diff --git a/HEIF_IMPLEMENTATION_PLAN.md b/HEIF_IMPLEMENTATION_PLAN.md
index 07c926331..dfae2aea6 100644
--- a/HEIF_IMPLEMENTATION_PLAN.md
+++ b/HEIF_IMPLEMENTATION_PLAN.md
@@ -29,9 +29,11 @@ Checkboxes may be marked complete only when the implementation and the verificat
## Delivery dashboard
-Last reconciled with the source tree on 2026-08-29 against production checkpoint `c5637ea0187df35b385bf43e2fe85cd955f01099`. Committed checkpoints include the AV1 transform architecture, OBU framing, intra-block copy, 12-profile reconstruction matrix, layered-item properties, layered reference/header/CDF/motion-field state, inter-frame intra blocks, SIMD-first translational prediction, complete single-reference inter reconstruction, compound reference trees and modes, paired reference-MV derivation, reference-dependent bounded sequence decoding, allocation-free SIMD-first equal averaging, selected inter-intra prediction, selectable compound blending, OBMC, scaled-reference reconstruction, local warped prediction, and non-translational global prediction. The global-warp checkpoint reuses the committed affine filter for valid rotation/zoom and affine `GLOBALMV` models while preserving translational fallback for identity, translation, invalid shear, scaled references, integer-only frames, OBMC, and sub-8x8 plane predictions. Its genuine two-frame 256x256 bounded AVIF contains seven pinned-libaom-traced rotation/zoom `GLOBALMV` blocks and passes exact final pinned-libaom YUV444 planes, exact pinned-libavif RGBA presentation, normal and scalar `FeatureTestRunner` execution, constrained allocation, and balanced ownership tracking. A direct production-branch test drives both matrices of `GLOBAL_GLOBALMV` through compound averaging at 8, 10, and 12 bits. Both source targets build with zero warnings and errors; the `net10.0` test project builds with zero errors and pre-existing warnings; 84 focused `net10.0` cases pass without failures or skips; and the documentation and diff checks are complete. This dashboard is the authoritative delivery order. The detailed phase checklists below provide subsystem evidence; they do not override the current-stage marker or permit work to skip ahead.
+Last reconciled with the source tree on 2026-08-29 against production checkpoint `1c58d855f70b024170ced9eb0a7005f0f9c955ad`. Committed checkpoints include the AV1 transform architecture, OBU framing, intra-block copy, 12-profile reconstruction matrix, layered-item properties, layered reference/header/CDF/motion-field state, inter-frame intra blocks, SIMD-first translational prediction, complete single-reference inter reconstruction, compound reference trees and modes, paired reference-MV derivation, reference-dependent bounded sequence decoding, allocation-free SIMD-first equal averaging, selected inter-intra prediction, selectable compound blending, OBMC, scaled-reference reconstruction, local warped prediction, non-translational global prediction, and official motion-vector conformance. This dashboard is the authoritative delivery order. The detailed phase checklists below provide subsystem evidence; they do not override the current-stage marker or permit work to skip ahead.
-The working tree contains a complete, verified official motion-vector conformance checkpoint awaiting commit. The official IVF has SHA-1 `F064290D7FCD3B3DE19020E8AEC6C43C88D3A505`, matching the pinned libaom test-data manifest, and SHA-256 `222A9050059B254DAB17CFB802FF829C778E3F93AF18961A622C8268576C1395`; its pinned-libaom Y4M has SHA-256 `D97AC78C81782CF1507549368047769DC677DBE205706458D1EE9C807DE6EC78`. Both source targets build with zero warnings and errors, the `net10.0` test-project analyzer build completes with zero errors and 1,014 pre-existing repository warnings, Roslynk reports zero compiler errors, 3,985 focused `net10.0` cases pass without failures or skips, and `git diff --check` is clean.
+Commit `1c58d855f70b024170ced9eb0a7005f0f9c955ad` records the complete official motion-vector conformance checkpoint. The official IVF has SHA-1 `F064290D7FCD3B3DE19020E8AEC6C43C88D3A505`, matching the pinned libaom test-data manifest, and SHA-256 `222A9050059B254DAB17CFB802FF829C778E3F93AF18961A622C8268576C1395`; its pinned-libaom Y4M has SHA-256 `D97AC78C81782CF1507549368047769DC677DBE205706458D1EE9C807DE6EC78`. Both source targets build with zero warnings and errors, the `net10.0` test-project analyzer build completes with zero errors and 1,014 pre-existing repository warnings, Roslynk reports zero compiler errors, 3,985 focused `net10.0` cases pass without failures or skips, and `git diff --check` is clean.
+
+The working tree contains a complete, verified selected-spatial-layer presentation checkpoint awaiting commit. An essential `lsel` selecting the genuine 40x40 base layer of the committed 40x40-to-80x80 progressive AVIF returns that exact pinned-libaom native reconstruction, then scales its YUV444 planes to the 80x80 `ispe` extent before color conversion and matches pinned libavif's RGBA output exactly. Retained reconstructed planes remain at coded dimensions; presentation planes use group-safe allocator-owned rows and are returned exactly once under a 1,024-byte constrained allocator. Portable `Vector128` and scalar two-times filters match pinned libyuv edge, quarter-sample, and rounding results at 8 and 12 bits through `FeatureTestRunner`. Both source targets build with zero warnings and errors, the `net10.0` test-project analyzer build completes with zero errors and 1,014 pre-existing repository warnings, Roslynk reports zero compiler errors, 156 focused reconstruction and color cases pass without failures or skips, and `git diff --check` is clean.
Status meanings:
@@ -41,9 +43,9 @@ Status meanings:
- **Not started:** supporting primitives may exist, but the production format path is absent.
- **Current:** the only work item that should be advanced before taking the next queued item.
-Current development stage: **Stage 3 — complete AV1 still-image decoding.** The decoder retains reference/header/CDF/motion-field state, derives frame-level skip-mode references, consumes temporal segment prediction, decodes intra-coded blocks inside inter frames, and reconstructs translational single-reference, compound, inter-intra, OBMC, scaled-reference, local warped, and non-translational global prediction before residual traversal. Commit `c5637ea0187df35b385bf43e2fe85cd955f01099` records the global-warp checkpoint. The working tree additionally decodes the official four-frame motion-vector sequence exactly through all ordinary inter modes, all three motion modes, every regular/smooth/sharp dual-filter pair, sub-8x8 chroma prediction, and no-round compound intermediates. Neither AV1 nor HEVC production encoding is implemented.
+Current development stage: **Stage 3 — complete AV1 still-image decoding.** The decoder retains reference/header/CDF/motion-field state, derives frame-level skip-mode references, consumes temporal segment prediction, decodes intra-coded blocks inside inter frames, and reconstructs translational single-reference, compound, inter-intra, OBMC, scaled-reference, local warped, and non-translational global prediction before residual traversal. Commit `1c58d855f70b024170ced9eb0a7005f0f9c955ad` adds exact official four-frame coverage through all ordinary inter modes, all three motion modes, every regular/smooth/sharp dual-filter pair, sub-8x8 chroma prediction, and no-round compound intermediates. Neither AV1 nor HEVC production encoding is implemented.
-Immediate checkpoint: **commit the verified official motion-vector conformance slice before advancing.** Exact official native-plane comparison, normal/scalar dispatch, constrained allocation, sub-8x8 chroma, no-round compound arithmetic, Release builds, Roslyn/compiler checks, the focused suite, documentation review, and the diff gate all pass.
+Immediate checkpoint: **commit the verified selected-spatial-layer presentation slice before advancing.** The production container path returns the exact selected native layer, scales only its short-lived presentation planes, matches pinned libavif output, preserves final-layer and display-only film-grain behavior, passes constrained allocation, and has complete focused Release evidence.
| Order | Delivery stage | State | Delivered state | Gate that remains open |
| --- | --- | --- | --- | --- |
@@ -96,10 +98,10 @@ Immediate checkpoint: **commit the verified official motion-vector conformance s
- [x] Decode and independently verify scaled-reference prediction through exact Q14/Q10 arithmetic, allocation-free SIMD/scalar convolution, 8/10/12-bit production reconstruction, scaled OBMC, active inter deblocking, constrained allocation, and a genuine size-changing bounded AVIF.
- [x] Decode local warped motion through pinned integer projection and allocation-free SIMD-first affine filtering. A genuine two-frame bounded AVIF selects traced multi-sample warped blocks and passes exact final native-plane and presentation comparisons, constrained allocation, and normal/scalar dispatch. Commit `0b2db86809e26757460e719a6b59c0fe58bb0586` records the checkpoint.
- [x] Decode non-translational global motion through the committed affine filter. A genuine two-frame bounded AVIF selects seven traced rotation/zoom `GLOBALMV` blocks and passes exact final native-plane and presentation comparisons, constrained allocation, and normal/scalar dispatch. Direct 8/10/12-bit production reconstruction covers both matrices of compound `GLOBAL_GLOBALMV`. Commit `c5637ea0187df35b385bf43e2fe85cd955f01099` records the checkpoint.
- - [x] Decode the official `av1-1-b8-05-mv.ivf` sequence through every ordinary inter mode, all three motion modes, and every regular/smooth/sharp dual-filter pair; reconstruct sub-8x8 chroma and allocation-free no-round compound intermediates; and compare all four shown 352x288 YUV420 frames exactly with pinned-libaom output under normal/scalar dispatch and constrained tracked allocation. The official IVF SHA-1 matches the pinned libaom manifest. Both Release source targets build with zero warnings and errors; the `net10.0` test-project analyzer build completes with zero errors and 1,014 pre-existing repository warnings; Roslynk reports zero compiler errors; 3,983 focused decoder/predictor cases plus two complete official-sequence cases pass without failures or skips; and `git diff --check` is clean. The checkpoint is complete locally and awaiting commit.
- - [ ] **Queued until the official motion-vector checkpoint commit:** verify every remaining connected mode and filter with independently encoded bounded AV1 content and exact native-plane comparisons.
- - [ ] Return the explicitly selected spatial layer or the final displayed layer, keeping reference reconstruction separate from display-only film grain.
- - [ ] Verify color and auxiliary-alpha output exactly against both pinned libavif progressive fixtures under normal SIMD dispatch and all required `FeatureTestRunner` fallbacks.
+ - [x] Decode the official `av1-1-b8-05-mv.ivf` sequence through every ordinary inter mode, all three motion modes, and every regular/smooth/sharp dual-filter pair; reconstruct sub-8x8 chroma and allocation-free no-round compound intermediates; and compare all four shown 352x288 YUV420 frames exactly with pinned-libaom output under normal/scalar dispatch and constrained tracked allocation. The official IVF SHA-1 matches the pinned libaom manifest. Both Release source targets build with zero warnings and errors; the `net10.0` test-project analyzer build completes with zero errors and 1,014 pre-existing repository warnings; Roslynk reports zero compiler errors; 3,983 focused decoder/predictor cases plus two complete official-sequence cases pass without failures or skips; and `git diff --check` is clean. Commit `1c58d855f70b024170ced9eb0a7005f0f9c955ad` records the checkpoint.
+ - [x] Verify every connected inter mode and filter with exact independent content. The official pinned-libaom sequence supplies complete bit-mask coverage for all twelve ordinary inter modes, all three motion modes, and all nine regular/smooth/sharp dual-filter pairs. The committed average, selectable compound, inter-intra, OBMC, scaled-reference, local-warp, and global-warp AVIF fixtures separately require every connected reconstruction variant and pass exact native-plane comparison; the presentation-bearing fixtures also pass exact pinned-libavif output.
+ - [x] Return the explicitly selected spatial layer or the final displayed layer, keeping reference reconstruction separate from display-only film grain. The essential-`lsel` production fixture reconstructs the selected 40x40 YUV444 base exactly, scales native component planes to the 80x80 item extent with pinned-libyuv integer rounding, and matches pinned-libavif RGBA presentation under normal/scalar dispatch. The committed final-layer fixture and film-grain matrix remain exact. Constrained tracked allocation returns every short-lived presentation plane exactly once.
+ - [ ] **Queued until the selected-spatial-layer checkpoint commit:** verify color and auxiliary-alpha output exactly against both pinned libavif progressive fixtures under normal SIMD dispatch and all required `FeatureTestRunner` fallbacks.
- [ ] Correct the audited 12-bit inverse ADST4, Identity4, and Identity16 SIMD arithmetic by widening only the libaom-widened multiply/accumulate operations, with exact conformant-range vectors and `FeatureTestRunner` coverage.
- [ ] Continue inventorying and removing every remaining valid AV1 still-image unsupported branch, adding exact independent compression-tool fixtures to the profile-matrix regression gate.
- [ ] Complete the remaining HEVC still-image profile and Range Extensions matrix with exact independent native-plane and presentation evidence.
@@ -436,6 +438,7 @@ This assessment was reconciled with the source tree on 2026-08-29, including pro
- AV1 has focused bitstream, prediction, entropy, reconstruction, filter, film-grain, color, and transform coverage, plus real libavif inputs. A real two-layer libavif-derived OBU stream verifies the bounded frame lifecycle, retained-slot occupancy, resolved inter references, and `frame_size_with_refs` dimensions through a fake tile lifecycle. The corrected progressive color item then verifies its production single-reference inter branch against exact pinned-libaom native planes and pinned-libavif presentation. The pinned 19-frame YUV444 sequence separately reaches production equal-average compound reconstruction after every preceding reference sample and matches its final native and presented references exactly. A real palette stream truncated inside its tile entropy payload verifies libaom-equivalent overflow/trailing-bit rejection and decoder-session recovery. The committed equal-average checkpoint passes 119 direct focused cases plus three `FeatureTestRunner` cases, zero-warning `net10.0` and `net11.0` source builds, a zero-error test-project analyzer build with pre-existing repository warnings, allocator lifetime validation, and `git diff --check`. Four additional pinned sequences reach distance-weighted, both wedge signs, both difference-mask orientations, and smooth and wedge inter-intra reconstruction with exact final native and presented output. Commit `864b11ad9791d3254a38691246270c569001b5a1` records the selectable-compound checkpoint after both source targets, the test-project analyzer build, 25 direct focused cases, six `FeatureTestRunner` cases, constrained allocation, exactly-once tracked returns, and `git diff --check` passed. Commit `59a4fbad5ed3bc7c34331c4bdc65acc7acde3f04` adds exact traced OBMC sequence evidence, subsampled direct reconstruction, constrained allocation, both source builds, the analyzer build, 14 direct cases, the normal/scalar `FeatureTestRunner` comparison, and clean staged `git diff --check`. Commit `8f57c29b250b4291f034b31c1ea3de3fa3345467` adds a genuine size-changing layered AVIF, exact retained-base and final native planes, exact final presentation, active inter deblocking, constrained allocation, normal/scalar dispatch, direct 8/10/12-bit block reconstruction, and 87 passing focused cases. The local-warp checkpoint adds a genuine two-frame 256x256 bounded AVIF with many traced `WARPED_CAUSAL` blocks, exact pinned multi-sample projection, exact final native and presentation comparisons, constrained allocation, normal/scalar `FeatureTestRunner` dispatch, direct 8/10/12-bit predictor parity, zero-warning source builds, and 86 passing focused cases. Valid still-image syntax paths still contain explicit unsupported branches, so the independent AV1 decode matrix is not complete.
- Local-warp fixture provenance is pinned to libavif `062e582e8afda88e6baf988fdcf046a801efa0f5` and libaom `03087864cf4bea6abb0d28f95cf7843511413d8f`. A deterministic two-frame limited-range YUV444 grid sequence was encoded with `avifenc -j 1 -s 0 -q 60 -a color:enable-warped-motion=1 -a color:enable-global-motion=0 -a color:enable-obmc=0`. SHA-256 values are `990BAC4AD443005C217B0DA4FCCFA9ADFB3AA147AD06C85F9A655A4433E9E8A7` for the AVIF, `984B2815CEE0C05FDE26430F150A21B5C993141E25BA1ED4FDE09372DB64AC13` for the pinned-libaom frame-1 Y4M, and `4490D62FB6679378E92CACA48427359091AD2106BE49FC1A3848F78BE03BEEB1` for the pinned-libavif frame-1 PNG.
- Scaled-reference fixture provenance is pinned to libavif `062e582e8afda88e6baf988fdcf046a801efa0f5` and libaom `03087864cf4bea6abb0d28f95cf7843511413d8f`. The source is libavif `tests/data/webp_logo_animated.y4m`, encoded as two layered YUV444 inputs with `avifenc -j 1 -q 90 --layered --scaling-mode:u 1/2 --scaling-mode:u 1/1