SolitaryThinker
825c6365e0
A bundle's training variant (header-declared `variant`, filename token as
fallback) now selects its sampling preset: distilled -> ltx2_distilled
(8 steps, cfg 1.0, distilled sigmas engage at <=8 steps), sft/base ->
ltx2_base. The bundle table also pins the pipeline class, so
VideoGenerator.from_pretrained(<bundle>) resolves without an override.
Adds basic_ltx2_5{,_distilled}.py examples (--model-path takes the FILE,
--gemma-root declares the paired encoder root), a README section, and CPU
tests for variant/preset resolution, table integrity, and the examples.
104 lines
4.5 KiB
Python
104 lines
4.5 KiB
Python
# SPDX-License-Identifier: Apache-2.0
|
|
"""LTX-2.5 (sft/base) text-to-video from a single-file bundle.
|
|
|
|
Loads LTX-2.5 from a single-file bundle: ONE ``.safetensors`` file carrying
|
|
every component (transformer, video VAE, audio VAE, vocoder, text
|
|
projection), so ``--model-path`` takes the bundle FILE, not a repo
|
|
directory. (The split-pack Hugging Face release loads through the standard
|
|
repo path instead.)
|
|
|
|
The Gemma text encoder is NOT in the bundle: pass its root directory with
|
|
``--gemma-root`` (or set ``FASTVIDEO_LTX_ENCODER_ROOT``). Use the encoder
|
|
root shipped WITH this transformer variant -- the published roots share
|
|
weights but differ in prompt templating, so a mismatched root silently
|
|
changes prompting.
|
|
|
|
A non-distilled bundle resolves to the standard ``ltx2_base`` preset
|
|
(40 steps, CFG 3.0 with STG); run without sampling flags to use it as-is.
|
|
For the 8-step distilled recipe, see ``basic_ltx2_5_distilled.py``.
|
|
|
|
Audio: the bundle carries an audio VAE + vocoder, so generated videos get
|
|
an audio track. A bundle that declares no audio decoder skips audio
|
|
decoding and still produces video.
|
|
|
|
Decoder caveat: bundles that declare a *diffusion* VAE decoder
|
|
(``CausalDiffusionVAE``) are not implemented yet -- loading such a bundle
|
|
currently fails at VAE build time with an unsupported-architecture error
|
|
(no classic-decoder fallback is wired). Bundles with the classic
|
|
``CausalVideoAutoencoder`` decode end to end.
|
|
"""
|
|
import argparse
|
|
import os
|
|
|
|
from fastvideo import VideoGenerator
|
|
|
|
PROMPT = ("A warm sunny backyard. The camera starts in a tight cinematic close-up "
|
|
"of a woman and a man in their 30s, facing each other with serious "
|
|
"expressions. The woman, emotional and dramatic, says softly, \"That's "
|
|
"it... Dad's lost it. And we've lost Dad.\" The man exhales, slightly "
|
|
"annoyed: \"Stop being so dramatic, Jess.\" A beat. He glances aside, "
|
|
"then mutters defensively, \"He's just having fun.\" The camera slowly "
|
|
"pans right, revealing the grandfather in the garden wearing enormous "
|
|
"butterfly wings, waving his arms in the air like he's trying to take "
|
|
"off. He shouts, \"Wheeeew!\" as he flaps his wings with full commitment. "
|
|
"The woman covers her face, on the verge of tears. The tone is deadpan, "
|
|
"absurd, and quietly tragic.")
|
|
|
|
# Sampling flags default to None: unset flags are NOT passed to
|
|
# `generate_video`, so the bundle's preset supplies them via
|
|
# `SamplingParam.from_pretrained` (ltx2_base: 40 steps, cfg 3.0, 512x768,
|
|
# 121 frames).
|
|
_SAMPLING_FLAGS = ("height", "width", "num_frames", "num_inference_steps", "guidance_scale", "seed")
|
|
|
|
|
|
def parse_args(argv: list[str] | None = None) -> argparse.Namespace:
|
|
parser = argparse.ArgumentParser(description="LTX-2.5 (sft/base) inference from a single-file bundle.")
|
|
parser.add_argument(
|
|
"--model-path",
|
|
required=True,
|
|
help="Path to the LTX-2.5 bundle (.safetensors FILE).",
|
|
)
|
|
parser.add_argument(
|
|
"--gemma-root",
|
|
default=None,
|
|
help="Gemma text-encoder root directory. Must be the root paired with "
|
|
"this transformer variant; the roots differ in prompt templating.",
|
|
)
|
|
parser.add_argument("--prompt", default=PROMPT)
|
|
parser.add_argument("--output-path", default="outputs_video/ltx2_5/output_ltx2_5_t2v.mp4")
|
|
parser.add_argument("--num-gpus", type=int, default=1)
|
|
parser.add_argument("--height", type=int, default=None)
|
|
parser.add_argument("--width", type=int, default=None)
|
|
parser.add_argument("--num-frames", type=int, default=None)
|
|
parser.add_argument("--num-inference-steps", type=int, default=None)
|
|
parser.add_argument("--guidance-scale", type=float, default=None)
|
|
parser.add_argument("--seed", type=int, default=None)
|
|
return parser.parse_args(argv)
|
|
|
|
|
|
def sampling_overrides(args: argparse.Namespace) -> dict:
|
|
"""Only sampling flags the user actually passed; the preset supplies the rest."""
|
|
return {name: getattr(args, name) for name in _SAMPLING_FLAGS if getattr(args, name) is not None}
|
|
|
|
|
|
def main(argv: list[str] | None = None) -> None:
|
|
args = parse_args(argv)
|
|
if args.gemma_root:
|
|
os.environ["FASTVIDEO_LTX_ENCODER_ROOT"] = args.gemma_root
|
|
|
|
generator = VideoGenerator.from_pretrained(
|
|
args.model_path,
|
|
num_gpus=args.num_gpus,
|
|
)
|
|
generator.generate_video(
|
|
prompt=args.prompt,
|
|
output_path=args.output_path,
|
|
save_video=True,
|
|
**sampling_overrides(args),
|
|
)
|
|
generator.shutdown()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|