoRowStart;
+                            int tileSuperblockRow = (modeInfoRow - tile.ModeInfoRowStart) >> superblockShift;
+                            bool refreshMotionCosts = motionCostUpdate == Av1MotionSearchSettings.CostUpdateFrequency.Superblock ||
+                                (firstColumn && (tileSuperblockRow % motionCostRowInterval) == 0);
+
+                            if (!frameHeader.IsIntra && (firstSuperblock || (!frameHeader.DisableCdfUpdate && refreshMotionCosts)))
                             {
-                                // Candidates within a superblock share one entropy snapshot. Updating while
+                                // Initialize from each tile's starting CDF even when adaptation is disabled.
-                                // trying partitions would make the search depend on discarded alternatives.
+                                // Later updates consume only preceding selected blocks at the configured boundary;
+                                // all candidate trials between boundaries share the same cost snapshot.
                                 writer.FillMotionVectorCosts(blockWorkspace.GetMotionVectorCosts(frameHeader.MotionVectorPrecision));
                             }
 

tests/ImageSharp.Tests/Formats/Heif/Av1/Av1EncoderFrameTests.cs

@@ -392,26 +392,46 @@ public class Av1EncoderFrameTests
         int colorFormatValue,
         int effort,
         HeifEncodingSpeed speed)
+        => VerifySequenceEncoderColorPlanes(bitDepthValue, colorFormatValue, effort, speed, 23, 19);
+
+    [Theory]
+    [InlineData(HeifEncodingSpeed.Level0)]
+    [InlineData(HeifEncodingSpeed.Level3)]
+    [InlineData(HeifEncodingSpeed.Level5)]
+    public void SequenceEncoderPreservesNativeColorPlanesAcrossMotionCostRefreshRows(HeifEncodingSpeed speed)
+        => VerifySequenceEncoderColorPlanes(EightBit, Yuv420, 8, speed, 129, 273);
+
+    private static void VerifySequenceEncoderColorPlanes(
+        int bitDepthValue,
+        int colorFormatValue,
+        int effort,
+        HeifEncodingSpeed speed,
+        int width,
+        int height)
     {
-        const int Width = 23;
+        // A 129x273 frame crosses both columns and uneven row sets of 64- or 128-sample superblocks.
-        const int Height = 19;
+        // The compact fixture retains its odd visible edges and all precision/subsampling combinations.
         const int QIndex = 17;
         const int ByteToUInt16Scale = ushort.MaxValue / byte.MaxValue;
         Av1BitDepth bitDepth = (Av1BitDepth)bitDepthValue;
         Av1ColorFormat colorFormat = (Av1ColorFormat)colorFormatValue;
         ObuColorConfig colorConfig = CreateColorConfig(bitDepth, colorFormat);
         ReadOnlySpan<int> period = [0, 28, 40, 28, 0, -28, -40, -12];
-        using Image<Rgb48> source = new(Width, Height);
+        using Image<Rgb48> source = new(width, height);
         using Av1FrameEncoder.SequenceEncoder encoder = Av1FrameEncoder.CreateColorSequenceEncoder(
             Configuration.Default,
-            Width,
+            width,
-            Height,
+            height,
             colorConfig,
             QIndex,
             effort,
             speed);
 
-        string outputDirectory = TestEnvironment.CreateOutputDirectory("Heif", "Av1", nameof(this.SequenceEncoderPreservesNativeColorPlanesWithSubpixelMotion));
+        string outputFolder = width == 23 ? nameof(SequenceEncoderPreservesNativeColorPlanesWithSubpixelMotion)
+            : nameof(SequenceEncoderPreservesNativeColorPlanesAcrossMotionCostRefreshRows);
+
+        string outputDirectory = TestEnvironment.CreateOutputDirectory("Heif", "Av1", outputFolder);
+
         string outputName = $"{bitDepth.GetBitCount()}-{colorFormat}-effort{effort}-speed{(int)speed}";
         using FileStream output = File.Create(Path.Combine(outputDirectory, outputName + ".obu"));
         using BinaryWriter rawOutput = new(File.Create(Path.Combine(outputDirectory, outputName + ".managed.yuv")));
@@ -422,13 +442,13 @@ public class Av1EncoderFrameTests
             // The second source translates all three channels by one luma sample on each axis. Chroma is
             // converted independently by the production converter, so 4:2:0 and 4:2:2 cannot hide behind
             // constant neutral planes. Odd dimensions also exercise each plane's visible-edge clipping.
-            for (int y = 0; y < Height; y++)
+            for (int y = 0; y < height; y++)
             {
                 Span<Rgb48> row = source.Frames.RootFrame.PixelBuffer.DangerousGetRowSpan(y);
-                int referenceY = Math.Min(y + frameIndex, Height - 1);
+                int referenceY = Math.Min(y + frameIndex, height - 1);
-                for (int x = 0; x < Width; x++)
+                for (int x = 0; x < width; x++)
                 {
-                    int referenceX = Math.Min(x + frameIndex, Width - 1);
+                    int referenceX = Math.Min(x + frameIndex, width - 1);
                     row[x] = new Rgb48(
                         (ushort)((128 + period[referenceX % period.Length]) * ByteToUInt16Scale),
                         (ushort)((128 + period[referenceY % period.Length]) * ByteToUInt16Scale),
@@ -451,8 +471,8 @@ public class Av1EncoderFrameTests
             decoder.DecodeSequenceReference(sample.ToArray(), null, null);
             Assert.True(Assert.IsType<ObuSequenceHeader>(decoder.SequenceHeader).EnableIntraEdgeFilter);
             Av1FrameBuffer<byte> decoded = Assert.IsType<Av1FrameBuffer<byte>>(decoder.FrameBuffer);
-            Assert.Equal(Width, decoded.Width);
+            Assert.Equal(width, decoded.Width);
-            Assert.Equal(Height, decoded.Height);
+            Assert.Equal(height, decoded.Height);
             Assert.Equal(bitDepth, decoded.BitDepth);
             Av1FrameInfo decodedFrameInfo = Assert.IsType<Av1FrameInfo>(decoder.FrameInfo);
             foreach (Av1BlockModeInfo mode in decodedFrameInfo.GetModeInfos(Point.Empty, decodedFrameInfo.GetModeInfoCount(Point.Empty)))
@@ -470,7 +490,7 @@ public class Av1EncoderFrameTests
                 Av1Plane plane = (Av1Plane)planeIndex;
                 int subsamplingX = plane == Av1Plane.Y || !colorConfig.SubSamplingX ? 0 : 1;
                 int subsamplingY = plane == Av1Plane.Y || !colorConfig.SubSamplingY ? 0 : 1;
-                int planeHeight = (Height + subsamplingY) >> subsamplingY;
+                int planeHeight = (height + subsamplingY) >> subsamplingY;
                 if (bitDepth == Av1BitDepth.EightBit)
                 {
                     Buffer2DRegion<byte> planeSamples = decoded.DeriveBlockPointer(plane, subsamplingX, subsamplingY);