unsloth/studio/backend/core/inference/video.py
Daniel Han d442e00407 Scope the video base repo download to the files the pipeline loads
A bare from_pretrained snapshot of Lightricks/LTX-2 pulls the whole 314 GB
repo: 170 GB of packaged root checkpoints and a second 50 GB text-encoder
shard set, when the pipeline reads about 93 GB. Build the needed file list
once (shared with the progress estimate so the two cannot disagree),
download it per file with cancellation, and hand from_pretrained the local
snapshot dir. Clamp the progress counter to the estimate so stale cache
blobs can no longer report over 100 percent.
2026-07-05 03:17:55 +00:00

1015 lines
43 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""Local text-to-video inference backend (diffusers).
A deliberate sibling of ``DiffusionBackend`` rather than a mode of it: video
pipelines take frame/fps arguments, return frame stacks (plus synchronized audio
for LTX-2) instead of PIL images, and persist MP4s -- none of the image module's
img2img/inpaint/ControlNet/LoRA surface applies. The concurrency skeleton
(load token, per-generation cancel event, split status/generate locks) is copied
from the image backend so the two cannot diverge in lifecycle behaviour, and the
hardware/optimisation layers are IMPORTED from the image stack unchanged:
device/dtype resolution, memory planning + offload tiers, attention backends,
speed profiles (regional torch.compile), and FBCache step caching all operate on
``pipe.transformer`` generically.
Video-specific behaviour lives here:
- the runtime headroom estimate is frames-aware (``estimate_video_runtime_mib``):
the VAE decode of a whole clip is the memory peak, not the denoise;
- VAE tiling is always enabled (decode of 100+ frames at 720p-class resolutions
spikes far beyond the image case, and tiling's quality cost is negligible);
- generation snaps num_frames to the family's temporal lattice (k * step + 1)
and width/height to its required multiple BEFORE latents are allocated;
- the result is encoded to MP4 (H.264) via diffusers' PyAV-backed exporter,
muxing the audio track for families that produce one.
Loads are gated to trusted repos exactly like the image backend: unsloth/*, the
family's official base repos, or a local path the user explicitly picked.
"""
from __future__ import annotations
import inspect
import os
import tempfile
import threading
import time
from dataclasses import dataclass
from pathlib import Path
from typing import Any, Optional
from loggers import get_logger
from .diffusion_attention import apply_attention_backend, select_attention_backend
from .diffusion_cache import apply_step_cache, normalize_transformer_cache
from .diffusion_device import resolve_diffusion_device_target
from .diffusion_memory import (
apply_memory_plan,
estimate_gguf_resident_mib,
estimate_safetensors_dense_mib,
estimate_video_runtime_mib,
file_size_mib,
normalize_memory_mode,
plan_diffusion_memory,
snapshot_device_memory,
)
from .diffusion_speed import (
SPEED_OFF,
apply_speed_optims,
resolve_speed_mode,
restore_backend_flags,
snapshot_backend_flags,
)
from .diffusion_auto_policy import build_resolved_record
from .video_families import (
VIDEO_CANCELLED_MSG,
VIDEO_NOT_LOADED_MSG,
VideoFamily,
default_video_generation_params,
detect_video_family,
resolve_video_base_repo,
snap_num_frames,
snap_video_size,
supported_video_family_names,
)
from utils.hardware import clear_gpu_cache
logger = get_logger(__name__)
# Load kinds, mirroring the image backend: "gguf" (single-file GGUF DiT +
# companion base repo), "single_file" (safetensors DiT, e.g. the fp8 LTX-2.3
# checkpoints), "pipeline" (a full diffusers repo via from_pretrained).
_MODEL_KINDS = frozenset({"gguf", "single_file", "pipeline"})
# Official vendor base repos allowed to load as full (non-GGUF) artifacts even
# though they are not under unsloth/. Exact-match, lowercased, safetensors-only,
# no remote code -- same bar as the image backend's allowlist.
_TRUSTED_NON_GGUF_VIDEO_REPOS = frozenset(
{
"lightricks/ltx-2",
"lightricks/ltx-2.3",
"lightricks/ltx-2.3-fp8",
}
)
def resolve_video_model_kind(gguf_filename: Optional[str], model_kind: Optional[str]) -> str:
"""Classify a load request; explicit model_kind wins, else the filename decides."""
if model_kind:
kind = model_kind.strip().lower()
if kind not in _MODEL_KINDS:
raise ValueError(
f"Unknown model_kind '{model_kind}'. Expected one of {sorted(_MODEL_KINDS)}."
)
return kind
if not gguf_filename:
return "pipeline"
return "gguf" if gguf_filename.strip().lower().endswith(".gguf") else "single_file"
def _is_trusted_video_repo(repo_id: str) -> bool:
"""Whether a NON-GGUF load may deserialise this repo (see the image twin)."""
try:
if Path(repo_id).expanduser().exists():
return True
except OSError:
pass
rid = repo_id.strip().lower()
return rid.startswith("unsloth/") or rid in _TRUSTED_NON_GGUF_VIDEO_REPOS
def _ensure_mp4_encoder_available() -> None:
"""Fail a load fast when PyAV is missing: the export otherwise dies AFTER a
multi-minute denoise, which is the worst possible time to learn about it."""
try:
import av # noqa: F401
except Exception as exc: # noqa: BLE001 -- any import failure means no encoder
raise ValueError(
"Video generation needs the 'av' package (PyAV) to encode MP4s. "
"Install it with: pip install av"
) from exc
@dataclass(frozen = True)
class _VideoLoadState:
"""Everything about the currently-loaded video pipeline, swapped as one unit."""
pipe: Any
family: VideoFamily
repo_id: str
base_repo: str
device: str
dtype: str
kind: str
gguf_filename: Optional[str] = None
offload_policy: str = "none"
vae_tiling: bool = True
memory_mode: str = "auto"
speed_mode: str = SPEED_OFF
speed_optims: tuple = ()
backend_flags: Optional[dict] = None
attention_backend: Optional[str] = None
transformer_cache: Optional[str] = None
resolved: Optional[dict] = None
@dataclass
class _VideoLoadingState:
repo_id: str
base_repo: str
expected_bytes: Optional[int] = None
error: Optional[str] = None
def _progress(phase: Optional[str], **extra: Any) -> dict[str, Any]:
return {"phase": phase, **extra}
class VideoBackend:
"""One loaded video pipeline; loads swap it atomically (same model as images)."""
def __init__(self) -> None:
self._lock = threading.Lock()
self._generate_lock = threading.Lock()
self._state: Optional[_VideoLoadState] = None
self._loading: Optional[_VideoLoadingState] = None
self._load_token = 0
self._cancel_event = threading.Event()
self._active_generate_cancel: Optional[threading.Event] = None
# Generation progress, written by the step callback / phase transitions.
self._gen: dict[str, Any] = {"active": False}
# ── validation ───────────────────────────────────────────────────────────
def validate_load_request(
self,
repo_id: str,
*,
gguf_filename: Optional[str] = None,
base_repo: Optional[str] = None,
family_override: Optional[str] = None,
model_kind: Optional[str] = None,
) -> VideoFamily:
"""Cheap, network-free validation shared by the route and the load path."""
kind = resolve_video_model_kind(gguf_filename, model_kind)
fam = detect_video_family(repo_id, family_override) or (
detect_video_family(f"{repo_id}/{gguf_filename}")
if gguf_filename and not family_override
else None
)
if fam is None:
raise ValueError(
f"'{repo_id}' is not a supported text-to-video model. Supported families: "
f"{', '.join(supported_video_family_names())}. If this is a variant of one "
f"of them, pass family_override with that family name."
)
if kind != "gguf" and not _is_trusted_video_repo(repo_id):
raise ValueError(
f"Non-GGUF video loads are limited to unsloth/* repos, the official "
f"family base repos, and local paths; '{repo_id}' is neither."
)
# The companions load with from_pretrained too, so an explicit base repo is
# held to the same bar as a non-GGUF repo id: a GGUF pick must not smuggle
# in an arbitrary remote base.
if base_repo and (base_repo or "").strip() and not _is_trusted_video_repo(base_repo):
raise ValueError(
f"base_repo is limited to unsloth/* repos, the official family base "
f"repos, and local paths; '{base_repo}' is neither."
)
if kind in ("gguf", "single_file") and not gguf_filename:
raise ValueError("A gguf/single_file load needs the checkpoint filename.")
# A local checkpoint that cannot exist must fail HERE, before the route evicts
# a resident chat/image model for a load that dies at resolve time.
if kind in ("gguf", "single_file"):
root = Path(repo_id).expanduser()
if root.is_dir():
from .diffusion_families import resolve_local_gguf_child
try:
resolve_local_gguf_child(root, gguf_filename or "")
except Exception as exc: # noqa: BLE001 -- surface as client input error
raise ValueError(str(exc)) from exc
elif repo_id.startswith(("/", "~", "./", "../")) and not root.is_file():
raise ValueError(f"Local model path '{repo_id}' does not exist.")
_ensure_mp4_encoder_available()
return fam
# ── background load + progress ───────────────────────────────────────────
def begin_load(
self,
repo_id: str,
*,
gguf_filename: Optional[str] = None,
base_repo: Optional[str] = None,
family_override: Optional[str] = None,
hf_token: Optional[str] = None,
memory_mode: Optional[str] = None,
speed_mode: Optional[str] = None,
attention_backend: Optional[str] = None,
transformer_cache: Optional[str] = None,
transformer_cache_threshold: Optional[float] = None,
model_kind: Optional[str] = None,
) -> dict[str, Any]:
"""Validate, then run the (slow) load on a daemon thread. Returns at once."""
hf_token = (hf_token.strip() if isinstance(hf_token, str) else hf_token) or None
fam = self.validate_load_request(
repo_id,
gguf_filename = gguf_filename,
base_repo = base_repo,
family_override = family_override,
model_kind = model_kind,
)
with self._lock:
if self._loading is not None and self._loading.error is None:
raise RuntimeError("A video load is already in progress.")
self._load_token += 1
token = self._load_token
self._cancel_event.clear()
self._loading = _VideoLoadingState(repo_id = repo_id, base_repo = fam.base_repo)
threading.Thread(
target = self._run_load,
kwargs = dict(
repo_id = repo_id,
gguf_filename = gguf_filename,
base_repo = base_repo,
family_override = family_override,
hf_token = hf_token,
memory_mode = memory_mode,
speed_mode = speed_mode,
attention_backend = attention_backend,
transformer_cache = transformer_cache,
transformer_cache_threshold = transformer_cache_threshold,
model_kind = model_kind,
_load_token = token,
),
daemon = True,
).start()
return self.status()
def _run_load(self, **kwargs: Any) -> None:
token = kwargs.get("_load_token")
try:
fam = detect_video_family(kwargs["repo_id"], kwargs.get("family_override"))
kind = resolve_video_model_kind(kwargs.get("gguf_filename"), kwargs.get("model_kind"))
base = (
kwargs["repo_id"]
if kind == "pipeline"
else resolve_video_base_repo(fam, kwargs.get("base_repo"))
)
kwargs["base_repo"] = base
expected = self._estimate_download_bytes(
kwargs["repo_id"], kwargs.get("gguf_filename"), base, kwargs.get("hf_token"), kind
)
with self._lock:
if self._load_token == token and self._loading is not None:
self._loading.base_repo = base
self._loading.expected_bytes = expected
# The GGUF/single-file checkpoint downloads outside the lock so an
# unload/eviction can preempt the multi-GB pull; the pipeline
# companions pre-download the same way (scoped file list, cancellable,
# resumes from the cache so a cancelled pull costs nothing).
if kwargs.get("gguf_filename") and not Path(kwargs["repo_id"]).expanduser().exists():
from utils.hf_xet_fallback import hf_hub_download_with_xet_fallback
hf_hub_download_with_xet_fallback(
kwargs["repo_id"],
kwargs["gguf_filename"],
kwargs.get("hf_token"),
cancel_event = self._cancel_event,
)
kwargs["_base_local_dir"] = self._predownload_base(
base, kwargs.get("hf_token"), kind
)
self.load_pipeline(**kwargs)
with self._lock:
if self._load_token == token:
self._loading = None
except Exception as exc: # noqa: BLE001 -- surfaced via load_progress
if self._load_token != token:
return
logger.error("video.load_failed: %s", exc)
from utils.native_path_leases import redact_native_paths
with self._lock:
if self._load_token == token and self._loading is not None:
self._loading.error = redact_native_paths(str(exc))
@staticmethod
def _base_download_files(info: Any, kind: str) -> list[tuple[str, int]]:
"""The (rfilename, size) list a load actually needs from the base repo.
Single source of truth for the progress estimate AND the scoped pre-download,
so the two can never disagree. Excluded on purpose:
- root-level packaged checkpoints (ComfyUI-style singles; 170 GB of the LTX-2
repo) -- the diffusers pipeline only reads per-component subfolders;
- the duplicate ``text_encoder/diffusion_pytorch_model*`` shard set (the LTX-2
base repo ships its text encoder twice; transformers loads the ``model-*``
naming via the shard index);
- ``transformer/`` when a GGUF/single-file checkpoint replaces the DiT."""
files: list[tuple[str, int]] = []
for sibling in info.siblings or []:
name, size = sibling.rfilename, sibling.size or 0
if not name.endswith((".safetensors", ".json", ".model", ".txt")):
continue
if "/" not in name and name.endswith(".safetensors"):
continue
if kind != "pipeline" and name.startswith("transformer/"):
continue
if name.startswith("text_encoder/diffusion_pytorch_model"):
continue
files.append((name, int(size)))
return files
def _estimate_download_bytes(
self,
repo_id: str,
gguf_filename: Optional[str],
base: str,
hf_token: Optional[str],
kind: str,
) -> Optional[int]:
"""Total bytes this load will pull (checkpoint + companions), or None."""
try:
from huggingface_hub import HfApi
total = 0
api = HfApi(token = hf_token or None)
if gguf_filename and not Path(repo_id).expanduser().exists():
info = api.model_info(repo_id, files_metadata = True)
for sibling in info.siblings or []:
if sibling.rfilename == gguf_filename and sibling.size:
total += int(sibling.size)
if base and not Path(base).expanduser().exists():
info = api.model_info(base, files_metadata = True)
total += sum(size for _, size in self._base_download_files(info, kind))
return total or None
except Exception: # noqa: BLE001 -- progress totals are best-effort only
return None
def _predownload_base(self, base: str, hf_token: Optional[str], kind: str) -> Optional[str]:
"""Pull exactly the base-repo files the load needs; return the local snapshot dir.
A bare ``from_pretrained(repo_id)`` snapshot of Lightricks/LTX-2 downloads the
whole 314 GB repo (root packaged checkpoints plus a second 50 GB text-encoder
shard set) when ~93 GB is used. Downloading the scoped file list ourselves is
also cancellable per file, and handing the local dir to from_pretrained skips
diffusers' own expected-files sweep. None -> caller keeps the hub id (local
path, non-diffusers layout, or any metadata failure: from_pretrained then
resolves the repo exactly as before)."""
try:
if not base or Path(base).expanduser().exists():
return None
from huggingface_hub import HfApi
info = HfApi(token = hf_token or None).model_info(base, files_metadata = True)
files = self._base_download_files(info, kind)
if not any(name == "model_index.json" for name, _ in files):
return None
from utils.hf_xet_fallback import hf_hub_download_with_xet_fallback
snapshot_root: Optional[Path] = None
for name, _ in files:
local = Path(
hf_hub_download_with_xet_fallback(
base, name, hf_token, cancel_event = self._cancel_event
)
)
if name == "model_index.json":
snapshot_root = local.parent
return str(snapshot_root) if snapshot_root is not None else None
except Exception as exc: # noqa: BLE001 -- fall back to from_pretrained's own pull
if self._cancel_event.is_set():
raise
logger.warning("video.predownload_fallback: %s", exc)
return None
def _cache_bytes(self, repo_id: Optional[str]) -> int:
"""Bytes of ``repo_id`` currently in the HF blob cache (progress polling)."""
if not repo_id:
return 0
try:
from huggingface_hub import scan_cache_dir
rid = repo_id.strip()
for repo in scan_cache_dir().repos:
if repo.repo_id == rid:
return int(repo.size_on_disk)
except Exception: # noqa: BLE001 -- cache scan is best-effort
return 0
return 0
def load_progress(self) -> dict[str, Any]:
"""Phase + downloaded/total bytes for the in-flight load (cache-scan based)."""
loading = self._loading
if loading is not None and loading.error:
return _progress("error", error = loading.error)
if loading is None:
return _progress("ready" if self._state is not None else None)
downloaded = self._cache_bytes(loading.repo_id)
if loading.base_repo and loading.base_repo != loading.repo_id:
downloaded += self._cache_bytes(loading.base_repo)
expected = loading.expected_bytes
phase = "downloading"
if expected and downloaded >= expected:
phase = "finalizing"
# The cache scan counts every blob of the repo(s), including files a
# previous (or broader) pull left behind that this load never reads, so
# the raw counter can exceed the scoped estimate. Clamp: everything the
# load needs is present, which is what the bar reports.
downloaded = expected
return _progress(
phase,
downloaded_bytes = int(downloaded),
expected_bytes = int(expected) if expected else None,
)
# ── the load itself ──────────────────────────────────────────────────────
def load_pipeline(
self,
repo_id: str,
*,
gguf_filename: Optional[str] = None,
base_repo: Optional[str] = None,
family_override: Optional[str] = None,
hf_token: Optional[str] = None,
memory_mode: Optional[str] = None,
speed_mode: Optional[str] = None,
attention_backend: Optional[str] = None,
transformer_cache: Optional[str] = None,
transformer_cache_threshold: Optional[float] = None,
model_kind: Optional[str] = None,
_load_token: Optional[int] = None,
_base_local_dir: Optional[str] = None,
) -> dict[str, Any]:
import diffusers
import torch
fam = self.validate_load_request(
repo_id,
gguf_filename = gguf_filename,
base_repo = base_repo,
family_override = family_override,
model_kind = model_kind,
)
kind = resolve_video_model_kind(gguf_filename, model_kind)
base = repo_id if kind == "pipeline" else resolve_video_base_repo(fam, base_repo)
with self._lock:
if _load_token is not None and _load_token != self._load_token:
raise RuntimeError("Video load was cancelled or superseded.")
# Signal only a generation from the PREVIOUS model; the token check
# above already bailed a superseded worker before this point.
if self._active_generate_cancel is not None:
self._active_generate_cancel.set()
# Wait for the signalled generation to actually exit before tearing the old
# pipeline down: the denoise loop holds its own pipe reference until the
# next step callback, and freeing/reallocating under it would put two
# models in VRAM at once. generate() holds _generate_lock for its full
# body, so a bare acquire is the exit barrier (never while holding _lock).
with self._generate_lock:
pass
self._teardown_state()
target = resolve_diffusion_device_target()
device = target.device
# Video DiTs are bf16-native; fp16 overflows them, so a resolved fp16
# promotes to float32 (the same rule as the fp16-incompatible image
# families). CPU stays float32.
dtype = target.dtype
if fam.fp16_incompatible and dtype is torch.float16:
dtype = torch.float32
# ── memory plan: family-table resident estimate + frames-aware headroom.
device_memory = snapshot_device_memory(target)
components = fam.bf16_components_gb
mib_per_gb = 1000.0**3 / (1024.0 * 1024.0)
if kind == "pipeline":
model_dense_mib = int(sum(components) * mib_per_gb) if components is not None else None
companion_mib = None
else:
checkpoint_path = self._resolve_checkpoint_path(repo_id, gguf_filename, hf_token)
size_mib = file_size_mib(str(checkpoint_path))
model_dense_mib = None
if kind == "gguf":
transformer_mib = estimate_gguf_resident_mib(size_mib)
else:
transformer_mib = estimate_safetensors_dense_mib(size_mib)
companion_mib = (
int((components[1] + components[2]) * mib_per_gb)
if components is not None
else None
)
# The resident check budgets ALL weights (the image backend's contract):
# the companions stay resident even when only the transformer would fit,
# so budgeting the transformer alone lets auto pick OFFLOAD_NONE and OOM
# while from_pretrained loads the text encoder / VAEs.
model_dense_mib = (
transformer_mib + (companion_mib or 0) if transformer_mib is not None else None
)
runtime_mib = estimate_video_runtime_mib(
width = fam.resolution_presets[0][0],
height = fam.resolution_presets[0][1],
num_frames = fam.default_num_frames,
)
plan = plan_diffusion_memory(
target = target,
device_memory = device_memory,
model_dense_mib = model_dense_mib,
runtime_headroom_mib = runtime_mib,
companion_dense_mib = companion_mib,
requested_mode = normalize_memory_mode(memory_mode),
)
# ── build the pipeline.
pipeline_cls = getattr(diffusers, fam.pipeline_class)
pipe_kwargs: dict[str, Any] = {"torch_dtype": dtype}
if hf_token:
pipe_kwargs["token"] = hf_token
if kind == "pipeline":
# The pre-downloaded snapshot dir keeps from_pretrained off the hub (its
# own snapshot sweep would also pull the repo's packaged root checkpoints
# and duplicate text-encoder shards); hub id when pre-download was skipped.
pipe = pipeline_cls.from_pretrained(_base_local_dir or repo_id, **pipe_kwargs)
else:
transformer_cls = getattr(diffusers, fam.transformer_class)
# checkpoint_path was already resolved (and downloaded) by the memory
# planning branch above for every non-pipeline kind.
sf_kwargs: dict[str, Any] = {
"torch_dtype": dtype,
"config": base,
"subfolder": "transformer",
"token": hf_token,
}
if kind == "gguf":
sf_kwargs["quantization_config"] = diffusers.GGUFQuantizationConfig(
compute_dtype = dtype
)
from .video_ltx2 import is_ltx23_checkpoint, load_ltx23_pipeline
if fam.name == "ltx-2" and is_ltx23_checkpoint(checkpoint_path):
# 2.3 checkpoints need the full assembly: new transformer config
# flags, key renames the stock converter lacks, and the 2.3
# connectors/VAEs/vocoder the 2.0 base repo does not carry.
pipe = load_ltx23_pipeline(
checkpoint_path,
base_repo = base,
torch_dtype = dtype,
is_gguf = kind == "gguf",
hf_token = hf_token,
)
else:
transformer = transformer_cls.from_single_file(str(checkpoint_path), **sf_kwargs)
pipe = pipeline_cls.from_pretrained(
_base_local_dir or base, transformer = transformer, **pipe_kwargs
)
if _load_token is not None and _load_token != self._load_token:
del pipe
clear_gpu_cache()
raise RuntimeError("Video load was cancelled or superseded.")
# ── optimisation layers, in the image backend's order: step cache FIRST
# (compile keys its fullgraph decision off an active cache: FBCache hooks
# graph-break, so compiling fullgraph before installing the cache crashes
# the first cached generation), then attention, the speed profile, and
# placement/offload last.
effective_speed = resolve_speed_mode(speed_mode, is_gguf = kind == "gguf")
backend_flags = snapshot_backend_flags()
cache_engaged = apply_step_cache(
pipe,
mode = normalize_transformer_cache(transformer_cache),
threshold = transformer_cache_threshold,
logger = logger,
)
attention_engaged = apply_attention_backend(
pipe,
select_attention_backend(
target, attention_backend, speed_active = effective_speed != SPEED_OFF
),
logger = logger,
)
speed_optims = apply_speed_optims(
pipe,
target,
is_gguf = kind == "gguf",
family = fam,
speed_mode = effective_speed,
cache_active = cache_engaged is not None,
offload_active = plan.offload_policy != "none",
)
# A cancelled/superseded load must not place weights on the GPU the arbiter
# may already have handed to another backend; recheck right before placement
# (the commit below still does the final locked check).
if _load_token is not None and _load_token != self._load_token:
del pipe
clear_gpu_cache()
raise RuntimeError("Video load was cancelled or superseded.")
offload_policy, vae_tiling = apply_memory_plan(pipe, plan, device = device, logger = logger)
if not vae_tiling:
# Decode of a whole clip is the video memory peak; tiling is near-free
# in quality and keeps the decode bounded, so it is always on.
try:
pipe.vae.enable_tiling()
vae_tiling = True
except Exception as exc: # noqa: BLE001 -- tiling is an optimisation only
logger.warning("video.vae_tiling_failed: %s", exc)
resolved = build_resolved_record(
{
"memory_mode": (
memory_mode,
plan.requested_mode,
f"planned '{plan.offload_policy}' offload from the family size table",
),
"speed_mode": (
speed_mode,
effective_speed,
"GGUF video loads default to the near-lossless compile profile",
),
"attention_backend": (
attention_backend,
attention_engaged or "native",
"cuDNN fused attention on NVIDIA when a speed profile is active",
),
"transformer_cache": (
transformer_cache,
cache_engaged or "off",
"step cache engages on many-step schedules only",
),
}
)
with self._lock:
if _load_token is not None and _load_token != self._load_token:
del pipe
clear_gpu_cache()
raise RuntimeError("Video load was cancelled or superseded.")
self._state = _VideoLoadState(
pipe = pipe,
family = fam,
repo_id = repo_id,
base_repo = base,
device = device,
dtype = str(dtype).replace("torch.", ""),
kind = kind,
gguf_filename = gguf_filename,
offload_policy = offload_policy,
vae_tiling = vae_tiling,
memory_mode = plan.requested_mode,
speed_mode = effective_speed,
# Only the optimisations that actually engaged: apply_speed_optims
# returns every flag with True/False, and iterating the dict raw
# would report disabled ones as active in /video/status.
speed_optims = tuple(k for k, v in (speed_optims or {}).items() if v),
backend_flags = backend_flags,
attention_backend = attention_engaged,
transformer_cache = cache_engaged,
resolved = resolved,
)
logger.info(
"video.loaded: %s (%s, %s, offload=%s, speed=%s)",
repo_id,
fam.name,
kind,
offload_policy,
effective_speed,
)
return self.status()
@staticmethod
def _resolve_checkpoint_path(
repo_id: str, gguf_filename: Optional[str], hf_token: Optional[str]
) -> Path:
"""The local checkpoint file for a gguf/single_file load (downloads if hub)."""
from .diffusion_families import resolve_local_gguf_child
root = Path(repo_id).expanduser()
if root.is_dir():
return resolve_local_gguf_child(root, gguf_filename or "")
if root.is_file():
return root
from utils.hf_xet_fallback import hf_hub_download_with_xet_fallback
return Path(hf_hub_download_with_xet_fallback(repo_id, gguf_filename or "", hf_token))
# ── generation ───────────────────────────────────────────────────────────
@staticmethod
def _reset_step_cache(pipe: Any) -> None:
"""Clear FBCache residuals on the resident DiT(s) before a generation.
diffusers keys the residuals on the long-lived transformer and no pipeline
resets them, so the next clip would compare against the previous request's
state: a shape mismatch when the resolution changed, stale reuse otherwise.
``_reset_stateful_cache`` is the transformer-level entry point in diffusers
0.39 (``reset_stateful_hooks`` lives only on the HookRegistry). Best-effort:
an uncached transformer is a silent no-op."""
for name in ("transformer", "transformer_2"):
module = getattr(pipe, name, None)
reset = getattr(module, "_reset_stateful_cache", None) or getattr(
module, "reset_stateful_hooks", None
)
if callable(reset):
try:
reset()
except Exception: # noqa: BLE001 -- reset is best-effort, never fail a generation
pass
def generate(
self,
*,
prompt: str,
negative_prompt: Optional[str] = None,
width: Optional[int] = None,
height: Optional[int] = None,
num_frames: Optional[int] = None,
fps: Optional[int] = None,
steps: Optional[int] = None,
guidance: Optional[float] = None,
seed: Optional[int] = None,
) -> dict[str, Any]:
import torch
cancel = threading.Event()
with self._generate_lock:
with self._lock:
state = self._state
if state is None:
raise RuntimeError(VIDEO_NOT_LOADED_MSG)
self._active_generate_cancel = cancel
try:
fam = state.family
width, height = snap_video_size(
fam,
width or fam.resolution_presets[0][0],
height or fam.resolution_presets[0][1],
)
frames = snap_num_frames(fam, num_frames or fam.default_num_frames)
out_fps = int(fps or fam.default_fps)
default_steps, default_guidance = default_video_generation_params(
state.gguf_filename, state.repo_id, state.base_repo
)
steps = int(steps or default_steps)
guidance = float(default_guidance if guidance is None else guidance)
generator = torch.Generator(device = state.device)
if seed is None:
seed = int(generator.seed()) % (2**53)
generator = generator.manual_seed(int(seed))
pipe = state.pipe
call_params = inspect.signature(pipe.__call__).parameters
kwargs: dict[str, Any] = {
"prompt": prompt,
"num_inference_steps": steps,
fam.cfg_kwarg: guidance,
"width": width,
"height": height,
"num_frames": frames,
"generator": generator,
}
if negative_prompt and "negative_prompt" in call_params:
kwargs["negative_prompt"] = negative_prompt
# LTX-2 takes frame_rate (it shapes the audio track length); other
# pipelines fix their own rate and fps only matters at export.
if "frame_rate" in call_params:
kwargs["frame_rate"] = float(out_fps)
started = time.monotonic()
self._gen = {
"active": True,
"phase": "denoise",
"step": 0,
"total": steps,
"started": started,
"eta_seconds": None,
"error": None,
}
def _on_step(p, step_index, timestep, callback_kwargs):
if cancel.is_set():
p._interrupt = True
return callback_kwargs
done = step_index + 1
elapsed = time.monotonic() - started
self._gen.update(
step = done,
eta_seconds = (elapsed / max(1, done)) * max(0, steps - done),
)
return callback_kwargs
if "callback_on_step_end" in call_params:
kwargs["callback_on_step_end"] = _on_step
if state.transformer_cache:
self._reset_step_cache(pipe)
with torch.inference_mode():
output = pipe(**kwargs)
if cancel.is_set():
raise RuntimeError(VIDEO_CANCELLED_MSG)
self._gen.update(phase = "export", eta_seconds = None)
video_frames = output.frames[0]
audio = getattr(output, "audio", None)
audio_track = audio[0] if fam.has_audio and audio is not None else None
mp4_bytes = self._encode_mp4(
video_frames, out_fps, audio_track, pipe if fam.has_audio else None
)
duration_s = len(video_frames) / float(out_fps) if out_fps else 0.0
self._gen = {"active": False}
return {
"mp4_bytes": mp4_bytes,
"seed": int(seed),
"repo_id": state.repo_id,
"width": width,
"height": height,
"num_frames": len(video_frames),
"fps": out_fps,
"duration_s": duration_s,
"has_audio": bool(audio_track is not None),
"steps": steps,
"guidance": guidance,
}
except Exception:
self._gen = {"active": False}
raise
finally:
with self._lock:
if self._active_generate_cancel is cancel:
self._active_generate_cancel = None
@staticmethod
def _encode_mp4(video_frames, fps: int, audio, pipe) -> bytes:
"""Encode frames (+ optional audio) to H.264 MP4 bytes via diffusers' PyAV
exporter. A temp file bridges the exporter's path-based API; the bytes are
what the gallery persists."""
from diffusers.utils.export_utils import encode_video
tmp = tempfile.NamedTemporaryFile(suffix = ".mp4", delete = False)
tmp.close()
try:
encode_kwargs: dict[str, Any] = {}
if audio is not None and pipe is not None:
encode_kwargs["audio"] = audio
sample_rate = getattr(
getattr(getattr(pipe, "vocoder", None), "config", None),
"output_sampling_rate",
None,
)
if sample_rate:
encode_kwargs["audio_sample_rate"] = int(sample_rate)
encode_video(video_frames, fps, tmp.name, **encode_kwargs)
return Path(tmp.name).read_bytes()
finally:
try:
os.unlink(tmp.name)
except OSError:
pass
def generate_progress(self) -> dict[str, Any]:
gen = dict(self._gen)
gen.setdefault("active", False)
return gen
def cancel_generate(self) -> bool:
"""Signal the in-flight generation to stop at its next step callback."""
with self._lock:
cancel = self._active_generate_cancel
if cancel is None:
return False
cancel.set()
return True
# ── teardown + status ────────────────────────────────────────────────────
def _teardown_state(self) -> None:
state = None
with self._lock:
state, self._state = self._state, None
if state is not None:
restore_backend_flags(state.backend_flags)
# A GGUF video load may have installed the process-wide compiled GGUF
# dequantizer; restore the stock kernels so a later load that asked for
# speed_mode=off gets the bit-identical path (mirrors the image unload).
from . import diffusion_gguf_compile
diffusion_gguf_compile.uninstall_all()
del state
clear_gpu_cache()
def unload(self) -> dict[str, Any]:
with self._lock:
self._load_token += 1
self._cancel_event.set()
self._loading = None
if self._active_generate_cancel is not None:
self._active_generate_cancel.set()
self._teardown_state()
logger.info("video.unloaded")
return self.status()
def status(self) -> dict[str, Any]:
state = self._state
if state is None:
return {
"loaded": False,
"repo_id": None,
"family": None,
"base_repo": None,
"device": None,
"dtype": None,
"model_kind": None,
"offload_policy": None,
"vae_tiling": False,
"memory_mode": None,
"speed_mode": None,
"speed_optims": [],
"attention_backend": None,
"transformer_cache": None,
"has_audio": False,
"defaults": None,
"resolved": None,
}
fam = state.family
default_steps, default_guidance = default_video_generation_params(
state.gguf_filename, state.repo_id, state.base_repo
)
return {
"loaded": True,
"repo_id": state.repo_id,
"family": fam.name,
"base_repo": state.base_repo,
"device": state.device,
"dtype": state.dtype,
"model_kind": state.kind,
"offload_policy": state.offload_policy,
"vae_tiling": state.vae_tiling,
"memory_mode": state.memory_mode,
"speed_mode": state.speed_mode,
"speed_optims": list(state.speed_optims),
"attention_backend": state.attention_backend,
"transformer_cache": state.transformer_cache,
"has_audio": fam.has_audio,
"defaults": {
"steps": default_steps,
"guidance": default_guidance,
"num_frames": fam.default_num_frames,
"fps": fam.default_fps,
"frame_step": fam.frame_step,
"resolution_multiple": fam.resolution_multiple,
"resolution_presets": [list(p) for p in fam.resolution_presets],
},
"resolved": state.resolved,
}
_backend: Optional[VideoBackend] = None
_backend_lock = threading.Lock()
def get_video_backend() -> VideoBackend:
global _backend
with _backend_lock:
if _backend is None:
_backend = VideoBackend()
return _backend