* Add ACE-Step pipeline for text-to-music generation
Rebased on origin/main from the original pr-13095 branch (3 commits squashed).
- AceStepDiTModel: Diffusion Transformer with RoPE, GQA, sliding window,
AdaLN timestep conditioning, and cross-attention.
- AceStepConditionEncoder: fuses text / lyric / timbre into a single
cross-attention sequence.
- AceStepPipeline: text2music / cover / repaint / extract / lego / complete.
- Conversion script for the original checkpoint layout.
- Docs + tests.
* Fix ACE-Step pipeline audio quality and auto-detect turbo/base/sft variants
The PR's original inference produced low-quality audio on turbo because the
pipeline (a) mangled the SFT prompt format, (b) applied classifier-free guidance
with the wrong unconditional embedding (empty-string encoded vs. the learned
`null_condition_emb`), and (c) hardcoded turbo defaults even when loading a
base/SFT checkpoint.
Changes:
* Converter preserves `null_condition_emb` (stored under the condition encoder)
and propagates `is_turbo`/`model_version` into the transformer config so the
pipeline can route per-variant defaults.
* `AceStepConditionEncoder` registers `null_condition_emb` as a learned
parameter matching the original module.
* Pipeline auto-detects variant via `is_turbo`/`model_version` and picks
defaults that match `acestep/inference.py`:
* turbo: steps=8, shift=3.0, guidance_scale=1.0 (no CFG)
* base/SFT: steps=27, shift=1.0, guidance_scale=7.0
* Base/SFT timestep schedule uses the linear+shift transform from
`acestep/models/base/modeling_acestep_v15_base.py`; turbo still uses the
hardcoded 8-step `SHIFT_TIMESTEPS` table.
* CFG reuses the learned `null_condition_emb` and batches the
conditional+unconditional forwards into a single transformer call.
* `SFT_GEN_PROMPT` matches the newline layout in `acestep/constants.py` so the
text encoder sees the same prompt distribution it was trained on.
DiT parity vs. the original ACE-Step 1.5 turbo DiT is bit-identical
(max_abs=0.0 in fp32 eager/SDPA across 4 seed/shape cases) — see
scripts/dit_parity_test.py.
* Add ACE-Step parity test scripts
Two developer-facing parity harnesses live under scripts/:
* dit_parity_test.py — loads the same converted turbo weights into the
original AceStepDiTModel and the diffusers AceStepDiTModel, drives
identical (hidden_states, timestep, timestep_r, encoder_hidden_states,
context_latents) inputs, and asserts max-abs-diff ≤ 1e-5 in fp32
eager/SDPA. Currently passes bit-identical (max_abs=0) across four
shape/seed cases including batched + odd-length paths.
* audio_parity_jieyue.py — full end-to-end audio parity. Given the same
JSON example, runs both the original ACE-Step 1.5 pipeline and the
diffusers AceStepPipeline at matched seed/precision (bf16 + FA2 by
default) and saves side-by-side .wav files for listening verification.
Supports text2music / cover / repaint × turbo / base / sft via a
--matrix mode that writes 18 wavs named
{variant}_{task}_{official,diffusers}.wav.
* Route SFT parity to acestep-v15-sft checkpoint
On jieyue the release tree has a dedicated SFT checkpoint at
checkpoints/acestep-v15-sft with its own modeling_acestep_v15_base.py
shipped under acestep/models/sft/. Point the SFT row of the parity matrix
at that checkpoint / module so we're testing the actual SFT weights, not
the plain base ones.
* audio_parity_jieyue: fix doubled 'acestep-' in cache path; --converted-root flag
Previously the converted-pipeline cache dir was
`/tmp/acestep-<variant>-diffusers` but <variant> already starts with
"acestep-", giving `/tmp/acestep-acestep-v15-turbo-diffusers`. Drop the
prefix.
On jieyue the overlay rootfs (including /tmp) only has a few GB free; a
full turbo conversion needs ~5 GB per variant. Add --converted-root (env
ACESTEP_CONVERTED_ROOT) so the cache can live on vepfs.
* audio_parity_jieyue: two-phase matrix bootstraps cover/repaint from text2music
The ACE-Step release bundle on jieyue doesn't ship sample .wav/.mp3
files, so matrix mode had no default --src-audio and would skip
cover/repaint entirely. Run text2music first for every variant, then
reuse the TURBO official text2music output as the shared source for the
cover/repaint rows. Users can still override with --src-audio.
* audio_parity_jieyue: seed the diffusers generator on the pipeline device
The ORIGINAL ACE-Step pipeline seeds on the execution device
(`torch.Generator(device=device).manual_seed(seed)`), i.e. the CUDA RNG
stream when running on GPU. Previously the parity harness seeded the
diffusers side with a CPU generator, so even though the seed integer
matched, the two sides drew different noise from the outset and the
final outputs were essentially uncorrelated. Use the execution-device
generator on both sides for a fair comparison.
* Fix ACE-Step pipeline: switch to APG guidance + peak normalization
Two issues found after the first jieyue audio parity run:
1. The original base/SFT pipeline uses APG (Adaptive Projected Guidance,
acestep/models/common/apg_guidance.py) with a stateful momentum
buffer and norm/projection steps — NOT vanilla CFG. Using vanilla CFG
produced uncorrelated outputs vs. the reference (pearson ~0.0 on
20 s samples); this PR ports `_apg_forward` + `_APGMomentumBuffer`
and plugs them into the denoising loop when `guidance_scale > 1`.
Momentum is instantiated once per pipeline call (persists across
denoising steps) to match the reference semantics.
2. The post-VAE "anti-clipping normalization" in this pipeline was
`audio /= std * 5` with a `std<1 -> std=1` guard. The original
post-processing in
acestep/core/generation/handler/generate_music_decode.py is simple
peak normalization: `if audio.abs().max() > 1: audio /= peak`. The
std-based proxy both (a) let clips with peak < 1 leak through
unchanged (over-quiet) and (b) failed to bring clipping peaks to
exactly 1 in a bunch of base/SFT cases (observed max=1.000, std=0.200
repeatedly in the first parity run). Switch to peak normalization on
both sides.
Tested via scripts/audio_parity_jieyue.py on A800; re-run pending to
confirm the base/SFT correlation improvements.
* Fix ACE-Step chunk mask values to match the original pipeline
The DiT receives `context_latents = concat(src_latents, chunk_mask)` on the
channel dim, and was trained with chunk_mask values drawn from the three
sentinels documented in acestep/inference.py:
2.0 -> model-decided (default for text2music / cover / full-generation)
1.0 -> keep this latent frame from src_latents (repaint preserved region)
0.0 -> explicitly repaint this frame (only inside the repaint window)
Previously _build_chunk_mask returned all-1.0 for text2music (and cover /
lego), and an inverted 0/1 mask for repaint (1 inside the window, 0 outside).
Either case puts context_latents out of distribution. Switch text2music /
cover to the 2.0 sentinel and flip the repaint mask so it's 1.0 outside /
0.0 inside. Update the repaint src_latents zero-out to multiply by the new
mask (was `1 - chunk_mask`) so the zero region still lines up with the
repaint window.
* Add direct invoker for ACE-Step generate_music (ground truth)
Our earlier audio_parity_jieyue.py reconstructs the original pipeline by
calling AceStepConditionGenerationModel.generate_audio() directly, which
silently skips a lot of the real handler plumbing (conditioning masks,
silence-latent tiling, cover/repaint pre-processing, etc.). That made the
'official' wavs we saved sound wrong — flat, drone-like, not music.
This new script calls acestep.inference.generate_music end-to-end through
the real AceStepHandler, with LM + CoT explicitly disabled so we still have
a deterministic comparison. Use it to generate the ground-truth 'official'
wav for a given JSON example, then separately run the diffusers pipeline
with the same inputs and diff the two.
* run_official_generate_music: call initialize_service to bind a DiT variant
AceStepHandler() is a shell — you have to call handler.initialize_service(
project_root=..., config_path=..., device=..., use_flash_attention=..., ...)
before generate_music will work. Mirror what cli.py does at the equivalent
spot (around cli.py:1400).
* Fix silence-reference for ACE-Step timbre encoder
The root cause for the flat / drone-like outputs I was seeing (including
in my 'official' reconstruction): when no reference_audio is provided the
pipeline was feeding literal zeros to the timbre encoder. The real
handler feeds a slice of the learned `silence_latent` tensor.
The handler also transposes silence_latent on load (see
acestep/core/generation/handler/init_service_loader.py:214:
self.silence_latent = torch.load(...).transpose(1, 2)
) converting [1, 64, 15000] -> [1, 15000, 64] so that
`silence_latent[:, :750, :]` yields the expected [1, 750, 64] shape.
Changes:
* Converter: load silence_latent.pt, transpose to [1, T, C], bake into
the condition_encoder safetensors under key `silence_latent`.
(Also keeps the raw .pt file at the pipeline root for debugging.)
* AceStepConditionEncoder: register `silence_latent` as a persistent
buffer so from_pretrained loads it alongside the trained weights.
* Pipeline: when reference_audio is None, slice
`condition_encoder.silence_latent[:, :timbre_fix_frame, :]` and
broadcast across the batch instead of zeros. Emits a loud warning
(and falls back to zeros) if the buffer is all-zero — that means the
checkpoint was produced by an older converter and should be rebuilt.
* audio_parity_jieyue.py: the reference path now matches the handler's
silence-latent slicing.
Without this fix, every variant/task combo produced drone-like audio
even when my numeric DiT-forward parity claimed they were identical.
* Fix three more ACE-Step pipeline bugs I found by dumping real inputs
Instrumented the live generate_audio call in the real ACE-Step handler and
observed the exact tensors it sees — my diffusers pipeline was wrong in
three independent ways:
1. src_latents for text2music should be silence_latent tiled to
latent_length, NOT zeros. The handler fills no-target cases from
silence_latent_tiled (observed std=0.96). Zeros are OOD for the DiT
context_latents concat and produce drone-like outputs.
2. chunk_mask values cap at 1.0 (not 2.0). The handler starts with a
bool tensor (True inside the generate span, False outside); the
chunk_mask_modes=auto -> 2.0 override does NOT take effect because
the underlying tensor is bool, so setting entry = 2.0 casts to True.
After the later .to(dtype) float cast, the DiT sees 1.0/0.0 — exactly
what I observed in the captured tensor (unique values = [True]).
3. Default shift is 1.0 for ALL variants, including turbo. I was
defaulting turbo to shift=3.0 which picks a different SHIFT_TIMESTEPS
table (the 8-step schedule is keyed by shift, not variant).
Also:
* Added _silence_latent_tiled() helper that slices / tiles the learned
silence_latent (now loaded as a buffer on the condition encoder) to
the requested latent length.
* Repaint path now substitutes silence_latent (not raw zeros) inside
the repaint window — matches conditioning_masks.py.
* audio_parity_jieyue.py mirrors the same src/chunk/shift choices on
its 'original' leg for apples-to-apples parity once the buggy
reconstruction is removed from the picture.
* Add peak+loudness post-normalization to AceStepPipeline
The real pipeline normalizes audio in two stages (see
acestep/audio_utils.py:72 normalize_audio + generate_music_decode.py):
1. if peak > 1: audio /= peak (anti-clip)
2. audio *= target_amp / peak (target_amp = 10 ** (-1/20) ~ 0.891)
Step 2 is loudness normalization to -1 dBFS. Without it diffusers outputs
had peak=1.0 vs the real 0.891 — same music content (pearson was ~0.86
already), just 1.12x louder. Add step 2 after the existing anti-clip step.
* Match acestep/inference.py inference_steps=8 for ALL variants
GenerationParams.inference_steps default is 8 — turbo AND base/SFT. I had
base/SFT defaulting to 27 here, so every base/SFT parity run was comparing
a 27-step diffusers trajectory against an 8-step real trajectory. Different
number of denoising steps means different audio even at fixed seed.
This likely explains the lower base/SFT correlation in my earlier jieyue
runs (turbo was 0.86, base/SFT were 0.32-0.34). Aligning step counts
should bring base/SFT closer to turbo parity.
* Address PR #13095 review: rename classes + reuse diffusers primitives
Response to dg845's PR comments batch 1+2. DiT parity harness still bit-identical
(max_abs=0 on fp32 / SDPA across 4 shape cases).
Transformer file:
* Rename AceStepDiTModel -> AceStepTransformer1DModel (alias kept).
* Rename AceStepDiTLayer -> AceStepTransformerBlock (alias kept).
* Inherit AttentionMixin + CacheMixin on the DiT model.
* Swap in diffusers.models.normalization.RMSNorm for the hand-rolled
AceStepRMSNorm (weight-key-compatible).
* Swap the hand-rolled rotary embedding + apply_rotary for diffusers'
get_1d_rotary_pos_embed + apply_rotary_emb (use_real_unbind_dim=-2 to
match the cat-half convention ACE-Step inherits from Qwen3).
* Use get_timestep_embedding with flip_sin_to_cos=True — keeps the
(cos, sin) ordering of the original sinusoidal. State-dict-compatible.
* Drop max_position_embeddings arg from DiT config (RoPE computes freqs
per call based on seq_len); converter drops it.
* Gradient-checkpoint call now takes just the layer module (matches the
Flux2 idiom).
Pipeline modeling file (pipelines/ace_step/modeling_ace_step.py):
* Moved _pack_sequences + AceStepEncoderLayer here — they aren't used
by the DiT, so they shouldn't live in the transformer file.
* AceStepLyricEncoder + AceStepTimbreEncoder set
_supports_gradient_checkpointing = True and wrap encoder-layer calls
through the checkpointing func when enabled.
* Use diffusers RMSNorm + the RoPE helper from the transformer file
(shared single implementation).
Converter (scripts/convert_ace_step_to_diffusers.py):
* model_index.json now carries AceStepTransformer1DModel.
* Drop max_position_embeddings / use_sliding_window from the emitted
configs.
No numerical regressions: scripts/dit_parity_test.py PASSES with
max_abs=0.0 on fp32/SDPA across short, long, batched, and
padding-path shape variants.
* Address PR #13095 review: pipeline polish + converter HF-hub support
Response to dg845 review comments on the pipeline side. DiT parity still
bit-identical (max_abs=0 across 4 shape cases).
Pipeline (pipelines/ace_step/pipeline_ace_step.py):
* Add `sample_rate` + `latents_per_second` properties sourced from the
VAE config so the pipeline no longer hardcodes 48000 / 25 / 1920.
Propagates through prepare_latents, chunk_mask window math, and the
audio-duration round-trip.
* Add `do_classifier_free_guidance` property (matches LTX2 et al.).
* Add `check_inputs(...)` called from `__call__` before allocating noise.
Validates prompt type, lyrics type, task_type, step count, guidance
scale, shift, cfg interval bounds and repaint window ordering.
* Add `callback_on_step_end` + `callback_on_step_end_tensor_inputs` —
the modern callback form. The legacy `callback` / `callback_steps`
pair is kept for back-compat. Setting `pipe._interrupt = True` inside
the callback stops the loop early.
* Expose `encode_audio(audio)` as a public helper that wraps the tiled
VAE encode + (B, T, D) transpose the pipeline performs internally.
Converter (scripts/convert_ace_step_to_diffusers.py):
* Accept a Hugging Face Hub repo id for `--checkpoint_dir`; resolves it
via `huggingface_hub.snapshot_download` when the argument isn't a
local path.
Exports:
* Register `AceStepTransformer1DModel` in the top-level __init__,
models/__init__, models/transformers/__init__, and dummy_pt_objects so
`from diffusers import AceStepTransformer1DModel` works and the
pipeline loader resolves the new class name from model_index.json.
Deferred for a follow-up (commented inline in the PR): full
`Attention + AttnProcessor + dispatch_attention_fn` refactor and
`FlowMatchEulerDiscreteScheduler` migration — both would benefit from a
dedicated parity re-run and review.
* Fix stale ACE-Step 1.0-era docs / class names in the 1.5 integration
Docs and docstrings still carried a mix of 1.0 paper title, non-existent
`ACE-Step/ACE-Step-v1-5-turbo` hub id, `shift=3.0` turbo default, and
the old `AceStepDiTModel` class name. Cleaned up to match the actual
1.5 release:
* pipelines/ace_step.md: correct citation title ("ACE-Step 1.5: Pushing
the Boundaries of Open-Source Music Generation"), correct repo
(`ace-step/ACE-Step-1.5`), new variants table with real HF ids
(`Ace-Step1.5` / `acestep-v15-base` / `acestep-v15-sft`) and their
per-variant step/CFG defaults, drop the wrong `shift=3.0` tip.
* models/ace_step_transformer.md: page renamed to
`AceStepTransformer1DModel` with a short 1.5-specific description;
`AceStepDiTModel` noted as a backwards-compat alias.
* pipeline_ace_step.py: import, docstring, `Args`, and `__init__`
annotation reference `AceStepTransformer1DModel`; example model id
now `ACE-Step/Ace-Step1.5`; `_variant_defaults` docstring and the
`__call__` variant-fallback comment no longer claim `shift=3.0` /
`27 steps` — real defaults are 8 steps / shift=1.0 across all
variants, guidance=1.0 (turbo) vs 7.0 (base+sft).
* Address PR #13095 review: VAE tiling on AutoencoderOobleck + Timesteps class
Two more deferred review threads from dg845 addressed:
* Move tiled encode/decode onto AutoencoderOobleck
(https://github.com/huggingface/diffusers/pull/13095#discussion_r2785513647).
AutoencoderOobleck now carries `use_tiling` + `tile_sample_min_length` /
`tile_sample_overlap` / `tile_latent_min_length` / `tile_latent_overlap`
attributes and private `_tiled_encode` / `_tiled_decode` methods; the
existing `encode` / `_decode` dispatch to them when tiling is enabled and
the input exceeds the threshold. `AutoencoderMixin.enable_tiling()` is
already inherited.
AceStepPipeline's private `_tiled_encode` / `_tiled_decode` and the
`use_tiled_decode` `__call__` arg are gone; `__init__` now calls
`self.vae.enable_tiling()` so the long-audio memory behaviour is preserved
by default. Users can opt out with `pipe.vae.disable_tiling()`.
Note: the VAE-side tiling concatenates encoder features (h) and samples
the posterior once, instead of the old per-tile `.sample()` calls. This
is the standard diffusers pattern; numerically differs only in the
structure of the noise across tile boundaries.
* Use the Timesteps nn.Module for the sinusoid
(https://github.com/huggingface/diffusers/pull/13095#discussion_r2785420234).
`AceStepTimestepEmbedding` wraps `Timesteps(in_channels, flip_sin_to_cos=
True, downscale_freq_shift=0)` instead of calling `get_timestep_embedding`
directly — reviewer asked for the Module form.
* Address PR #13095 review: refactor AceStepAttention to Attention + AttnProcessor
Splits the monolithic AceStepAttention into the diffusers standard
Attention + AttnProcessor layout:
- AceStepAttention (torch.nn.Module, AttentionModuleMixin) holds the
to_q/to_k/to_v/to_out projections and norm_q/norm_k RMSNorms.
- AceStepAttnProcessor2_0 runs the attention dispatch through
dispatch_attention_fn so users can pick flash / sage / native backends
via model.set_attention_backend(...) or the attention_backend context
manager.
GQA (Q has 16 heads / K,V have 8) is preserved by passing enable_gqa=True
to dispatch_attention_fn instead of repeat_interleave; fusion is disabled
(_supports_qkv_fusion = False) because Q and K,V have different output
sizes.
The converter is updated to rename the six attention sub-keys
(q_proj -> to_q, k_proj -> to_k, v_proj -> to_v, o_proj -> to_out.0,
q_norm -> norm_q, k_norm -> norm_k) on both the DiT decoder path and the
condition encoder path, since AceStepLyricEncoder / AceStepTimbreEncoder
share the same AceStepAttention class.
Addresses review comments r2785433213 and r2785450463.
* Address PR #13095 review: migrate to FlowMatchEulerDiscreteScheduler
Replace the hand-rolled flow-matching Euler loop with
`FlowMatchEulerDiscreteScheduler`. ACE-Step still computes its own shifted /
turbo sigma schedule via `_get_timestep_schedule`, but now passes it to
`scheduler.set_timesteps(sigmas=...)` and delegates the ODE step to
`scheduler.step()`. The scheduler is configured with `num_train_timesteps=1`
and `shift=1.0` so `scheduler.timesteps` stays in `[0, 1]` (the convention the
DiT was trained on) and the scheduler doesn't re-shift already-shifted sigmas.
The scheduler's appended terminal `sigma=0` reproduces the old loop's
final-step "project to x0" case exactly: `prev = x + (0 - t_curr) * v`.
Parity on jieyue (seed=42, bf16 + flash-attn, turbo text2music, 8 steps):
waveform Pearson = 0.999999
spectral Pearson = 1.000000
max |diff| = 2.5e-3 (fp32 step-math vs previous bf16 step-math)
fp32 Euler-loop A/B against the hand-rolled path: max |diff| = 3.6e-7.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* Address PR #13095 review: move DiT tests + drop stale test kwargs
- Move the DiT transformer tests out of the pipeline test file into a new
tests/models/transformers/test_models_transformer_ace_step.py that follows
the standard BaseModelTesterConfig + ModelTesterMixin scaffold (matches
test_models_transformer_longcat_audio_dit.py).
- Drop `max_position_embeddings` from the remaining AceStepDiTModel and
AceStepConditionEncoder test fixtures — neither constructor accepts that
argument anymore.
- Drop `use_sliding_window` from the same fixtures — also no longer a
constructor argument (the actual `sliding_window` int kwarg is kept).
- Wire `FlowMatchEulerDiscreteScheduler(num_train_timesteps=1, shift=1.0)`
into `get_dummy_components()` now that the pipeline requires it.
Resolves https://github.com/huggingface/diffusers/pull/13095#discussion_r3115653554,
r3115664850, r3115673059, r3115676580, r3115680700.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* Address PR #13095 review from dg845 (2026-04-23)
Fixes 5 review threads + style:
1. Converter now builds `AceStepPipeline` in memory and calls
`save_pretrained`. Previously the hand-written `model_index.json` was
missing the `scheduler` entry — fresh converter output couldn't be loaded
by `AceStepPipeline.from_pretrained` (r3127767785). This also makes the
converter robust to future `__init__` signature changes.
2. `latent_length` uses `math.ceil(...)` instead of `int(...)` so non-integer
products (e.g. `latents_per_second=2.0, audio_duration=0.4 → 0.8`) round up
to `1` instead of truncating to `0` and crashing shape checks (r3127790939).
3. Add `_callback_tensor_inputs = ["latents"]` on `AceStepPipeline` so the
standard diffusers callback tests pick up the right tensor (r3127795954).
4. `AceStepConditionEncoder.silence_latent` no longer hard-codes the channel
dim to 64. The placeholder buffer now uses the `timbre_hidden_dim`
constructor argument, so smaller test configs with `timbre_hidden_dim != 64`
load without shape errors (r3127812932).
5. Revert `self.vae.enable_tiling()` from `AceStepPipeline.__init__`. Users can
call `pipe.vae.enable_tiling()` themselves for long-form generation; that
matches the opt-in convention used by the rest of diffusers (r3127777296).
6. `ruff check --fix` + `ruff format` over all ACE-Step sources (the style fix
dg845 asked for via `@bot /style`).
Also: converter now accepts sharded `model.safetensors.index.json` layouts
alongside the single-file `model.safetensors`, so the 5B XL turbo variant
converts without a pre-processing step.
Parity on jieyue (seed=42, bf16 + flash-attn, turbo text2music 160s, fresh
converter output loaded via `from_pretrained`):
waveform Pearson = 0.999954
spectral Pearson = 0.999977
max |a-b| bf16 = 4.3e-02 (dominated by the VAE tiling default flip)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* Address PR #13095 review from yiyixuxu (2026-04-23)
Code-level (22 threads):
1. Delete 3 dev/parity scripts (`scripts/audio_parity_jieyue.py`,
`scripts/dit_parity_test.py`, `scripts/run_official_generate_music.py`)
that shouldn't have been committed.
2. Rename `AutoencoderOobleck._encode_one` → `_encode` to match the convention
used by other diffusers VAEs.
3. Delete the hard-coded `SHIFT_TIMESTEPS` / `VALID_SHIFTS` table in
`pipeline_ace_step.py`: the per-shift turbo schedules are recovered
exactly by `linspace(1, 0, N+1)[:-1]` plus the flow-match shift formula
that the non-turbo branch already uses, so a single code path covers both.
4. Drop the backwards-compat `AceStepDiTModel` / `AceStepDiTLayer` aliases
and every reference (top-level `__init__`, `models/__init__`,
`transformers/__init__`, dummy objects, tests, docs toctree, model card).
`AceStepTransformer1DModel` is the only exported name now.
5. Remove the unused `attention_mask` / `encoder_attention_mask` args from
`AceStepTransformer1DModel.forward`; the model rebuilds its masks from
the sequence shape and never consumed them.
6. In the DiT forward and both encoders, pass `None` instead of an all-zero
`full_attn_mask` / `encoder_4d_mask` to non-sliding attention layers — SDPA
dispatches to a faster kernel when the mask is None.
7. Inline the shared `_run_encoder_layers` helper directly into
`AceStepLyricEncoder.forward` / `AceStepTimbreEncoder.forward` so layer
calls are visible at the forward boundary (diffusers style).
8. Move `is_turbo` / `sample_rate` / `latents_per_second` from `@property`s
that re-read module configs each call to cached attributes populated in
`__init__` (Flux2-style), with a default-ACE-Step fallback when
`self.vae` is offloaded. Drop the now-unused `SAMPLE_RATE = 48000`
module-level constant and the three property definitions.
9. Warn + coerce `guidance_scale` to 1.0 on turbo (guidance-distilled)
checkpoints, following `pipeline_flux2_klein`. Prevents over-guided
audio when users forward their base/sft CFG settings to a turbo pipe.
10. Remove the `logger.warning(...)` paths that triggered on
`silence_latent` missing/zero — those only fired for author-side
unconverted checkpoints and tests; end users always load converted
weights where the buffer is baked in.
11. Drop the redundant `with torch.no_grad():` wrappers inside
`encode_prompt` — the pipeline's `__call__` runs under `torch.no_grad`
already.
12. Strip "reviewer comment on PR #13095" attribution comments from three
docstrings (here and everywhere).
Parity on jieyue (seed=42, bf16 + flash-attn, XL turbo 160s text2music):
waveform Pearson = 0.9747
spectral Pearson = 0.9895
The shift comes from full-attention layers switching `attn_mask=0_tensor` →
`attn_mask=None`, which dispatches to a different SDPA kernel on bf16. The
two outputs are algebraically equivalent for fp32 eager; on bf16+FA the
delta is dominated by kernel-level ULPs, well within the sampler-noise
band (ear-check on the 160s example confirms no audible regression).
Still open — AudioTokenizer/Detokenizer (deferred) + APG guider follow-up
(dims differ from `diffusers.guiders.adaptive_projected_guidance`, not a
drop-in; worth a separate PR).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* Address ACE-Step audio token and APG review
* Fix ACE-Step docs CI
* Address ACE-Step pipeline cleanup review
* Fix ACE-Step flash attention sliding windows
* Add ACE-Step callback properties
* Address ACE-Step final review comments
---------
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: YiYi Xu <yixu310@gmail.com>
Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>
🤗 Diffusers is the go-to library for state-of-the-art pretrained diffusion models for generating images, audio, and even 3D structures of molecules. Whether you're looking for a simple inference solution or training your own diffusion models, 🤗 Diffusers is a modular toolbox that supports both. Our library is designed with a focus on usability over performance, simple over easy, and customizability over abstractions.
🤗 Diffusers offers three core components:
- State-of-the-art diffusion pipelines that can be run in inference with just a few lines of code.
- Interchangeable noise schedulers for different diffusion speeds and output quality.
- Pretrained models that can be used as building blocks, and combined with schedulers, for creating your own end-to-end diffusion systems.
Installation
We recommend installing 🤗 Diffusers in a virtual environment from PyPI or Conda. For more details about installing PyTorch, please refer to their official documentation.
PyTorch
With pip (official package):
pip install --upgrade diffusers[torch]
With conda (maintained by the community):
conda install -c conda-forge diffusers
Apple Silicon (M1/M2) support
Please refer to the How to use Stable Diffusion in Apple Silicon guide.
Quickstart
Generating outputs is super easy with 🤗 Diffusers. To generate an image from text, use the from_pretrained method to load any pretrained diffusion model (browse the Hub for 30,000+ checkpoints):
from diffusers import DiffusionPipeline
import torch
pipeline = DiffusionPipeline.from_pretrained("stable-diffusion-v1-5/stable-diffusion-v1-5", torch_dtype=torch.float16)
pipeline.to("cuda")
pipeline("An image of a squirrel in Picasso style").images[0]
You can also dig into the models and schedulers toolbox to build your own diffusion system:
from diffusers import DDPMScheduler, UNet2DModel
from PIL import Image
import torch
scheduler = DDPMScheduler.from_pretrained("google/ddpm-cat-256")
model = UNet2DModel.from_pretrained("google/ddpm-cat-256").to("cuda")
scheduler.set_timesteps(50)
sample_size = model.config.sample_size
noise = torch.randn((1, 3, sample_size, sample_size), device="cuda")
input = noise
for t in scheduler.timesteps:
with torch.no_grad():
noisy_residual = model(input, t).sample
prev_noisy_sample = scheduler.step(noisy_residual, t, input).prev_sample
input = prev_noisy_sample
image = (input / 2 + 0.5).clamp(0, 1)
image = image.cpu().permute(0, 2, 3, 1).numpy()[0]
image = Image.fromarray((image * 255).round().astype("uint8"))
image
Check out the Quickstart to launch your diffusion journey today!
How to navigate the documentation
| Documentation | What can I learn? |
|---|---|
| Tutorial | A basic crash course for learning how to use the library's most important features like using models and schedulers to build your own diffusion system, and training your own diffusion model. |
| Loading | Guides for how to load and configure all the components (pipelines, models, and schedulers) of the library, as well as how to use different schedulers. |
| Pipelines for inference | Guides for how to use pipelines for different inference tasks, batched generation, controlling generated outputs and randomness, and how to contribute a pipeline to the library. |
| Optimization | Guides for how to optimize your diffusion model to run faster and consume less memory. |
| Training | Guides for how to train a diffusion model for different tasks with different training techniques. |
Contribution
We ❤️ contributions from the open-source community! If you want to contribute to this library, please check out our Contribution guide. You can look out for issues you'd like to tackle to contribute to the library.
- See Good first issues for general opportunities to contribute
- See New model/pipeline to contribute exciting new diffusion models / diffusion pipelines
- See New scheduler
Also, say 👋 in our public Discord channel . We discuss the hottest trends about diffusion models, help each other with contributions, personal projects or just hang out ☕.
Popular Tasks & Pipelines
| Task | Pipeline | 🤗 Hub |
|---|---|---|
| Unconditional Image Generation | DDPM | google/ddpm-ema-church-256 |
| Text-to-Image | Stable Diffusion Text-to-Image | stable-diffusion-v1-5/stable-diffusion-v1-5 |
| Text-to-Image | unCLIP | kakaobrain/karlo-v1-alpha |
| Text-to-Image | DeepFloyd IF | DeepFloyd/IF-I-XL-v1.0 |
| Text-to-Image | Kandinsky | kandinsky-community/kandinsky-2-2-decoder |
| Text-guided Image-to-Image | ControlNet | lllyasviel/sd-controlnet-canny |
| Text-guided Image-to-Image | InstructPix2Pix | timbrooks/instruct-pix2pix |
| Text-guided Image-to-Image | Stable Diffusion Image-to-Image | stable-diffusion-v1-5/stable-diffusion-v1-5 |
| Text-guided Image Inpainting | Stable Diffusion Inpainting | stable-diffusion-v1-5/stable-diffusion-inpainting |
| Image Variation | Stable Diffusion Image Variation | lambdalabs/sd-image-variations-diffusers |
| Super Resolution | Stable Diffusion Upscale | stabilityai/stable-diffusion-x4-upscaler |
| Super Resolution | Stable Diffusion Latent Upscale | stabilityai/sd-x2-latent-upscaler |
Popular libraries using 🧨 Diffusers
- https://github.com/microsoft/TaskMatrix
- https://github.com/invoke-ai/InvokeAI
- https://github.com/InstantID/InstantID
- https://github.com/apple/ml-stable-diffusion
- https://github.com/Sanster/lama-cleaner
- https://github.com/IDEA-Research/Grounded-Segment-Anything
- https://github.com/ashawkey/stable-dreamfusion
- https://github.com/deep-floyd/IF
- https://github.com/bentoml/BentoML
- https://github.com/bmaltais/kohya_ss
- +14,000 other amazing GitHub repositories 💪
Thank you for using us ❤️.
Credits
This library concretizes previous work by many different authors and would not have been possible without their great research and implementations. We'd like to thank, in particular, the following implementations which have helped us in our development and without which the API could not have been as polished today:
- @CompVis' latent diffusion models library, available here
- @hojonathanho original DDPM implementation, available here as well as the extremely useful translation into PyTorch by @pesser, available here
- @ermongroup's DDIM implementation, available here
- @yang-song's Score-VE and Score-VP implementations, available here
We also want to thank @heejkoo for the very helpful overview of papers, code and resources on diffusion models, available here as well as @crowsonkb and @rromb for useful discussions and insights.
Citation
@misc{von-platen-etal-2022-diffusers,
author = {Patrick von Platen and Suraj Patil and Anton Lozhkov and Pedro Cuenca and Nathan Lambert and Kashif Rasul and Mishig Davaadorj and Dhruv Nair and Sayak Paul and William Berman and Yiyi Xu and Steven Liu and Thomas Wolf},
title = {Diffusers: State-of-the-art diffusion models},
year = {2022},
publisher = {GitHub},
journal = {GitHub repository},
howpublished = {\url{https://github.com/huggingface/diffusers}}
}
