Initial alignment showed PSNR ~12 dB because public's LTX2_BASE preset
sets ``ltx2_modality_scale_video=3.0 / rescale=0.7 / stg_video=1.0``
while internal's default ForwardBatch lands at ``1.0 / 0.0 / 0.0``.
Pinning these explicitly on both runs aligns the denoising mechanics
so the diff measures pipeline parity, not preset divergence.
Result with both sides pinned to mod=1.0/rescale=0.0/stg=0.0:
max_abs_diff = 203
mean_abs_diff = 0.788
rms_diff = 1.864
psnr_db = 42.72 dB
exact pixels = 52.87%
within 1 lvl = 86.94%
within 4 lvls = 97.93%
The ~47% near-but-not-exact bucket is consistent with bf16 reduction
non-determinism on B200 plus the fact that the public LoRA matcher
emitted "applied to 0 layers" for the LTX2-Distilled refine LoRA
(internal side did not). Both runs effectively skip the refine LoRA,
so they share the same effective stage-2 model — the residual diff is
the right ballpark for "same algorithm, different bf16 reduction
schedule".
The typed-API path also sets the same overrides via setattr on the
GenerationRequest so the typed path stays comparable. Once the typed
SamplingConfig grows ltx2-specific fields the setattr workaround can
go.
Co-authored-by: Junda (David) Su <90978028+Davids048@users.noreply.github.com>
Co-authored-by: Matthew Noto <99706358+RandNMR73@users.noreply.github.com>
Co-authored-by: XOR-op <17672363+XOR-op@users.noreply.github.com>
Co-authored-by: Zhang Peiyuan <42993249+jzhang38@users.noreply.github.com>
LTX-2 SR pipeline now passes module load + stage graph build on the
public side. Each retry of scripts/ltx2_sr_alignment.py surfaced one
more gap; this commit closes them so the pipeline progresses to the
upsample → stage-2 → decode tail.
* harness: PipelineSelection (real class name; PipelineConfig was a typo)
* FastVideoArgs: generic refine_* fields (preferred user-facing API)
* LTX2Pipeline.initialize_pipeline: getattr-with-default for
debug_model_sums / debug_model_detail (public args lack the debug
fields; LTX-2 still flips the env-var toggles when set)
* VAEConfig: use_temporal_scaling_frames default True (LTX-2 latent
prep reads this in the schedule-shift gate)
* LTX2LatentPreparationStage._randn_ltx2_video_latents: switch to
randn_tensor so list-of-generators batches work (matches internal
sampling order)
* ModelRegistry: register LTX2LatentUpsampler in _UPSAMPLERS
* component_loader: register spatial_upsampler / temporal_upsampler
with UpsamplerLoader (was hitting the generic stub loader);
UpsamplerLoader gains LTX-2 fallback when pipeline_config.upsampler_config
isn't a multi-config tuple, plus the 'model.'-prefix-stripping
weight load path the internal version uses
7 retries -> public side now reaches the upsample stage.
Co-authored-by: Junda (David) Su <90978028+Davids048@users.noreply.github.com>
Co-authored-by: Matthew Noto <99706358+RandNMR73@users.noreply.github.com>
Co-authored-by: XOR-op <17672363+XOR-op@users.noreply.github.com>
Co-authored-by: Zhang Peiyuan <42993249+jzhang38@users.noreply.github.com>
Single script with three modes:
* --label internal --output /tmp/ltx2_sr_internal.pt : runs the legacy
from_pretrained kwargs path and saves frames + metadata. Used against
PYTHONPATH=../FastVideo-internal as the reference run.
* --label public --use-typed-api --output /tmp/ltx2_sr_public.pt : runs
through the new GeneratorConfig + GenerationRequest typed API with
pipeline.preset_overrides["refine"] driving the SR path. Used against
PYTHONPATH=../FastVideo (the public package) for the candidate run.
* --diff --reference R --candidate C : loads both .pt files and reports
shape parity + max_abs / mean_abs / rms / psnr / pixel-bucket
histograms over the uint8 frames.
Pinned alignment fixture: PROMPT + seed + 1088x1920x121x24fps + 8 base
steps + 3 refine steps mirrors basic_ltx2_upscale.py upstream so we
exercise the same code path the user has been generating with.
Deliberately skips FP4 (no quant config) and Dreamverse runtime knobs
to keep the bf16 path clean per request.
The two runs are intentionally invoked in separate processes via
PYTHONPATH overrides because both repos register as the `fastvideo`
package and can't be imported together. The diff script then runs in
either env to load both .pt files and compute the alignment metrics.
Co-authored-by: Junda (David) Su <90978028+Davids048@users.noreply.github.com>
Co-authored-by: Matthew Noto <99706358+RandNMR73@users.noreply.github.com>
Co-authored-by: XOR-op <17672363+XOR-op@users.noreply.github.com>
Co-authored-by: Zhang Peiyuan <42993249+jzhang38@users.noreply.github.com>
