app.py

import sys
from pathlib import Path

# Add packages to Python path
current_dir = Path(__file__).parent
sys.path.insert(0, str(current_dir / "packages" / "ltx-pipelines" / "src"))
sys.path.insert(0, str(current_dir / "packages" / "ltx-core" / "src"))
import numpy as np
import random
import spaces
import gradio as gr
from typing import Optional
from huggingface_hub import hf_hub_download
from ltx_pipelines.ti2vid_two_stages import TI2VidTwoStagesPipeline
from ltx_core.tiling import TilingConfig
from ltx_pipelines.constants import (
    DEFAULT_SEED,
    DEFAULT_HEIGHT,
    DEFAULT_WIDTH,
    DEFAULT_NUM_FRAMES,
    DEFAULT_FRAME_RATE,
    DEFAULT_NUM_INFERENCE_STEPS,
    DEFAULT_CFG_GUIDANCE_SCALE,
    DEFAULT_LORA_STRENGTH,
)

MAX_SEED = np.iinfo(np.int32).max
# Custom negative prompt
DEFAULT_NEGATIVE_PROMPT = "shaky, glitchy, low quality, worst quality, deformed, distorted, disfigured, motion smear, motion artifacts, fused fingers, bad anatomy, weird hand, ugly, transition, static"

# Default prompt from docstring example
DEFAULT_PROMPT = "An astronaut hatches from a fragile egg on the surface of the Moon, the shell cracking and peeling apart in gentle low-gravity motion. Fine lunar dust lifts and drifts outward with each movement, floating in slow arcs before settling back onto the ground. The astronaut pushes free in a deliberate, weightless motion, small fragments of the egg tumbling and spinning through the air. In the background, the deep darkness of space subtly shifts as stars glide with the camera's movement, emphasizing vast depth and scale. The camera performs a smooth, cinematic slow push-in, with natural parallax between the foreground dust, the astronaut, and the distant starfield. Ultra-realistic detail, physically accurate low-gravity motion, cinematic lighting, and a breath-taking, movie-like shot."

# HuggingFace Hub defaults
DEFAULT_REPO_ID = "Lightricks/LTX-2"
DEFAULT_GEMMA_REPO_ID = "google/gemma-3-12b-it-qat-q4_0-unquantized"
DEFAULT_CHECKPOINT_FILENAME = "ltx-2-19b-dev-fp8.safetensors"
DEFAULT_DISTILLED_LORA_FILENAME = "ltx-2-19b-distilled-lora-384.safetensors"
DEFAULT_SPATIAL_UPSAMPLER_FILENAME = "ltx-2-spatial-upscaler-x2-1.0.safetensors"

def get_hub_or_local_checkpoint(repo_id: Optional[str] = None, filename: Optional[str] = None):
    """Download from HuggingFace Hub or use local checkpoint."""
    if repo_id is None and filename is None:
        raise ValueError("Please supply at least one of `repo_id` or `filename`")

    if repo_id is not None:
        if filename is None:
            raise ValueError("If repo_id is specified, filename must also be specified.")
        print(f"Downloading {filename} from {repo_id}...")
        ckpt_path = hf_hub_download(repo_id=repo_id, filename=filename)
        print(f"Downloaded to {ckpt_path}")
    else:
        ckpt_path = filename

    return ckpt_path


# Initialize pipeline at startup
print("=" * 80)
print("Loading LTX-2 2-stage pipeline...")
print("=" * 80)

checkpoint_path = get_hub_or_local_checkpoint(DEFAULT_REPO_ID, DEFAULT_CHECKPOINT_FILENAME)
distilled_lora_path = get_hub_or_local_checkpoint(DEFAULT_REPO_ID, DEFAULT_DISTILLED_LORA_FILENAME)
spatial_upsampler_path = get_hub_or_local_checkpoint(DEFAULT_REPO_ID, DEFAULT_SPATIAL_UPSAMPLER_FILENAME)

print(f"Initializing pipeline with:")
print(f"  checkpoint_path={checkpoint_path}")
print(f"  distilled_lora_path={distilled_lora_path}")
print(f"  spatial_upsampler_path={spatial_upsampler_path}")
print(f"  gemma_root={DEFAULT_GEMMA_REPO_ID}")

pipeline = TI2VidTwoStagesPipeline(
    checkpoint_path=checkpoint_path,
    distilled_lora_path=distilled_lora_path,
    distilled_lora_strength=DEFAULT_LORA_STRENGTH,
    spatial_upsampler_path=spatial_upsampler_path,
    gemma_root=DEFAULT_GEMMA_REPO_ID,
    loras=[],
    fp8transformer=False,
    local_files_only=False
)

@spaces.GPU(duration=300)
def generate_video(
    input_image,
    prompt: str,
    duration: float,
    negative_prompt: str = DEFAULT_NEGATIVE_PROMPT,
    seed: int = 42,
    randomize_seed: bool = True,
    num_inference_steps: int = DEFAULT_NUM_INFERENCE_STEPS,
    cfg_guidance_scale: float = DEFAULT_CFG_GUIDANCE_SCALE,
    height: int = DEFAULT_HEIGHT,
    width: int = DEFAULT_WIDTH,
    progress=gr.Progress(track_tqdm=True)
):
    """Generate a video based on the given parameters."""
    try:
        # Randomize seed if checkbox is enabled
        current_seed = random.randint(0, MAX_SEED) if randomize_seed else int(seed)

        # Calculate num_frames from duration (using fixed 24 fps)
        frame_rate = 24.0
        num_frames = int(duration * frame_rate) + 1  # +1 to ensure we meet the duration

        # Create output directory if it doesn't exist
        output_dir = Path("outputs")
        output_dir.mkdir(exist_ok=True)
        output_path = output_dir / f"video_{seed}.mp4"

        # Handle image input
        images = []
        if input_image is not None:
            # Save uploaded image temporarily
            temp_image_path = output_dir / f"temp_input_{seed}.jpg"
            if hasattr(input_image, 'save'):
                input_image.save(temp_image_path)
            else:
                # If it's a file path already
                temp_image_path = input_image
            # Format: (image_path, frame_idx, strength)
            images = [(str(temp_image_path), 0, 1.0)]

        # Run inference - progress automatically tracks tqdm from pipeline
        pipeline(
            prompt=prompt,
            negative_prompt=negative_prompt,
            output_path=str(output_path),
            seed=current_seed,
            height=height,
            width=width,
            num_frames=num_frames,
            frame_rate=frame_rate,
            num_inference_steps=num_inference_steps,
            cfg_guidance_scale=cfg_guidance_scale,
            images=images,
            tiling_config=TilingConfig.default(),
        )

        return str(output_path), current_seed

    except Exception as e:
        import traceback
        error_msg = f"Error: {str(e)}\n{traceback.format_exc()}"
        print(error_msg)
        return None


# Create Gradio interface
with gr.Blocks(title="LTX-2 Video 🎥🔈") as demo:
    gr.Markdown("# LTX-2 🎥🔈: The First Open Source Audio-Video Model")
    gr.Markdown("State-of-the-art video & audio generation with Lightricks LTX-2 TI2V. Read more: [[model]](https://huggingface.co/Lightricks/LTX-2), [[code]](https://github.com/Lightricks/LTX-2)")
    with gr.Row():
        with gr.Column():
            input_image = gr.Image(
                label="Input Image (Optional)",
                type="pil",
            )

            prompt = gr.Textbox(
                label="Prompt",
                info="for best results - make it as elaborate as possible",
                value="Make this image come alive with cinematic motion, smooth animation",
                lines=3,
                placeholder="Describe the motion and animation you want..."
            )

            duration = gr.Slider(
                label="Duration (seconds)",
                minimum=1.0,
                maximum=10.0,
                value=3.0,
                step=0.1
            )

            generate_btn = gr.Button("Generate Video", variant="primary")

            with gr.Accordion("Advanced Settings", open=False):
                negative_prompt = gr.Textbox(
                    label="Negative Prompt",
                    value=DEFAULT_NEGATIVE_PROMPT,
                    lines=2
                )

                seed = gr.Slider(
                    label="Seed",
                    minimum=0,
                    maximum=MAX_SEED,
                    value=DEFAULT_SEED,
                    step=1
                )

                randomize_seed = gr.Checkbox(
                    label="Randomize Seed",
                    value=True
                )

                num_inference_steps = gr.Slider(
                    label="Inference Steps",
                    minimum=1,
                    maximum=100,
                    value=DEFAULT_NUM_INFERENCE_STEPS,
                    step=1
                )

                cfg_guidance_scale = gr.Slider(
                    label="CFG Guidance Scale",
                    minimum=1.0,
                    maximum=10.0,
                    value=DEFAULT_CFG_GUIDANCE_SCALE,
                    step=0.1
                )

                with gr.Row():
                    width = gr.Number(
                        label="Width",
                        value=DEFAULT_WIDTH,
                        precision=0
                    )
                    height = gr.Number(
                        label="Height",
                        value=DEFAULT_HEIGHT,
                        precision=0
                    )

        with gr.Column():
            output_video = gr.Video(label="Generated Video", autoplay=True)

    generate_btn.click(
        fn=generate_video,
        inputs=[
            input_image,
            prompt,
            duration,
            negative_prompt,
            seed,
            randomize_seed,
            num_inference_steps,
            cfg_guidance_scale,
            height,
            width,
        ],
        outputs=[output_video,seed]
    )

    # Add example
    gr.Examples(
        examples=[
            [
                "astronaut.jpg",
                "An astronaut hatches from a fragile egg on the surface of the Moon, the shell cracking and peeling apart in gentle low-gravity motion. Fine lunar dust lifts and drifts outward with each movement, floating in slow arcs before settling back onto the ground. The astronaut pushes free in a deliberate, weightless motion, small fragments of the egg tumbling and spinning through the air. In the background, the deep darkness of space subtly shifts as stars glide with the camera's movement, emphasizing vast depth and scale. The camera performs a smooth, cinematic slow push-in, with natural parallax between the foreground dust, the astronaut, and the distant starfield. Ultra-realistic detail, physically accurate low-gravity motion, cinematic lighting, and a breath-taking, movie-like shot.",
                5.0,
            ],
            [
                "kill_bill.jpeg",
                "A low, subsonic drone pulses as Uma Thurman's character, Beatrix Kiddo, holds her razor-sharp katana blade steady in the cinematic lighting. A faint electrical hum fills the silence. Suddenly, accompanied by a deep metallic groan, the polished steel begins to soften and distort, like heated metal starting to lose its structural integrity. Discordant strings swell as the blade's perfect edge slowly warps and droops, molten steel beginning to flow downward in silvery rivulets while maintaining its metallic sheen—each drip producing a wet, viscous stretching sound. The transformation starts subtly at first—a slight bend in the blade—then accelerates as the metal becomes increasingly fluid, the groaning intensifying. The camera holds steady on her face as her piercing eyes gradually narrow, not with lethal focus, but with confusion and growing alarm as she watches her weapon dissolve before her eyes. She whispers under her breath, voice flat with disbelief: 'Wait, what?' Her heartbeat rises in the mix—thump... thump-thump—as her breathing quickens slightly while she witnesses this impossible transformation. Sharp violin stabs punctuate each breath. The melting intensifies, the katana's perfect form becoming increasingly abstract, dripping like liquid mercury from her grip. Molten droplets fall to the ground with soft, bell-like pings. Unintelligible whispers fade in and out as her expression shifts from calm readiness to bewilderment and concern, her heartbeat now pounding like a war drum, as her legendary instrument of vengeance literally liquefies in her hands, leaving her defenseless and disoriented. All sound cuts to silence—then a single devastating bass drop as the final droplet falls, leaving only her unsteady breathing in the dark.",
                5.0,
            ]
        ],
        fn=generate_video,
        inputs=[input_image, prompt, duration],
        outputs = [output_video,seed],
        label="Example",
        cache_examples=True,
        cache_mode="lazy",
    )

css = '''
.gradio-container .contain{max-width: 1200px !important; margin: 0 auto !important}
'''
if __name__ == "__main__":
    demo.launch(theme=gr.themes.Citrus())