general.py

# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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import argparse
import os

import numpy as np
import torch
from huggingface_hub import snapshot_download
from megatron.core.tensor_parallel.random import model_parallel_cuda_manual_seed
from nemo import lightning as nl
from nemo.lightning.megatron_parallel import MegatronParallel

MegatronParallel.init_ddp = lambda self: None
from nemo.collections.diffusion.mcore_parallel_utils import Utils
from nemo.collections.diffusion.sampler.conditioner import VideoConditioner
from nemo.collections.diffusion.sampler.conditioner_configs import (
    FPSConfig,
    ImageSizeConfig,
    NumFramesConfig,
    PaddingMaskConfig,
    TextConfig,
)
from nemo.collections.diffusion.sampler.cosmos.cosmos_diffusion_pipeline import CosmosDiffusionPipeline
from transformers import T5EncoderModel, T5TokenizerFast

from cosmos1.models.diffusion.nemo.inference.inference_utils import process_prompt, save_video
from cosmos1.utils import log

EXAMPLE_PROMPT = (
    "The teal robot is cooking food in a kitchen. Steam rises from a simmering pot "
    "as the robot chops vegetables on a worn wooden cutting board. Copper pans hang "
    "from an overhead rack, catching glints of afternoon light, while a well-loved "
    "cast iron skillet sits on the stovetop next to scattered measuring spoons and "
    "a half-empty bottle of olive oil."
)


def parse_args():
    parser = argparse.ArgumentParser(description="Video foundation model inference")
    parser.add_argument(
        "--model",
        type=str,
        default="Cosmos-1.0-Diffusion-7B-Text2World",
        choices=["Cosmos-1.0-Diffusion-7B-Text2World", "Cosmos-1.0-Diffusion-14B-Text2World"],
    )
    parser.add_argument(
        "--prompt",
        type=str,
        default=EXAMPLE_PROMPT,
        help="Prompt which the sampled video condition on",
    )
    # We turn on negative prompt by default. set to "" to turn it off.
    parser.add_argument(
        "--negative_prompt",
        type=str,
        default=(
            "The video captures a series of frames showing ugly scenes, static with no motion, motion blur, "
            "over-saturation, shaky footage, low resolution, grainy texture, pixelated images, poorly lit areas, "
            "underexposed and overexposed scenes, poor color balance, washed out colors, choppy sequences, "
            "jerky movements, low frame rate, artifacting, color banding, unnatural transitions, outdated special effects, "
            "fake elements, unconvincing visuals, poorly edited content, jump cuts, visual noise, and flickering. "
            "Overall, the video is of poor quality."
        ),
        help="Negative prompt which the sampled video condition on",
    )
    parser.add_argument("--subject_name", type=str, default="", help="Name of fine-tuned subject")
    parser.add_argument("--guidance", type=float, default=7, help="Classifier-free guidance scale")
    parser.add_argument("--sampler", type=str, default="RES", help="Currently only supports RES sampler.")
    parser.add_argument("--video_save_path", type=str, default="outputs", help="Path to save the video")
    parser.add_argument("--fps", type=int, default=24, help="FPS of the sampled video")
    parser.add_argument("--height", type=int, default=704, help="Height of image to sample")
    parser.add_argument("--width", type=int, default=1280, help="Width of image to sample")
    parser.add_argument("--seed", type=int, default=1, help="Random seed")
    parser.add_argument("--num_devices", type=int, default=1, help="Number of devices for inference")
    parser.add_argument("--cp_size", type=int, default=1, help="Number of cp ranks for multi-gpu inference.")
    parser.add_argument("--num_steps", type=float, default=35, help="Number of diffusion sampling steps")
    parser.add_argument("--num_video_frames", type=int, default=121, help="Number of video frames to sample")
    parser.add_argument("--tokenizer_dir", type=str, default="", help="Directory for video tokenizer")
    parser.add_argument("--cosmos_assets_dir", type=str, default="", help="Directory containing cosmos assets")
    parser.add_argument("--prompt_upsampler_dir", type=str, default="", help="Prompt upsampler weights directory")
    parser.add_argument("--guardrail_dir", type=str, default="", help="Guardrails weights directory")
    parser.add_argument("--nemo_checkpoint", type=str, default="", help="Video diffusion model nemo weights")
    parser.add_argument("--t5_cache_dir", type=str, default=None, help="Path to T5 model")
    parser.add_argument(
        "--enable_prompt_upsampler", action="store_true", help="Whether to use prompt upsampling before generation"
    )

    args = parser.parse_args()
    return args


def print_rank_0(string: str):
    rank = torch.distributed.get_rank()
    if rank == 0:
        log.info(string)


@torch.no_grad()
def encode_for_batch(tokenizer: T5TokenizerFast, encoder: T5EncoderModel, prompts: list[str], max_length: int = 512):
    """
    Encode a batch of text prompts to a batch of T5 embeddings.
    Parameters:
        tokenizer: T5 embedding tokenizer.
        encoder: T5 embedding text encoder.
        prompts: A batch of text prompts.
        max_length: Sequence length of text embedding (defaults to 512).
    """

    batch_encoding = tokenizer.batch_encode_plus(
        prompts,
        return_tensors="pt",
        truncation=True,
        padding="max_length",
        max_length=max_length,
        return_length=True,
        return_offsets_mapping=False,
    )

    # We expect all the processing is done on GPU.
    input_ids = batch_encoding.input_ids.cuda()
    attn_mask = batch_encoding.attention_mask.cuda()

    outputs = encoder(input_ids=input_ids, attention_mask=attn_mask)
    encoded_text = outputs.last_hidden_state

    lengths = attn_mask.sum(dim=1).cpu()
    for batch_id in range(encoded_text.shape[0]):
        encoded_text[batch_id][lengths[batch_id] :] = 0

    return encoded_text


def init_video_tokenizer(args):
    """
    Initializes video tokenizer based on specified video tokenizer config / path.
    """
    from nemo.collections.diffusion.models.model import DiT7BConfig, DiT14BConfig

    vae_path = os.path.join(args.cosmos_assets_dir, args.tokenizer_dir)
    if "7b" in args.nemo_checkpoint.lower():
        dit_config = DiT7BConfig(vae_path=vae_path)
    if "14b" in args.nemo_checkpoint.lower():
        dit_config = DiT14BConfig(vae_path=vae_path)
    vae = dit_config.configure_vae()
    return vae


def check_prompt(args):
    prompt = args.prompt
    subject_string = None
    if args.subject_name:
        subject_string = f"A video of sks {args.subject_name}"

    prompt = process_prompt(
        prompt=prompt,
        checkpoint_dir=args.cosmos_assets_dir,
        prompt_upsampler_dir=args.prompt_upsampler_dir,
        guardrails_dir=args.guardrail_dir,
        enable_prompt_upsampler=args.enable_prompt_upsampler,
    )

    if subject_string:
        prompt = f"{subject_string}. {prompt}"
    return prompt


def prepare_data_batch(args, vae, t5_embeding_max_length=512):
    tokenizer = T5TokenizerFast.from_pretrained("google-t5/t5-11b", cache_dir=args.t5_cache_dir)
    text_encoder = T5EncoderModel.from_pretrained("google-t5/t5-11b", cache_dir=args.t5_cache_dir)
    text_encoder.to("cuda")
    text_encoder.eval()

    # Encode text to T5 embedding
    out = encode_for_batch(tokenizer, text_encoder, [args.prompt])[0]
    encoded_text = torch.tensor(out, dtype=torch.bfloat16)

    # Padding T5 embedding to t5_embeding_max_length
    L, C = encoded_text.shape
    t5_embed = torch.zeros(1, t5_embeding_max_length, C, dtype=torch.bfloat16)
    t5_embed[0, :L] = encoded_text

    if args.negative_prompt:
        out = encode_for_batch(tokenizer, text_encoder, [args.negative_prompt])[0]

        encoded_text = torch.tensor(out, dtype=torch.bfloat16)
        # Padding T5 embedding to t5_embeding_max_length
        L, C = encoded_text.shape
        neg_t5_embed = torch.zeros(1, t5_embeding_max_length, C, dtype=torch.bfloat16)
        neg_t5_embed[0, :L] = encoded_text
    else:
        neg_t5_embed = None

    # Prepare data sample
    t, h, w = args.num_video_frames, args.height, args.width
    state_shape = [
        vae.channel,
        vae.get_latent_num_frames(t),
        h // vae.spatial_compression_factor,
        w // vae.spatial_compression_factor,
    ]

    data_batch = {
        "video": torch.zeros((1, 3, t, h, w), dtype=torch.uint8).cuda(),
        "t5_text_embeddings": t5_embed,
        "t5_text_mask": torch.ones(1, t5_embeding_max_length, dtype=torch.bfloat16).cuda(),
        # other conditions
        "image_size": torch.tensor(
            [[args.height, args.width, args.height, args.width]] * 1, dtype=torch.bfloat16
        ).cuda(),
        "fps": torch.tensor([args.fps] * 1, dtype=torch.bfloat16).cuda(),
        "num_frames": torch.tensor([args.num_video_frames] * 1, dtype=torch.bfloat16).cuda(),
        "padding_mask": torch.zeros((1, 1, args.height, args.width), dtype=torch.bfloat16).cuda(),
    }
    if args.negative_prompt:
        data_batch["neg_t5_text_embeddings"] = neg_t5_embed
        data_batch["neg_t5_text_mask"] = torch.ones(1, t5_embeding_max_length, dtype=torch.bfloat16)

    return data_batch, state_shape


def setup_diffusion_pipeline(args):
    """
    Initialize DiT model, parallel strategy, and diffusion pipeline for inference.
    """
    # Initialize DiT model
    from nemo.collections.diffusion.models.model import DiT7BConfig, DiT14BConfig, DiTModel

    if "7b" in args.nemo_checkpoint.lower():
        dit_config = DiT7BConfig()
    if "14b" in args.nemo_checkpoint.lower():
        dit_config = DiT14BConfig()

    dit_model = DiTModel(dit_config)

    # Initialize model parallel strategy. Here, we only use context parallel.
    strategy = nl.MegatronStrategy(
        tensor_model_parallel_size=1,
        pipeline_model_parallel_size=1,
        context_parallel_size=args.cp_size,
        pipeline_dtype=torch.bfloat16,
    )

    # Initialize ptl trainer
    trainer = nl.Trainer(
        devices=args.num_devices,  # you can change the numebr of devices to suit your setup
        max_steps=1,
        accelerator="gpu",
        strategy=strategy,
        plugins=nl.MegatronMixedPrecision(precision="bf16-mixed"),
    )

    # Convert trainer to fabric for inference
    fabric = trainer.to_fabric()
    fabric.strategy.checkpoint_io.save_ckpt_format = "zarr"
    fabric.strategy.checkpoint_io.validate_access_integrity = False
    model = fabric.load_model(args.nemo_checkpoint, dit_model).to(device="cuda", dtype=torch.bfloat16)

    # Set up diffusion pipeline
    conditioner = VideoConditioner(
        text=TextConfig(),
        fps=FPSConfig(),
        num_frames=NumFramesConfig(),
        image_size=ImageSizeConfig(),
        padding_mask=PaddingMaskConfig(),
    )
    diffusion_pipeline = CosmosDiffusionPipeline(
        net=model.module, conditioner=conditioner, sampler_type=args.sampler, seed=args.seed
    )

    return diffusion_pipeline


def run_diffusion_inference(args, data_batch, state_shape, vae, diffusion_pipeline):
    # prepare data
    data_batch = {k: v.cuda() if torch.is_tensor(v) else v for k, v in data_batch.items()}
    data_batch["inference_fwd"] = True
    sample = diffusion_pipeline.generate_samples_from_batch(
        data_batch,
        guidance=args.guidance,
        state_shape=state_shape,
        num_steps=args.num_steps,
        is_negative_prompt=True if "neg_t5_text_embeddings" in data_batch else False,
    )

    rank = torch.distributed.get_rank()
    if rank == 0:
        # Post-processing and save video
        sigma_data = 0.5
        grid = (1.0 + vae.decode(sample / sigma_data)).clamp(0, 2) / 2
        grid = (grid[0].permute(1, 2, 3, 0) * 255).to(torch.uint8).cpu().numpy().astype(np.uint8)
        save_video(
            grid=grid,
            fps=args.fps,
            H=args.height,
            W=args.width,
            video_save_quality=5,
            video_save_path=args.video_save_path,
            checkpoint_dir=args.cosmos_assets_dir,
            guardrails_dir=args.guardrail_dir,
        )
        print_rank_0(f"saved video to {args.video_save_path}!")


def main(args):
    if args.guardrail_dir == "":
        args.guardrail_dir = snapshot_download("nvidia/Cosmos-1.0-Guardrail")
    if args.tokenizer_dir == "":
        args.tokenizer_dir = snapshot_download("nvidia/Cosmos-1.0-Tokenizer-CV8x8x8")
    if args.prompt_upsampler_dir == "" and args.enable_prompt_upsampler:
        args.prompt_upsampler_dir = snapshot_download("nvidia/Cosmos-1.0-Prompt-Upsampler-12B-Text2World")
    if args.nemo_checkpoint == "":
        args.nemo_checkpoint = snapshot_download(f"nvidia/{args.model}", allow_patterns=["nemo/*"])
        args.nemo_checkpoint = os.path.join(args.nemo_checkpoint, "nemo")

    # Initialize megatron model parallel environment
    Utils.initialize_distributed(1, 1, context_parallel_size=args.cp_size)
    model_parallel_cuda_manual_seed(args.seed)

    args.prompt = check_prompt(args)

    # Load video tokenizer
    print_rank_0("initializing video tokenizer...")
    vae = init_video_tokenizer(args)

    # Prepare data batch
    print_rank_0("preparing data batch...")
    data_batch, state_shape = prepare_data_batch(args, vae)

    # Setup model / diffusion pipeline
    print_rank_0("setting up diffusion pipeline...")
    diffusion_pipeline = setup_diffusion_pipeline(args)

    # Generate video from prompt
    print_rank_0("generating video...")
    run_diffusion_inference(args, data_batch, state_shape, vae, diffusion_pipeline)


if __name__ == "__main__":
    args = parse_args()
    main(args)