diff --git a/HEIF_IMPLEMENTATION_PLAN.md b/HEIF_IMPLEMENTATION_PLAN.md index e5b5ed581f..eda710904c 100644 --- a/HEIF_IMPLEMENTATION_PLAN.md +++ b/HEIF_IMPLEMENTATION_PLAN.md @@ -831,7 +831,7 @@ Encoder verification contract: - [~] Encoder mode information now uses a frame-owned integer alias grid over a packed 8-byte value allocation, matching current libaom's `mi_grid_base` and `mi_alloc` relationship without a managed object or reference per 4x4 entry. Every coded 4x4 cell covered by square, rectangular, or clipped edge blocks maps to its owning allocation entry before context-dependent symbols are written. At 4K, mode values occupy about 4.0 MiB and the alias grid about 2.0 MiB. Packed syntax, relative neighbor lookup, full block mapping, writer traversal, entropy, and OBU coverage pass 1,947 of 1,947 direct net11 VSTest cases in Release; complete mode decision still remains. - [~] The final-block decision workspace uses one reusable 10.3 KiB ImageSharp allocator owner. It contains 1,024 explicitly packed 10-byte final-block entries and the 341 preorder partition bytes required by a complete 128x128-through-8x8 quadtree, replacing separate managed arrays. Initial rental is clean, and the explicit per-superblock reset clears the complete owner so pooled palette, quantizer, prediction, and partition bytes cannot leak into the next decision pass. Exact allocation, size, reset, return, repeated-run, writer, entropy, and OBU coverage pass 1,948 of 1,948 direct net11 VSTest cases in Release; complete mode decision still remains. - [~] Finalized transform coefficients and packed EOB/type state now use raster-ordered, per-superblock plane segments matching current libaom's coefficient-pool geometry. One ImageSharp allocator owner replaces libaom's separate coefficient, EOB, and entropy-context allocations while preserving the full 1024 luma and 256-per-chroma 4x4 state capacity of a 128x128 4:2:0 superblock. The transform-block boundary can populate the owner's quantized coefficient and state slices directly; mode-decision traversal still needs to select and invoke it. -- [~] Tile partition writing now follows current libaom's recursive `write_modes_sb` preorder traversal and `update_ext_partition_context` edge updates directly. Bottom-edge blocks use the horizontal-alike partition CDF and right-edge blocks use the vertical-alike CDF; byte-exact regressions cover both paths after the previous calls were found reversed. The obsolete SVT-derived global geometry catalog and its unimplemented lookup are removed; transform geometry is derived in libaom's bounded 64x64 residual order, fixed intra transform-size symbols use the reference depth and neighbor contexts, frame-edge and segmentation syntax use mode-information units, and 128x128 CDEF units use libaom's 0-to-3 indexing and first-block strength ownership. Writer, entropy, and OBU coverage passes 1,950 of 1,950 direct net11 VSTest cases in Release. Partition and mode analysis still need to populate these retained decisions; variable inter-transform syntax remains part of later inter-frame support. +- [~] Tile partition writing now follows current libaom's recursive `write_modes_sb` preorder traversal and `update_ext_partition_context` edge updates directly. Bottom-edge blocks use the horizontal-alike partition CDF and right-edge blocks use the vertical-alike CDF; byte-exact regressions cover both paths after the previous calls were found reversed. Lossless chroma-from-luma availability now uses the subsampled plane block size shared with the decoder instead of the lossy 32x32 limit, preserving the correct UV-mode alphabet for each segment. The obsolete SVT-derived global geometry catalog and its unimplemented lookup are removed; transform geometry is derived in libaom's bounded 64x64 residual order, fixed intra transform-size symbols use the reference depth and neighbor contexts, frame-edge and segmentation syntax use mode-information units, and 128x128 CDEF units use libaom's 0-to-3 indexing and first-block strength ownership. Writer, entropy, and OBU coverage passes 1,957 of 1,957 direct net11 VSTest cases in Release, with 20 of 20 focused encoder and decoder chroma-from-luma cases. Partition and mode analysis still need to populate these retained decisions; variable inter-transform syntax remains part of later inter-frame support. - [ ] Implement legal deblocking, CDEF, restoration, super-resolution, and film-grain signaling decisions. - [~] The coefficient symbol encoder now reuses tile-lifetime level and context workspaces instead of allocating per transform, defers both coefficient rents until the first nonzero transform block, and disposes all tile scratch independently from the detached encoded bytes. Its range coder matches current libaom's 64-bit coding window, bulk big-endian byte flush, and backward carry propagation while using one byte of allocator scratch per estimated output byte instead of the former 16-bit pre-carry storage. The reference-type symbol encoder is passed normally through tile traversal, and the operation boundary owns the allocator-backed item payload stream for exactly one synchronous encode. Every remaining encoder fragment must be audited before it becomes active. - [~] The planar conversion, residual construction, forward transform, and forward quantizer use descending SIMD dispatch: Vector512, Vector256, Vector128, then scalar. Residual construction matches current libaom's exact source-minus-prediction arithmetic for 8-bit and high-bit-depth planes, preserves independent row strides and unaligned starts, and writes directly into caller-owned signed-short storage without allocation. Apply the same rule to every later hot-path family. diff --git a/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs b/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs index 53993efd81..75005182cb 100644 --- a/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs +++ b/src/ImageSharp/Formats/Heif/Av1/Av1BlockSizeExtensions.cs @@ -179,6 +179,29 @@ internal static class Av1BlockSizeExtensions return SubSampled[(int)blockSize][subX][subY]; } + /// + /// Determines whether a luma block permits chroma-from-luma prediction. + /// + /// The luma block size. + /// Indicates whether the block belongs to a lossless segment. + /// Indicates horizontal chroma subsampling. + /// Indicates vertical chroma subsampling. + /// when chroma-from-luma prediction is permitted; otherwise, . + public static bool AllowsChromaFromLuma( + this Av1BlockSize blockSize, + bool isLossless, + bool subX, + bool subY) + { + if (isLossless) + { + // Lossless coding fixes the transform to 4x4, so the subsampled chroma block must have the same dimensions. + return blockSize.GetSubsampled(subX, subY) == Av1BlockSize.Block4x4; + } + + return blockSize.GetWidth() <= 32 && blockSize.GetHeight() <= 32; + } + /// /// Gets the maximum chroma transform size after applying plane subsampling and AV1 chroma transform limits. /// diff --git a/src/ImageSharp/Formats/Heif/Av1/Prediction/Av1PredictionDecoder.cs b/src/ImageSharp/Formats/Heif/Av1/Prediction/Av1PredictionDecoder.cs index 8c68bc172f..75ce908391 100644 --- a/src/ImageSharp/Formats/Heif/Av1/Prediction/Av1PredictionDecoder.cs +++ b/src/ImageSharp/Formats/Heif/Av1/Prediction/Av1PredictionDecoder.cs @@ -348,7 +348,13 @@ internal sealed class Av1PredictionDecoder where T : unmanaged, IBinaryInteger { Av1BlockModeInfo modeInfo = partitionInfo.ModeInfo; - bool isChromaFromLumaAllowedFlag = IsChromaFromLumaAllowedWithFrameHeader(ref partitionInfo, this.sequenceHeader.ColorConfig, this.frameHeader); + Av1BlockSize blockSize = modeInfo.BlockSize; + DebugGuard.MustBeLessThan((int)blockSize, (int)Av1BlockSize.AllSizes, nameof(blockSize)); + bool isChromaFromLumaAllowedFlag = blockSize.AllowsChromaFromLuma( + this.frameHeader.LosslessArray[modeInfo.SegmentId], + this.sequenceHeader.ColorConfig.SubSamplingX, + this.sequenceHeader.ColorConfig.SubSamplingY); + DebugGuard.IsTrue(isChromaFromLumaAllowedFlag, "Chroma from Luma should be allowed then computing it."); if (chromaFromLumaContext == null) @@ -379,32 +385,6 @@ internal sealed class Av1PredictionDecoder } } - /// - /// Determines whether chroma-from-luma prediction is permitted for the current block and frame state. - /// - /// The decoded partition and mode state for the containing block. - /// The sequence color configuration. - /// The decoded frame header. - /// when the block may use chroma-from-luma prediction; otherwise, . - private static bool IsChromaFromLumaAllowedWithFrameHeader(ref Av1PartitionInfo partitionInfo, ObuColorConfig colorConfig, ObuFrameHeader frameHeader) - { - Av1BlockModeInfo modeInfo = partitionInfo.ModeInfo; - Av1BlockSize blockSize = modeInfo.BlockSize; - DebugGuard.MustBeLessThan((int)blockSize, (int)Av1BlockSize.AllSizes, nameof(blockSize)); - if (frameHeader.LosslessArray[modeInfo.SegmentId]) - { - // In lossless, CfL is available when the partition size is equal to the - // transform size. - bool subX = colorConfig.SubSamplingX; - bool subY = colorConfig.SubSamplingY; - Av1BlockSize planeBlockSize = blockSize.GetSubsampled(subX, subY); - return planeBlockSize == Av1BlockSize.Block4x4; - } - - // Outside lossless mode, AV1 limits CfL to luma partitions no larger than 32 by 32. - return blockSize.GetWidth() <= 32 && blockSize.GetHeight() <= 32; - } - /// /// Converts the packed chroma-from-luma magnitude and joint sign into a signed Q3 scaling factor. /// diff --git a/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileWriter.cs b/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileWriter.cs index b7bae85c2f..5e8e73653e 100644 --- a/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileWriter.cs +++ b/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileWriter.cs @@ -708,12 +708,13 @@ internal partial class Av1TileWriter { EncodeIntraChromaMode( writer, + frm_hdr, + scs.SequenceHeader.ColorConfig, macroBlockModeInfo, ref blk_ptr, blockSize, intra_luma_mode, - intra_chroma_mode, - blockSize.GetWidth() <= 32 && blockSize.GetHeight() <= 32); + intra_chroma_mode); } } @@ -844,21 +845,28 @@ internal partial class Av1TileWriter /// Writes the chroma intra mode, chroma-from-luma alpha values, and directional angle adjustment for a block. /// /// The tile symbol encoder. + /// The current frame syntax and segment lossless state. + /// The sequence chroma subsampling configuration. /// The selected block modes. /// The encoder prediction-unit state. /// The luma block size. /// The selected luma prediction mode. /// The selected chroma prediction mode. - /// A value indicating whether chroma-from-luma mode is available. - private static void EncodeIntraChromaMode( + public static void EncodeIntraChromaMode( Av1SymbolEncoder writer, + ObuFrameHeader frameHeader, + ObuColorConfig colorConfig, Av1MacroBlockModeInfo macroBlockModeInfo, ref Av1EncoderBlockStruct blk_ptr, Av1BlockSize blockSize, Av1PredictionMode lumaMode, - Av1ChromaPredictionMode chromaMode, - bool isChromaFromLumaAllowed) + Av1ChromaPredictionMode chromaMode) { + bool isChromaFromLumaAllowed = blockSize.AllowsChromaFromLuma( + frameHeader.LosslessArray[macroBlockModeInfo.Block.SegmentId], + colorConfig.SubSamplingX, + colorConfig.SubSamplingY); + writer.WriteChromaMode(chromaMode, isChromaFromLumaAllowed, lumaMode); if (chromaMode == Av1ChromaPredictionMode.ChromaFromLuma) diff --git a/tests/ImageSharp.Tests/Formats/Heif/Av1/Av1CoefficientsEntropyTests.cs b/tests/ImageSharp.Tests/Formats/Heif/Av1/Av1CoefficientsEntropyTests.cs index a3cb99b6bf..67f5fb03e2 100644 --- a/tests/ImageSharp.Tests/Formats/Heif/Av1/Av1CoefficientsEntropyTests.cs +++ b/tests/ImageSharp.Tests/Formats/Heif/Av1/Av1CoefficientsEntropyTests.cs @@ -813,6 +813,74 @@ public class Av1CoefficientsEntropyTests Assert.True(expected.GetSpan().SequenceEqual(actual.GetSpan())); } + [Theory] + [InlineData((int)Av1BlockSize.Block4x4, false, false, true, true)] + [InlineData((int)Av1BlockSize.Block8x8, true, true, true, true)] + [InlineData((int)Av1BlockSize.Block8x8, false, false, true, false)] + [InlineData((int)Av1BlockSize.Block16x16, true, true, true, false)] + [InlineData((int)Av1BlockSize.Block32x32, true, true, false, true)] + [InlineData((int)Av1BlockSize.Block64x64, true, true, false, false)] + public void ChromaFromLumaAvailabilityUsesLosslessPlaneGeometry( + int blockSize, + bool subSamplingX, + bool subSamplingY, + bool isLossless, + bool expected) + => Assert.Equal( + expected, + ((Av1BlockSize)blockSize).AllowsChromaFromLuma(isLossless, subSamplingX, subSamplingY)); + + [Fact] + public void LosslessChromaModeUsesPlaneSizedChromaFromLumaAlphabet() + { + ObuFrameHeader frameHeader = new(); + frameHeader.LosslessArray[0] = true; + ObuColorConfig colorConfig = new() + { + SubSamplingX = true, + SubSamplingY = true + }; + + Av1MacroBlockModeInfo modeInfo = default; + modeInfo.Block.SegmentId = 0; + Av1EncoderBlockStruct block = default; + Av1BlockSize blockSize = Av1BlockSize.Block16x16; + ReadOnlySpan decisions = + [ + Av1ChromaPredictionMode.DC, + Av1ChromaPredictionMode.Smooth, + Av1ChromaPredictionMode.Paeth, + Av1ChromaPredictionMode.SmoothVertical, + Av1ChromaPredictionMode.DC, + Av1ChromaPredictionMode.SmoothHorizontal + ]; + + using Av1SymbolEncoder actualWriter = new(Configuration.Default, 16, BaseQIndex); + using Av1SymbolEncoder expectedWriter = new(Configuration.Default, 16, BaseQIndex); + foreach (Av1ChromaPredictionMode decision in decisions) + { + Av1TileWriter.EncodeIntraChromaMode( + actualWriter, + frameHeader, + colorConfig, + modeInfo, + ref block, + blockSize, + Av1PredictionMode.DC, + decision); + + expectedWriter.WriteChromaMode( + decision, + isChromaFromLumaAllowed: false, + Av1PredictionMode.DC); + } + + using IMemoryOwner actual = actualWriter.Exit(); + using IMemoryOwner expected = expectedWriter.Exit(); + + Assert.True(expected.GetSpan().SequenceEqual(actual.GetSpan())); + } + [Fact] public void RoundTripZeroEndOfBlock() {