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hao-ai-lab-FastVideo/fastvideo/v1/entrypoints/video_generator.py

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11 KiB
Python

# SPDX-License-Identifier: Apache-2.0
"""
VideoGenerator module for FastVideo.
This module provides a consolidated interface for generating videos using
diffusion models.
"""
import gc
import math
import os
import time
from typing import Any, Dict, List, Optional, Union
import imageio
import numpy as np
import torch
import torchvision
from einops import rearrange
from fastvideo.v1.configs.sample import SamplingParam
from fastvideo.v1.fastvideo_args import FastVideoArgs
from fastvideo.v1.logger import init_logger
from fastvideo.v1.pipelines import ForwardBatch
from fastvideo.v1.utils import align_to, shallow_asdict
from fastvideo.v1.worker.executor import Executor
logger = init_logger(__name__)
class VideoGenerator:
"""
A unified class for generating videos using diffusion models.
This class provides a simple interface for video generation with rich
customization options, similar to popular frameworks like HF Diffusers.
"""
def __init__(self, fastvideo_args: FastVideoArgs,
executor_class: type[Executor], log_stats: bool):
"""
Initialize the video generator.
Args:
fastvideo_args: The inference arguments
executor_class: The executor class to use for inference
"""
self.fastvideo_args = fastvideo_args
self.executor = executor_class(fastvideo_args)
@classmethod
def from_pretrained(cls,
model_path: str,
device: Optional[str] = None,
torch_dtype: Optional[torch.dtype] = None,
**kwargs) -> "VideoGenerator":
"""
Create a video generator from a pretrained model.
Args:
model_path: Path or identifier for the pretrained model
device: Device to load the model on (e.g., "cuda", "cuda:0", "cpu")
torch_dtype: Data type for model weights (e.g., torch.float16)
pipeline_config: Pipeline config to use for inference
**kwargs: Additional arguments to customize model loading, set any FastVideoArgs or PipelineConfig attributes here.
Returns:
The created video generator
Priority level: Default pipeline config < User's pipeline config < User's kwargs
"""
# If users also provide some kwargs, it will override the FastVideoArgs and PipelineConfig.
kwargs['model_path'] = model_path
fastvideo_args = FastVideoArgs.from_kwargs(kwargs)
return cls.from_fastvideo_args(fastvideo_args)
@classmethod
def from_fastvideo_args(cls,
fastvideo_args: FastVideoArgs) -> "VideoGenerator":
"""
Create a video generator with the specified arguments.
Args:
fastvideo_args: The inference arguments
Returns:
The created video generator
"""
# Initialize distributed environment if needed
# initialize_distributed_and_parallelism(fastvideo_args)
executor_class = Executor.get_class(fastvideo_args)
return cls(
fastvideo_args=fastvideo_args,
executor_class=executor_class,
log_stats=False, # TODO: implement
)
def generate_video(
self,
prompt: str,
sampling_param: Optional[SamplingParam] = None,
**kwargs,
) -> Union[Dict[str, Any], List[np.ndarray]]:
"""
Generate a video based on the given prompt.
Args:
prompt: The prompt to use for generation
negative_prompt: The negative prompt to use (overrides the one in fastvideo_args)
output_path: Path to save the video (overrides the one in fastvideo_args)
save_video: Whether to save the video to disk
return_frames: Whether to return the raw frames
num_inference_steps: Number of denoising steps (overrides fastvideo_args)
guidance_scale: Classifier-free guidance scale (overrides fastvideo_args)
num_frames: Number of frames to generate (overrides fastvideo_args)
height: Height of generated video (overrides fastvideo_args)
width: Width of generated video (overrides fastvideo_args)
fps: Frames per second for saved video (overrides fastvideo_args)
seed: Random seed for generation (overrides fastvideo_args)
callback: Callback function called after each step
callback_steps: Number of steps between each callback
Returns:
Either the output dictionary or the list of frames depending on return_frames
"""
# Create a copy of inference args to avoid modifying the original
fastvideo_args = self.fastvideo_args
pipeline_config = fastvideo_args.pipeline_config
# Validate inputs
if not isinstance(prompt, str):
raise TypeError(
f"`prompt` must be a string, but got {type(prompt)}")
prompt = prompt.strip()
if sampling_param is None:
sampling_param = SamplingParam.from_pretrained(
fastvideo_args.model_path)
kwargs["prompt"] = prompt
sampling_param.update(kwargs)
# Process negative prompt
if sampling_param.negative_prompt is not None:
sampling_param.negative_prompt = sampling_param.negative_prompt.strip(
)
# Validate dimensions
if (sampling_param.height <= 0 or sampling_param.width <= 0
or sampling_param.num_frames <= 0):
raise ValueError(
f"Height, width, and num_frames must be positive integers, got "
f"height={sampling_param.height}, width={sampling_param.width}, "
f"num_frames={sampling_param.num_frames}")
temporal_scale_factor = pipeline_config.vae_config.arch_config.temporal_compression_ratio
num_frames = sampling_param.num_frames
num_gpus = fastvideo_args.num_gpus
use_temporal_scaling_frames = pipeline_config.vae_config.use_temporal_scaling_frames
# Adjust number of frames based on number of GPUs
if use_temporal_scaling_frames:
orig_latent_num_frames = (num_frames -
1) // temporal_scale_factor + 1
else: # stepvideo only
orig_latent_num_frames = sampling_param.num_frames // 17 * 3
if orig_latent_num_frames % fastvideo_args.num_gpus != 0:
# Adjust latent frames to be divisible by number of GPUs
if sampling_param.num_frames_round_down:
# Ensure we have at least 1 batch per GPU
new_latent_num_frames = max(
1, (orig_latent_num_frames // num_gpus)) * num_gpus
else:
new_latent_num_frames = math.ceil(
orig_latent_num_frames / num_gpus) * num_gpus
if use_temporal_scaling_frames:
# Convert back to number of frames, ensuring num_frames-1 is a multiple of temporal_scale_factor
new_num_frames = (new_latent_num_frames -
1) * temporal_scale_factor + 1
else: # stepvideo only
# Find the least common multiple of 3 and num_gpus
divisor = math.lcm(3, num_gpus)
# Round up to the nearest multiple of this LCM
new_latent_num_frames = (
(new_latent_num_frames + divisor - 1) // divisor) * divisor
# Convert back to actual frames using the StepVideo formula
new_num_frames = new_latent_num_frames // 3 * 17
logger.info(
"Adjusting number of frames from %s to %s based on number of GPUs (%s)",
sampling_param.num_frames, new_num_frames,
fastvideo_args.num_gpus)
sampling_param.num_frames = new_num_frames
# Calculate sizes
target_height = align_to(sampling_param.height, 16)
target_width = align_to(sampling_param.width, 16)
# Calculate latent sizes
latents_size = [(sampling_param.num_frames - 1) // 4 + 1,
sampling_param.height // 8, sampling_param.width // 8]
n_tokens = latents_size[0] * latents_size[1] * latents_size[2]
# Log parameters
debug_str = f"""
height: {target_height}
width: {target_width}
video_length: {sampling_param.num_frames}
prompt: {prompt}
neg_prompt: {sampling_param.negative_prompt}
seed: {sampling_param.seed}
infer_steps: {sampling_param.num_inference_steps}
num_videos_per_prompt: {sampling_param.num_videos_per_prompt}
guidance_scale: {sampling_param.guidance_scale}
n_tokens: {n_tokens}
flow_shift: {fastvideo_args.pipeline_config.flow_shift}
embedded_guidance_scale: {fastvideo_args.pipeline_config.embedded_cfg_scale}
save_video: {sampling_param.save_video}
output_path: {sampling_param.output_path}
""" # type: ignore[attr-defined]
logger.info(debug_str)
# Prepare batch
batch = ForwardBatch(
**shallow_asdict(sampling_param),
eta=0.0,
n_tokens=n_tokens,
VSA_sparsity=fastvideo_args.VSA_sparsity,
extra={},
)
# Run inference
start_time = time.perf_counter()
output_batch = self.executor.execute_forward(batch, fastvideo_args)
samples = output_batch
gen_time = time.perf_counter() - start_time
logger.info("Generated successfully in %.2f seconds", gen_time)
# Process outputs
videos = rearrange(samples, "b c t h w -> t b c h w")
frames = []
for x in videos:
x = torchvision.utils.make_grid(x, nrow=6)
x = x.transpose(0, 1).transpose(1, 2).squeeze(-1)
frames.append((x * 255).numpy().astype(np.uint8))
# Save video if requested
if batch.save_video:
output_path = batch.output_path
if output_path:
os.makedirs(output_path, exist_ok=True)
video_path = os.path.join(output_path, f"{prompt[:100]}.mp4")
imageio.mimsave(video_path, frames, fps=batch.fps, format="mp4")
logger.info("Saved video to %s", video_path)
else:
logger.warning("No output path provided, video not saved")
if batch.return_frames:
return frames
else:
return {
"samples": samples,
"prompts": prompt,
"size": (target_height, target_width, batch.num_frames),
"generation_time": gen_time
}
def set_lora_adapter(self, lora_nickname: str, lora_path: str) -> None:
self.executor.set_lora_adapter(lora_nickname, lora_path)
def shutdown(self):
"""
Shutdown the video generator.
"""
self.executor.shutdown()
del self.executor
gc.collect()
torch.cuda.empty_cache()