- [~] A non-owning encoder-frame view now separates visible conversion regions from coded regions and performs complete left, top, right, bottom, and corner extension across each bordered plane. Current libaom uses 8-sample-aligned coded dimensions, a 32-sample-aligned luma stride with chroma stride derived from it, and a 64-pixel luma border for non-resized all-intra encoding. One operation-ready frame owner now rents the aligned Y, U, and V storage contiguously, exposes non-owning `Buffer2D` plane views, and returns the rent exactly once. A 4K 4:2:0 frame occupies about 13.0 MiB at 8-bit or 26.0 MiB at 10/12-bit; source and reconstruction therefore remain distinct frame owners rather than adding a full-frame copy. The corrected tests use this real ownership path and verify the exact 54 KiB 64x64 4:2:0 rent. The frame-encoder operation now instantiates matching source and reconstruction owners with ordinary `using` lifetimes and converts packed pixels directly into the source owner before extension.
- [~] Temporal delimiter, sequence header, frame header, combined-frame tile-group writing, and an internal reduced-still-picture frame operation now exist locally. The remaining required metadata, padding, multi-tile, option, and public encoder paths are not complete.
- [~] Implement superblock and partition analysis for every permitted block size and partition. The current baseline deliberately splits every in-frame node to 8x8 blocks and records decisions in current-libaom writer preorder; block-size selection and non-split partition analysis remain.
- [] Implement intra mode search, chroma mode search, palette, filter intra, chroma-from-luma, and intra-block copy decisions.
- [~] Implement intra mode search, chroma mode search, palette, filter intra, chroma-from-luma, and intra-block copy decisions. Live luma search now covers DC and the complete zero-angle H, V, Smooth, Paeth, Smooth-V, and Smooth-H family; diagonal modes, angle deltas, and the remaining decision families remain.
- [ ] Implement inter mode search for bounded sequences, including reference selection and the decoder-supported inter tools.
- [~] Current-libaom `av1_quantize_fp_no_qmatrix` arithmetic is implemented as a closed generic forward-quantizer family with Vector512, Vector256, Vector128, and scalar paths, raster-order output, coded 64-point coefficient limits, and scan-order EOB selection. Transform search, coefficient optimization, and lossless behavior remain.
- [] Implement real rate-distortion selection and make quality and effort change work, size, and output quality.
- [~] Encoder rate accounting converts the entropy writer's live inverse cumulative distributions into current-libaom fixed-point symbol costs without allocating or duplicating probability state. Read-only luma-mode, directional-delta, filter-intra, chroma-mode, block-skip, transform-size, transform-block-skip, and complete transform-coefficient queries share the exact distributions mutated by the subsequent entropy write. Complete coefficient costing follows current libaom's optimized shape: it returns immediately for an empty transform, uses the EOB-specific base-range context, fuses magnitude, sign, base-range, and Golomb accounting into one reverse traversal, and combines repeated full base-range chunks instead of replaying each emitted symbol. Tile-lifetime level and context scratch is reused, the one-coefficient path neither clears nor initializes the forward-neighbor level map, and steady-state queries allocate nothing. Transform-size writing and costing share one subdivision-depth calculation, while shared closed symbol operations keep the writer and cost mappings for transform skip, transform type, and EOB syntax identical without forcing the estimator through the writer's slower two-pass coefficient traversal. The current-libaom fixed-point RD combiner preserves 64-bit distortion and rounds the weighted 1/512-bit rate at the required boundary. Its key-frame multiplier now follows libaom's squared DC-quantizer formula and exact 10/12-bit normalization. The first live final-block selection slice evaluates DC and zero-angle vertical luma prediction with complete transform, quantization, reconstruction, coefficient rate, and normalized pixel-domain distortion. The tile writer invokes this stack-only selector after mapping the current neighbors and immediately before writing each block, so later decisions see reconstructed samples, coefficient contexts, and CDF updates from every preceding block. Block skip is read only after the callback has combined every coded plane. Candidate scratch is limited to one 8x8 reconstruction and one 8x8 coefficient span on the stack; only the winning candidate is copied into retained frame storage. Focused rate, SIMD distortion, high-bit-depth normalization, live-CDF, skip-ordering, and production vertical-selection coverage passes 1,933 of 1,933 direct net11 Release VSTest cases. All 8,900 HEIF/AV1 namespace cases pass, and current-main `aomdec` accepts all 29 emitted 8/10/12-bit 4:0:0, 4:2:0, 4:2:2, and 4:4:4 constant or gradient payloads. Remaining mode decision work includes the other intra modes and angle deltas, transform-size/type search, chroma-mode search, partition search, full block-skip RD comparison, and effort-dependent pruning.
- [~] Implement real rate-distortion selection and make quality and effort change work, size, and output quality. The live zero-angle luma slice performs complete rate-distortion selection; quality mapping, effort-dependent pruning, and the remaining searches are not implemented.
- [~] Encoder rate accounting converts the entropy writer's live inverse cumulative distributions into current-libaom fixed-point symbol costs without allocating or duplicating probability state. Read-only luma-mode, directional-delta, filter-intra, chroma-mode, block-skip, transform-size, transform-block-skip, and complete transform-coefficient queries share the exact distributions mutated by the subsequent entropy write. Complete coefficient costing follows current libaom's optimized shape: it returns immediately for an empty transform, uses the EOB-specific base-range context, fuses magnitude, sign, base-range, and Golomb accounting into one reverse traversal, and combines repeated full base-range chunks instead of replaying each emitted symbol. Tile-lifetime level and context scratch is reused, the one-coefficient path neither clears nor initializes the forward-neighbor level map, and steady-state queries allocate nothing. Transform-size writing and costing share one subdivision-depth calculation, while shared closed symbol operations keep the writer and cost mappings for transform skip, transform type, and EOB syntax identical without forcing the estimator through the writer's slower two-pass coefficient traversal. The current-libaom fixed-point RD combiner preserves 64-bit distortion and rounds the weighted 1/512-bit rate at the required boundary. Its key-frame multiplier follows libaom's squared DC-quantizer formula and exact 10/12-bit normalization. Live final-block selection now evaluates DC, H, V, Smooth, Paeth, Smooth-V, and Smooth-H in current libaom's base-mode search order with complete transform, quantization, reconstruction, coefficient rate, and normalized pixel-domain distortion. Missing top or left edges and the Paeth corner are synthesized from the closest coded edge or the bit-depth midpoint offsets using the same rules as current libaom, so tile-edge modes are evaluated instead of incorrectly removed. The tile writer invokes this stack-only selector after mapping current neighbors and immediately before writing each block, so later decisions see reconstructed samples, coefficient contexts, and CDF updates from every preceding block. Block skip is read only after the callback has combined every coded plane. Candidate scratch remains one 8x8 reconstruction and one 8x8 coefficient span on the stack; only a newly winning candidate is copied into retained frame storage. Six independent production fixtures force each added predictor from already reconstructed top, left, and corner regions. The exact net11 Release rebuild remains at 1,005 warnings and zero errors, 36 focused predictor, block, mode-decision, and frame-operation cases pass, all 8,905 HEIF/AV1 namespace cases pass, and current-main `aomdec` accepts all 29 emitted 8/10/12-bit 4:0:0, 4:2:0, 4:2:2, and 4:4:4 constant or gradient payloads. Remaining mode decision work includes the six diagonal base modes and their angle deltas, transform-size/type search, chroma-mode search, partition search, full block-skip RD comparison, and effort-dependent pruning.
- [~] The tile writer now publishes one packed coefficient context per covered 4x4 edge unit and derives luma/chroma skip plus DC-sign contexts from the complete transform edges using current-libaom units. Partition, transform, and coefficient neighbor state retains only the above and left context regions used by current libaom; the unused third top-left region, its granularity state, and its unused sentinel are removed. One picture owner now packs segmentation plus every tile's partition, luma, chroma, and transform edges into one clean byte allocation with typed non-owning views; together with the separately typed packed mode-information owner, the complete picture state uses two allocator rents rather than seven. Exact aligned lengths, clean initialization, and balanced exactly-once returns are covered in Release. Multi-tile payload ownership and verified CDF update behavior remain.
- [~] 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. The visible dimensions are aligned to eight luma samples, the grid stride and allocated row count are aligned to 32 mode-information units, and optional 8x8 allocation granularity reduces the value store in both dimensions exactly as current libaom does. One clean ImageSharp byte owner contains both independently typed regions, reducing libaom's two allocation lifetimes to one without a copy. At 4K, the 4x4 layout occupies about 6.0 MiB in total; the 8x8 layout occupies about 3.0 MiB. Exact geometry, clean allocation, typed lengths, aligned mapping, untouched row padding, and exactly-once return pass 4 of 4 direct net11 VSTest cases in Release. Every coded 4x4 cell covered by square, rectangular, or clipped edge blocks maps to its owning allocation entry before context-dependent symbols are written. 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. Construction and the explicit per-superblock reset initialize every syntax field, including the nonzero sentinel that disables filter-intra prediction; pooled palette, quantizer, prediction, and partition bytes cannot leak into the next decision pass. Exact allocation, size, initialization, reset, return, repeated-run, writer, entropy, and OBU coverage pass 1,957 of 1,957 direct net11 VSTest cases in Release; complete mode decision still remains.
@ -841,9 +841,9 @@ Encoder verification contract:
- [~] The unused coefficient-shape transform facade and its unimplemented N2, N4, and DC-only branches are removed. Finalized block encoding now follows the complete-transform path that current libaom uses before fast quantization; later rate-distortion search may add proven coefficient optimization without exposing inactive runtime throws.
- [~] Forward-quantizer FeatureTestRunner and zero-allocation tests compare every hardware tier with an independent scan-order scalar oracle shaped from current-main libaom. Both passed direct net11 VSTest in Release.
- [~] The combined-frame writer now completes the byte-counted uncompressed frame header before starting the optional multi-tile tile-group flag, matching current libaom's separate frame-header and tile-group writers. A non-uniform two-tile round trip verifies the explicit boundaries, both tile payloads, and complete stream consumption through direct net11 VSTest in Release.
- [~] The first internal frame-to-OBU operation encodes 8-, 10-, and 12-bit monochrome reduced still pictures through the production tile writer and production decoder. Coefficient context initialization now stores `min(abs(level), 127)`, matching current libaom; the previous signed clamp converted every negative transform coefficient to zero and selected invalid nonzero-map distributions. Signed dense and sparse entropy round trips, direct level-buffer saturation coverage, and eight constant/gradient frame cases pass 52 of 52 direct net11 VSTest cases in Release. Current-main `aomdec` accepts all eight emitted payloads. Their decoded-frame MD5 values are `d09ea148582b9c93fa78e59426193bbc` (16x16 8-bit constant), `14e7d5ee5f70ad21972b88700338f32b` (16x16 8-bit gradient), `f949f7422913e83dff07ee5e0a5087d3` (8x8 8-bit constant), `ae7233a94558978934469dcc4da764dd` (8x8 8-bit gradient), `09223b227f3abc3134d0a3ea15f70c0a` (8x8 10-bit constant), `539aab0e6e14bcaec271febfa8e25444` (8x8 10-bit gradient), `73117a8fc102e5d028f82444fc4d15ab` (8x8 12-bit constant), and `0a7c7e058d8f56e6f3685c8eb8c3ece0` (8x8 12-bit gradient). This is an independently decodable baseline, not completion evidence for chroma, alpha, options, containers, or the public encoder.
- [~] The first internal frame-to-OBU operation encodes 8-, 10-, and 12-bit monochrome reduced still pictures through the production tile writer and production decoder. Coefficient context initialization now stores `min(abs(level), 127)`, matching current libaom; the previous signed clamp converted every negative transform coefficient to zero and selected invalid nonzero-map distributions. Signed dense and sparse entropy round trips, direct level-buffer saturation coverage, and eight constant/gradient frame cases pass 52 of 52 direct net11 VSTest cases in Release. Current-main `aomdec` accepts all eight emitted payloads. Their decoded-frame MD5 values are `d09ea148582b9c93fa78e59426193bbc` (16x16 8-bit constant), `025f6cf3f67b3f785e60b4d7d473eaab` (16x16 8-bit gradient), `f949f7422913e83dff07ee5e0a5087d3` (8x8 8-bit constant), `ae7233a94558978934469dcc4da764dd` (8x8 8-bit gradient), `09223b227f3abc3134d0a3ea15f70c0a` (8x8 10-bit constant), `539aab0e6e14bcaec271febfa8e25444` (8x8 10-bit gradient), `73117a8fc102e5d028f82444fc4d15ab` (8x8 12-bit constant), and `3cbecfd4eb5b8aeb7520e57927d6b6ba` (8x8 12-bit gradient). This is an independently decodable baseline, not completion evidence for chroma, alpha, options, containers, or the public encoder.
- [x] The exact net11 Release rebuild completed at the established 1,005-warning repository baseline with zero errors. The complete HEIF/AV1 namespace passes 8,838 of 8,838 direct VSTest cases with zero failures or skips. Roslynk reports zero compiler errors and no diagnostics in the five changed C# files; `git diff --check` passes and `.gitattributes` is unchanged.
- [~] The same internal frame operation now produces 4:2:0, 4:2:2, and 4:4:4 payloads at 8, 10, and 12 bits. Twenty-one color cases cover constant and spatially varying input at aligned dimensions plus odd 13x11 visible dimensions for every chroma geometry. The production decoder consumes every payload, the decoded output retains non-neutral chroma, and current-main `aomdec` accepts all 29 monochrome and color outputs. The odd-dimension decoded-frame MD5 values are `d025030a44750e703bcca9a6d3e131e8` (4:2:0), `75936a76104ec678c7a1f10b4c560172` (4:2:2), and `044026b1518aa94f3c2db82c7247c0d6` (4:4:4). This proves legal current-libaom payload syntax across native plane geometries; it does not yet prove target quality or native-plane equality with an independently encoded reference.
- [~] The same internal frame operation now produces 4:2:0, 4:2:2, and 4:4:4 payloads at 8, 10, and 12 bits. Twenty-one color cases cover constant and spatially varying input at aligned dimensions plus odd 13x11 visible dimensions for every chroma geometry. The production decoder consumes every payload, the decoded output retains non-neutral chroma, and current-main `aomdec` accepts all 29 monochrome and color outputs. The odd-dimension decoded-frame MD5 values are `ea9a80d0588607172311929c068339e1` (4:2:0), `24156ad83a1da448dd41b584a526d27b` (4:2:2), and `a17143c95acc91bdb54714fa79bdb7d2` (4:4:4). This proves legal current-libaom payload syntax across native plane geometries; it does not yet prove target quality or native-plane equality with an independently encoded reference.
- [x] The expanded checkpoint exposed a pre-existing transform-block test that asserted uninitialized pooled padding was zero. The test now initializes the complete physical luma plane with a sentinel and proves the block operation leaves both adjacent padding samples unchanged. The exact net11 Release rebuild remains at 1,005 baseline warnings and zero errors, the focused allocator-order set passes 30 of 30 cases, and the complete HEIF/AV1 namespace passes 8,859 of 8,859 direct VSTest cases with zero failures or skips.
- [x] Combined-frame OBU output now counts the byte-aligned frame and tile-group headers, non-final tile-size fields, and owned tile payloads before emitting the OBU size. It retains only the small allocator-owned header scratch and writes each entropy-coded tile span directly from its detached owner, removing the second file-sized allocator rent and complete-payload copy. A 64 KiB regression proves exactly one sub-payload-sized byte rent with a balanced return and verifies the exact streamed tile tail; the existing two-tile round trip proves size-prefix and ordering parity. The focused writer and production-frame set passes 32 of 32 direct net11 VSTest cases, current-main `aomdec` accepts all 29 generated native-format payloads, and the complete HEIF/AV1 namespace passes 8,860 of 8,860 cases with zero failures or skips.
- [x] Finalized fixed-block decisions now set the block-level transform-skip flag only when every retained luma and coded chroma transform has zero EOB, matching current libaom's conjunction of per-plane skip state. The previous always-false flag produced legal but redundant non-skip and zero-coefficient syntax. Monochrome and 4:2:0 regressions prove both branches from actual coefficient state; the focused decision and production-frame set passes 32 of 32 direct net11 VSTest cases. Current-main `aomdec` accepts all 29 regenerated payloads, the recorded decoded-frame MD5s are unchanged, and affected 16x16 constant 8-bit and 10-bit payloads are one byte smaller. The complete HEIF/AV1 namespace passes 8,862 of 8,862 cases with zero failures or skips.