[tests] refactor ltx2 dfr pipeline tests - #14655
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Ports DFRPipeline from the Lightricks reference. Stage 1 generates video plus single-pixel-frame keyframe slots at a fraction of the requested resolution on a VAE-aligned segment grid; both are spatially latent-upsampled and stage 2 re-denoises at twice that resolution with the slots re-attached and an optional spatial detailing IC-LoRA active for that stage only. Optional temporal x2/x4 refine rounds tile the canvas at shared keyframes and densify with ancestral Euler. With spatial_upscalings=2 a full-resolution detailing epilogue follows the rounds. The transformer already stored keyframes_abs_pos_embedding for load/save; this wires it into the forward through a new video_keyframes_mask argument, which only a keyframes-aware pipeline passes, so other pipelines are unaffected. The epilogue denoises the whole canvas in one loop and tiles the transformer call inside it, so every Euler step steps a canvas whose tiles have already agreed on their overlaps. Spatial tiles blend under a trapezoidal mask, since neither side of a height or width border holds a known answer. Temporal tiles are cut on the keyframe seams the last refine round stitched on: both windows reproduce a shared keyframe there, so the later one drops its run-up under a rectangular mask rather than averaging it. Conditionings are attached once on the whole canvas and filtered per tile at the token level, and a keyframe two windows share is one token they both read. The epilogue is handed its keyframes rather than asked to generate them. Each carry plane is decoded on its own -- the VAE is causal, so a stacked decode would bleed neighbours -- then Lanczos-stretched x2 in RGB and encoded again at the output resolution, and pinned fully clean. Only the video latent is spatially upsampled. Conditioning fps is snapped to 60 above 30 rather than merely capped there, at every stage. RoPE time is pixel_frame / fps, and the transformer is trained around 24/25/30 and 60; a temporal round taking 24 fps to 48 lands between those, and it shows as stutter at the latent borders. Playback fps is unchanged, so 24 fps with one round still ships 48 fps. A condition's index is read on the canvas num_frames asks for, and the moment it names is carried onto each refine round's longer canvas by scaling its pixel position by 2**round. The scaled position does not generally land on a latent boundary, so it travels as a pixel index rather than through the public latent index; a keyframe conditioning is appended as extra tokens instead of being spliced into the base grid, so it does not need to. height and width must be divisible by 2**spatial_upscalings times the VAE's spatial compression ratio, which makes 4K 3840x2176 rather than 3840x2160. That rule is checked ahead of the looser one every LTX-2 pipeline applies, so the error names the divisor a DFR caller actually has to satisfy. Four details are easy to get wrong, and each is covered by a test after showing up as a visible seam at a tile handover: - The ancestral step injects noise into every token, so the conditioning blend has to be re-applied afterwards. Skipping it lets the strength-0.95 anchor keyframes erode over the schedule, and those anchors are the only thing pinning adjacent tiles onto the same content. - Velocity is converted to x0 with each token's own noise level, not the scalar schedule sigma: a token held at strength s sits at (1 - s) * sigma. - Each tile draws its ancestral noise from a generator seeded seed + 1000 * round + tile, kept separate from the main generator so the draws do not consume state the next tile's initial noising reads. - Two tiles invent the slot that falls in the later one's dropped lead-in. The stitch keeps the earlier tile's frames there, so the earlier tile's copy is the one the canvas holds, and the one the next round must anchor on.
Addresses the review on #14567: use the same compose pattern as the other LTX two-stage pipelines, get ancestral Euler from an existing scheduler, and put the temporal rounds in their own pipeline so the schedule is not switched mid-call. `LTX2DFRPipeline.__call__` is now one denoise pass at `height` x `width`. Callers compose stage 1, `LTX2LatentUpsamplePipeline`, stage 2 and each temporal round, and a documented recipe is the copy-paste 1080p path. The recipe knobs (`spatial_upscalings`, `temporal_upscalings`, `detailing_lora_adapter_name`) and the required upsampler components are gone; `height`/`width` are this pass, not the final output. `ancestral_euler_step` is replaced by `LTXEulerAncestralRFScheduler.step` plus a re-application of the conditioning blend, which ancestral noise would otherwise erode on the strength-0.95 seam anchors. The new `LTX2DFRTemporalRefinePipeline` owns that scheduler and one round; stage 1, stage 2 and the epilogue stay on `FlowMatchEulerDiscreteScheduler`. It refuses any other scheduler rather than silently taking a deterministic step and returning a softer canvas. Pack/unpack, `prepare_latents`, `denoise` and `encode_conditions` move to `LTX2DFRCoreMixin` so neither pipeline subclasses the other. Public latents are raw on both sides of every boundary, `output_type="latent"` returns the untrimmed canvas so a slot on the pad is not dropped, and `trim_canvas` does the trim before decode. `LTX2DFRPipelineOutput` carries `keyframes` and `keyframe_positions`, which cannot be re-derived after a round. Verified against the pre-split implementation: bit-exact on dummy components in fp32 and bf16, with and without the IC-LoRA reference, over one and two rounds; and within one bf16 ulp on the real checkpoint, where the only difference is that the split normalizes upsampled latents in fp32 rather than bf16. Also in this pass: - `__call__` takes `video_tiles` (the `epilogue_tiles` layout) instead of a resolved token plan. Resolving one needs the RoPE coordinates that only exist once `prepare_latents` has run, so a caller could not build the plan at all. - `rebuild_epilogue_keyframes` is public and takes and returns raw latents. The composed epilogue needs it, so it was public API in practice while named private, and its normalized return forced callers into `_denormalize_latents`. - Drop prompt enhancement and `num_videos_per_prompt` from the temporal pipeline. Enhancement belongs to stage 1 -- re-running it would denoise the canvas under a different prompt than the one that generated it -- and the batch is set by the incoming latent canvas, so `num_videos_per_prompt > 1` only ever raised. - Fix the docs recipe: `requested_frames` counted latent frames where `trim_canvas` wants pixel frames, truncating a 241-frame render to 25; the three pipelines share components, so place them together instead of offloading one and leaving `temporal_latent_upsampler` off the device; and the detailing IC-LoRA is applied at 0.5, the strength the reference hardcodes. - Pass `crf=0` on the conditions in the refine-round test. The default CRF sends the image through H.264 re-compression, which needs PyAV, so the test failed on any environment without it while testing nothing about re-compression.
Each DFR pipeline now owns pack/unpack, prepare_latents, and denoise so the classes stay self-contained. Shared helpers copy from LTX2Pipeline / LTX2ConditionPipeline, and DFR-specific methods copy from LTX2DFRPipeline. dfr_core.py keeps only the constants and canvas helpers.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
… convention; update docs and pipeline output accordingly Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
yiyixuxu
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Aug 31, 2026
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| # Copyright 2026 The HuggingFace Team. | |||
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ohh i thought we were removing this test?
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Commit shenanigans. Thanks for catching it. Removed.
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/diffusers-bot pytest tests/pipelines/ltx2 |
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As discussed on the PR.