feat(LTX25-A2VID-RECIPE): the audio-to-video recipe, and the phase field a boolean could not express (#1117)

.agents/issue-index.md

@@ -326,3 +326,5 @@ rather than merged. `scripts/check-agent-record.py` gates both.
 | [#1092](https://github.com/mudler/vllm.cpp/issues/1092) | `LTX25-GUIDED-VIDEO` | The LTX-2.5 **video** denoise loop runs one UNGUIDED forward per step: `Ltx2PhaseRecipe::video_guidance` is set by every recipe (`src/vllm/model_executor/models/ltx2_pipeline.cpp:1069 @ b5756ea8c`) and read by nothing, so a `pipeline_kind = one_stage` render ignores `cfg_scale = 3.0`, `stg_scale = 1.0`, `rescale_scale = 0.7` and `modality_scale = 3.0` and denoises along a different trajectory than `ti2vid_one_stage.py:221-226 @ fd4ded7f`, which builds a `FactoryGuidedDenoiser` from exactly those. `allow_guidance_override` (`ltx2_pipeline.h:534`) is dead the same way. Positive control for the grep: the same command for `audio_guidance` returns the T2A consumer at `ltx2_video.cpp:3527`. Blocks four more pipelines on one missing seam (`a2vid_two_stage.py:230`, `ti2vid_two_stages.py:248`, `ti2vid_two_stages_hq.py:271`, `keyframe_interpolation.py:232`). Spec [`ltx25-guided-video.md`](specs/ltx25-guided-video.md) | bug |
 | [#1111](https://github.com/mudler/vllm.cpp/issues/1111) | `LTX25-GUIDED-VIDEO` | `Ltx2T2aGuidedStep` (`src/vllm/model_executor/models/ltx2_t2a.cpp:203-214` @ `420f6b474`) builds the STG block mask and refuses when NO bit is set, and that one predicate catches two different things. One is a request that disagrees with the CHECKPOINT - `[28]` on a two-block DiT - which is a LOCAL condition, because upstream only ever runs 48-block checkpoints and this port runs reduced ones. The other is an EMPTY list, which is upstream's OWN documented spelling for "STG off" and is refused here. Measured at Lightricks/LTX-2 `fd4ded7f`: `ltx-pipelines/docs/multimodal-guidance.md:13` says "Set to `[]` to disable STG", in the same table and the same idiom as `stg_scale` -> 0.0 and `cfg_scale` -> 1.0; `MultiModalGuiderParams.stg_blocks` DEFAULTS to `[]` (`guiders.py:204`, `field(default_factory=list)`); `--audio-stg-blocks` is `nargs="*"` (`args.py:1039-1045`, `:1107-1113`) so the empty list has a CLI spelling, and `nargs="+"` was the one-character way to forbid it; `LTX_2_3_HQ_PARAMS` SHIPS `stg_blocks=[]` on both modalities (`constants.py:105,:113`); and a whole-tree search found NO validation of `stg_blocks` anywhere - no emptiness, length or range check, no assert, no raise - with the null results recorded. `blocks=None` means EVERY block and `blocks=[]` means NO block (`perturbations.py:26-33`), so the empty list is how a caller says the second thing, and both this tree's parsers go out of their way to keep PRESENT-and-empty distinct from ABSENT - then refuse the one configuration that distinction exists to express. Upstream does not skip the pass either: `do_perturbed_generation` reads `stg_scale` alone (`guiders.py:279-281`), so an empty list disables the STG SIGNAL and not the STG COST. FOUND while repairing the fresh review of [#1092](https://github.com/mudler/vllm.cpp/issues/1092), whose B3 finding is the same divergence on the VIDEO path; that half IS fixed in flow (`ltx2_video.cpp` `ApplyGuidanceOverrides`, `ltx2_denoisers.cpp` `check_reaches_a_block`). NOT fixed here because this half landed with [#1032](https://github.com/mudler/vllm.cpp/issues/1032) and moving it changes a landed row's gated behaviour and its case "a perturbed pass over NO block is refused", which is the normal row-spec-review path rather than an in-flow repair. Until then the two arms disagree about the same request. Listed under `## Owed` in [`ltx25-guided-video.md`](specs/ltx25-guided-video.md) | bug |
 | [#837](https://github.com/mudler/vllm.cpp/issues/837) | `ROCM-GEMMA4-GETBLAS-DUALSLOT` | ROCm: dual-slot GetBlas TLS + host lifetime so two HIP streams do not share one handle | bug |
+| [#1117](https://github.com/mudler/vllm.cpp/issues/1117) | `LTX25-A2VID-RECIPE` | `A2VidPipelineTwoStage` (`a2vid_two_stage.py:53` @ `fd4ded7f`) has no recipe row, so `pipeline_kind = a2vid_two_stage` gets the generic table refusal (`src/vllm/model_executor/models/ltx2_pipeline.cpp:1328-1332`) naming the pair rather than the missing machinery. [#922](https://github.com/mudler/vllm.cpp/issues/922) is CLOSED and closed the audio CONDITIONING, not the recipe: a supplied take rides `distilled_two_stage`, which [`ltx25-a2v-audio-input.md`](specs/ltx25-a2v-audio-input.md):438-446 already records as a different trajectory. Measured at `daeff67f2`: `git grep -n '"a2vid' -- src include tests docs examples` returns TWO hits, both upstream anchors inside `Fail`-message assertions (`tests/vllm/multimodal/test_ltx2_video.cpp:4363,:4427`), against a control of 4 for `"one_stage"` in `include/` alone. Four differences from the recipe it rides, each read at the pin: stage 1 is CFG/STG/modality-guided and caller-configured (`:230-240`, fed from `utils/args.py:947-1006`, `--a2v-guidance-scale` defaulting to `video_guider.modality_scale` = 3.0 at `utils/constants.py:54,:64`) where `distilled_two_stage` fixes `allow_guidance_override = false`; stage 1's schedule is scheduler-derived (`:225-227`) against our fixed `DistilledSigmas()`; stage 1 is plain Euler (`:229-258` passes no `stepper`, `utils/blocks.py:526-527`) against our `kEulerAncestral` on 2.5; and the AUDIO guider is the DEFAULT positive-only one (`:237-239`, `ltx-core components/guiders.py:200-210`) rather than the params table's cfg-7.0 row. Two non-schedule facts that must not be guessed: `--audio-path` is `required=True` (`:312-317`), and the distilled LoRA rides stage 2 ALONE (`:114` against `:107`) with `--distilled-lora` `required=True` (`utils/args.py:1140-1153`). Unblocked by `Ltx2GuidedDenoise` landing at `daeff67f2` (#1092/#1102), which [`ltx25-guided-video.md`](specs/ltx25-guided-video.md) `## Owed` names this arm against. Spec [`ltx25-a2vid-recipe.md`](specs/ltx25-a2vid-recipe.md) | enhancement |
+| [#1118](https://github.com/mudler/vllm.cpp/issues/1118) | `LTX25-A2VID-RECIPE` | LoRA adapters fuse ONCE, at load, into ONE weight set: `src/vllm/multimodal/ltx2_video.cpp:816-820` is the only `dit_options.loras.push_back` in the tree and it runs under `if (!lora_path.empty())`, so every phase of every recipe sees the same fused `im.dit.weights`. Three upstream pipelines build TWO `DiffusionStage`s from the same checkpoint with DIFFERENT adapter sets at `fd4ded7f`: `a2vid_two_stage.py:107` against `:114-119`, `ti2vid_two_stages.py:140` against `:151`, and `ti2vid_two_stages_hq.py:154,:165` at two separate strengths (`:92-101`). `distilled.py:131` builds ONE stage set, which is why `distilled_two_stage`, `dfr` and `retake` have never needed this and no gate has ever asked. Consequence for the arm landing with #1117: that row mirrors `--distilled-lora required=True` (`utils/args.py:1140-1153`) by refusing an `a2vid_two_stage` load with no `lora_path`, so the 3-step stage-2 schedule cannot run on a checkpoint with no distilled adapter — but it CANNOT mirror upstream leaving stage 1 WITHOUT that adapter, so stage 1's guided schedule runs against base + distilled LoRA where upstream runs it against the base alone. That divergence RENDERS, and the PIXELS it renders are not upstream's: it moves the trajectory, so the frames themselves differ, while the frame count, the shapes, the sample rate and the errors are all exactly what they were — nothing in the SHAPE of the result says anything is wrong, which is why it is filed rather than left in a comment. It is not undetectable, and saying so would be the more damaging error: the instrument that WOULD see it is a real-weights comparison against upstream's own render on the same checkpoint, take and seed, upstream's stage 1 on the base weights against ours on base + distilled. Two fix shapes, neither chosen: a second `Ltx2DitWeights` per adapter set (what upstream pays, two `from_checkpoint` calls at `a2vid_two_stage.py:103,:115`) or unfused runtime LoRA selectable per phase; the first doubles resident DiT weights and the second changes the GEMM path. Bounds #1093 and #921, which need the same seam. Listed under `## Owed` in [`ltx25-a2vid-recipe.md`](specs/ltx25-a2vid-recipe.md) | enhancement |