LTX-影片

LTX-Video 是一種擴散 Transformer，旨在實現從文字和影像快速即時生成高解析度影片。LTX-Video 的主要特點是 Video-VAE。Video-VAE 具有更高的畫素到潛在空間壓縮比（1:192），這使得影片資料處理更高效，生成速度更快。為了支援並防止在生成過程中丟失更精細的細節，Video-VAE 解碼器執行潛在空間到畫素的轉換**和**最後的去噪步驟。

您可以在 Lightricks 組織下找到所有原始的 LTX-Video 檢查點。

以下示例演示瞭如何生成針對記憶體或推理速度進行最佳化的影片。

import torch
from diffusers import LTXPipeline, AutoModel
from diffusers.hooks import apply_group_offloading
from diffusers.utils import export_to_video

# fp8 layerwise weight-casting
transformer = AutoModel.from_pretrained(
    "Lightricks/LTX-Video",
    subfolder="transformer",
    torch_dtype=torch.bfloat16
)
transformer.enable_layerwise_casting(
    storage_dtype=torch.float8_e4m3fn, compute_dtype=torch.bfloat16
)

pipeline = LTXPipeline.from_pretrained("Lightricks/LTX-Video", transformer=transformer, torch_dtype=torch.bfloat16)

# group-offloading
onload_device = torch.device("cuda")
offload_device = torch.device("cpu")
pipeline.transformer.enable_group_offload(onload_device=onload_device, offload_device=offload_device, offload_type="leaf_level", use_stream=True)
apply_group_offloading(pipeline.text_encoder, onload_device=onload_device, offload_type="block_level", num_blocks_per_group=2)
apply_group_offloading(pipeline.vae, onload_device=onload_device, offload_type="leaf_level")

prompt = """
A woman with long brown hair and light skin smiles at another woman with long blonde hair.
The woman with brown hair wears a black jacket and has a small, barely noticeable mole on her right cheek.
The camera angle is a close-up, focused on the woman with brown hair's face. The lighting is warm and 
natural, likely from the setting sun, casting a soft glow on the scene. The scene appears to be real-life footage
"""
negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"

video = pipeline(
    prompt=prompt,
    negative_prompt=negative_prompt,
    width=768,
    height=512,
    num_frames=161,
    decode_timestep=0.03,
    decode_noise_scale=0.025,
    num_inference_steps=50,
).frames[0]
export_to_video(video, "output.mp4", fps=24)

注意事項

• 請參考 LTX-Video 倉庫中推薦的生成設定。

  • Transformer、VAE 和文字編碼器推薦的資料型別是 torch.bfloat16。VAE 和文字編碼器也可以是 torch.float32 或 torch.float16。
  • 對於 LTX-Video 的引導蒸餾變體，將 guidance_scale 設定為 1.0。對於任何其他模型，guidance_scale 應設定得更高，例如 5.0，以獲得良好的生成質量。
  • 對於時間步感知 VAE 變體（LTX-Video 0.9.1 及以上版本），將 decode_timestep 設定為 0.05，將 image_cond_noise_scale 設定為 0.025。
  • 對於支援在多個條件影像和影片之間進行插值的變體（LTX-Video 0.9.5 及以上版本），請使用相似的影像和影片以獲得最佳結果。偏離條件輸入可能會導致生成的影片中出現 abrupt transitionts。

• LTX-Video 0.9.7 包含一個空間潛在上取樣器和一個 13B 引數的 Transformer。在推理過程中，首先快速生成低解析度影片，然後進行上取樣和精細化。

  顯示示例程式碼

  已複製

  import torch
  from diffusers import LTXConditionPipeline, LTXLatentUpsamplePipeline
  from diffusers.pipelines.ltx.pipeline_ltx_condition import LTXVideoCondition
  from diffusers.utils import export_to_video, load_video
  
  pipeline = LTXConditionPipeline.from_pretrained("Lightricks/LTX-Video-0.9.7-dev", torch_dtype=torch.bfloat16)
  pipeline_upsample = LTXLatentUpsamplePipeline.from_pretrained("Lightricks/ltxv-spatial-upscaler-0.9.7", vae=pipeline.vae, torch_dtype=torch.bfloat16)
  pipeline.to("cuda")
  pipe_upsample.to("cuda")
  pipeline.vae.enable_tiling()
  
  def round_to_nearest_resolution_acceptable_by_vae(height, width):
      height = height - (height % pipeline.vae_temporal_compression_ratio)
      width = width - (width % pipeline.vae_temporal_compression_ratio)
      return height, width
  
  video = load_video(
      "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input-vid.mp4"
  )[:21]  # only use the first 21 frames as conditioning
  condition1 = LTXVideoCondition(video=video, frame_index=0)
  
  prompt = """
  The video depicts a winding mountain road covered in snow, with a single vehicle 
  traveling along it. The road is flanked by steep, rocky cliffs and sparse vegetation. 
  The landscape is characterized by rugged terrain and a river visible in the distance. 
  The scene captures the solitude and beauty of a winter drive through a mountainous region.
  """
  negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"
  expected_height, expected_width = 768, 1152
  downscale_factor = 2 / 3
  num_frames = 161
  
  # 1. Generate video at smaller resolution
  # Text-only conditioning is also supported without the need to pass `conditions`
  downscaled_height, downscaled_width = int(expected_height * downscale_factor), int(expected_width * downscale_factor)
  downscaled_height, downscaled_width = round_to_nearest_resolution_acceptable_by_vae(downscaled_height, downscaled_width)
  latents = pipeline(
      conditions=[condition1],
      prompt=prompt,
      negative_prompt=negative_prompt,
      width=downscaled_width,
      height=downscaled_height,
      num_frames=num_frames,
      num_inference_steps=30,
      decode_timestep=0.05,
      decode_noise_scale=0.025,
      image_cond_noise_scale=0.0,
      guidance_scale=5.0,
      guidance_rescale=0.7,
      generator=torch.Generator().manual_seed(0),
      output_type="latent",
  ).frames
  
  # 2. Upscale generated video using latent upsampler with fewer inference steps
  # The available latent upsampler upscales the height/width by 2x
  upscaled_height, upscaled_width = downscaled_height * 2, downscaled_width * 2
  upscaled_latents = pipe_upsample(
      latents=latents,
      output_type="latent"
  ).frames
  
  # 3. Denoise the upscaled video with few steps to improve texture (optional, but recommended)
  video = pipeline(
      conditions=[condition1],
      prompt=prompt,
      negative_prompt=negative_prompt,
      width=upscaled_width,
      height=upscaled_height,
      num_frames=num_frames,
      denoise_strength=0.4,  # Effectively, 4 inference steps out of 10
      num_inference_steps=10,
      latents=upscaled_latents,
      decode_timestep=0.05,
      decode_noise_scale=0.025,
      image_cond_noise_scale=0.0,
      guidance_scale=5.0,
      guidance_rescale=0.7,
      generator=torch.Generator().manual_seed(0),
      output_type="pil",
  ).frames[0]
  
  # 4. Downscale the video to the expected resolution
  video = [frame.resize((expected_width, expected_height)) for frame in video]
  
  export_to_video(video, "output.mp4", fps=24)

• LTX-Video 0.9.7 蒸餾模型經過引導和時間步蒸餾，以加速生成。它需要將 guidance_scale 設定為 1.0，並且 num_inference_steps 應設定在 4 到 10 之間以獲得良好的生成質量。您還應使用以下自定義時間步以獲得最佳結果。

  • 為上取樣做準備的基礎模型推理：[1000, 993, 987, 981, 975, 909, 725, 0.03]。
  • 上取樣：[1000, 909, 725, 421, 0]。
  顯示示例程式碼

  已複製

  import torch
  from diffusers import LTXConditionPipeline, LTXLatentUpsamplePipeline
  from diffusers.pipelines.ltx.pipeline_ltx_condition import LTXVideoCondition
  from diffusers.utils import export_to_video, load_video
  
  pipeline = LTXConditionPipeline.from_pretrained("Lightricks/LTX-Video-0.9.7-distilled", torch_dtype=torch.bfloat16)
  pipe_upsample = LTXLatentUpsamplePipeline.from_pretrained("Lightricks/ltxv-spatial-upscaler-0.9.7", vae=pipeline.vae, torch_dtype=torch.bfloat16)
  pipeline.to("cuda")
  pipe_upsample.to("cuda")
  pipeline.vae.enable_tiling()
  
  def round_to_nearest_resolution_acceptable_by_vae(height, width):
      height = height - (height % pipeline.vae_temporal_compression_ratio)
      width = width - (width % pipeline.vae_temporal_compression_ratio)
      return height, width
  
  prompt = """
  artistic anatomical 3d render, utlra quality, human half full male body with transparent 
  skin revealing structure instead of organs, muscular, intricate creative patterns, 
  monochromatic with backlighting, lightning mesh, scientific concept art, blending biology 
  with botany, surreal and ethereal quality, unreal engine 5, ray tracing, ultra realistic, 
  16K UHD, rich details. camera zooms out in a rotating fashion
  """
  negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"
  expected_height, expected_width = 768, 1152
  downscale_factor = 2 / 3
  num_frames = 161
  
  # 1. Generate video at smaller resolution
  downscaled_height, downscaled_width = int(expected_height * downscale_factor), int(expected_width * downscale_factor)
  downscaled_height, downscaled_width = round_to_nearest_resolution_acceptable_by_vae(downscaled_height, downscaled_width)
  latents = pipeline(
      prompt=prompt,
      negative_prompt=negative_prompt,
      width=downscaled_width,
      height=downscaled_height,
      num_frames=num_frames,
      timesteps=[1000, 993, 987, 981, 975, 909, 725, 0.03],
      decode_timestep=0.05,
      decode_noise_scale=0.025,
      image_cond_noise_scale=0.0,
      guidance_scale=1.0,
      guidance_rescale=0.7,
      generator=torch.Generator().manual_seed(0),
      output_type="latent",
  ).frames
  
  # 2. Upscale generated video using latent upsampler with fewer inference steps
  # The available latent upsampler upscales the height/width by 2x
  upscaled_height, upscaled_width = downscaled_height * 2, downscaled_width * 2
  upscaled_latents = pipe_upsample(
      latents=latents,
      adain_factor=1.0,
      output_type="latent"
  ).frames
  
  # 3. Denoise the upscaled video with few steps to improve texture (optional, but recommended)
  video = pipeline(
      prompt=prompt,
      negative_prompt=negative_prompt,
      width=upscaled_width,
      height=upscaled_height,
      num_frames=num_frames,
      denoise_strength=0.999,  # Effectively, 4 inference steps out of 5
      timesteps=[1000, 909, 725, 421, 0],
      latents=upscaled_latents,
      decode_timestep=0.05,
      decode_noise_scale=0.025,
      image_cond_noise_scale=0.0,
      guidance_scale=1.0,
      guidance_rescale=0.7,
      generator=torch.Generator().manual_seed(0),
      output_type="pil",
  ).frames[0]
  
  # 4. Downscale the video to the expected resolution
  video = [frame.resize((expected_width, expected_height)) for frame in video]
  
  export_to_video(video, "output.mp4", fps=24)

• LTX-Video 支援使用 load_lora_weights() 載入 LoRA。

  顯示示例程式碼

  已複製

  import torch
  from diffusers import LTXConditionPipeline
  from diffusers.utils import export_to_video, load_image
  
  pipeline = LTXConditionPipeline.from_pretrained(
      "Lightricks/LTX-Video-0.9.5", torch_dtype=torch.bfloat16
  )
  
  pipeline.load_lora_weights("Lightricks/LTX-Video-Cakeify-LoRA", adapter_name="cakeify")
  pipeline.set_adapters("cakeify")
  
  # use "CAKEIFY" to trigger the LoRA
  prompt = "CAKEIFY a person using a knife to cut a cake shaped like a Pikachu plushie"
  image = load_image("https://huggingface.co/Lightricks/LTX-Video-Cakeify-LoRA/resolve/main/assets/images/pikachu.png")
  
  video = pipeline(
      prompt=prompt,
      image=image,
      width=576,
      height=576,
      num_frames=161,
      decode_timestep=0.03,
      decode_noise_scale=0.025,
      num_inference_steps=50,
  ).frames[0]
  export_to_video(video, "output.mp4", fps=26)

• LTX-Video 支援從單個檔案載入，例如 GGUF 檢查點，使用 loaders.FromOriginalModelMixin.from_single_file() 或 loaders.FromSingleFileMixin.from_single_file()。

  顯示示例程式碼

  已複製

  import torch
  from diffusers.utils import export_to_video
  from diffusers import LTXPipeline, AutoModel, GGUFQuantizationConfig
  
  transformer = AutoModel.from_single_file(
      "https://huggingface.co/city96/LTX-Video-gguf/blob/main/ltx-video-2b-v0.9-Q3_K_S.gguf"
      quantization_config=GGUFQuantizationConfig(compute_dtype=torch.bfloat16),
      torch_dtype=torch.bfloat16
  )
  pipeline = LTXPipeline.from_pretrained(
      "Lightricks/LTX-Video",
      transformer=transformer,
      torch_dtype=torch.bfloat16
  )

LTXPipeline

>>> import torch
>>> from diffusers import LTXPipeline
>>> from diffusers.utils import export_to_video

>>> pipe = LTXPipeline.from_pretrained("Lightricks/LTX-Video", torch_dtype=torch.bfloat16)
>>> pipe.to("cuda")

>>> prompt = "A woman with long brown hair and light skin smiles at another woman with long blonde hair. The woman with brown hair wears a black jacket and has a small, barely noticeable mole on her right cheek. The camera angle is a close-up, focused on the woman with brown hair's face. The lighting is warm and natural, likely from the setting sun, casting a soft glow on the scene. The scene appears to be real-life footage"
>>> negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"

>>> video = pipe(
...     prompt=prompt,
...     negative_prompt=negative_prompt,
...     width=704,
...     height=480,
...     num_frames=161,
...     num_inference_steps=50,
... ).frames[0]
>>> export_to_video(video, "output.mp4", fps=24)

LTXImageToVideoPipeline

>>> import torch
>>> from diffusers import LTXImageToVideoPipeline
>>> from diffusers.utils import export_to_video, load_image

>>> pipe = LTXImageToVideoPipeline.from_pretrained("Lightricks/LTX-Video", torch_dtype=torch.bfloat16)
>>> pipe.to("cuda")

>>> image = load_image(
...     "https://huggingface.co/datasets/a-r-r-o-w/tiny-meme-dataset-captioned/resolve/main/images/8.png"
... )
>>> prompt = "A young girl stands calmly in the foreground, looking directly at the camera, as a house fire rages in the background. Flames engulf the structure, with smoke billowing into the air. Firefighters in protective gear rush to the scene, a fire truck labeled '38' visible behind them. The girl's neutral expression contrasts sharply with the chaos of the fire, creating a poignant and emotionally charged scene."
>>> negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"

>>> video = pipe(
...     image=image,
...     prompt=prompt,
...     negative_prompt=negative_prompt,
...     width=704,
...     height=480,
...     num_frames=161,
...     num_inference_steps=50,
... ).frames[0]
>>> export_to_video(video, "output.mp4", fps=24)

LTXConditionPipeline

>>> import torch
>>> from diffusers.pipelines.ltx.pipeline_ltx_condition import LTXConditionPipeline, LTXVideoCondition
>>> from diffusers.utils import export_to_video, load_video, load_image

>>> pipe = LTXConditionPipeline.from_pretrained("Lightricks/LTX-Video-0.9.5", torch_dtype=torch.bfloat16)
>>> pipe.to("cuda")

>>> # Load input image and video
>>> video = load_video(
...     "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input-vid.mp4"
... )
>>> image = load_image(
...     "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input.jpg"
... )

>>> # Create conditioning objects
>>> condition1 = LTXVideoCondition(
...     image=image,
...     frame_index=0,
... )
>>> condition2 = LTXVideoCondition(
...     video=video,
...     frame_index=80,
... )

>>> prompt = "The video depicts a long, straight highway stretching into the distance, flanked by metal guardrails. The road is divided into multiple lanes, with a few vehicles visible in the far distance. The surrounding landscape features dry, grassy fields on one side and rolling hills on the other. The sky is mostly clear with a few scattered clouds, suggesting a bright, sunny day. And then the camera switch to a winding mountain road covered in snow, with a single vehicle traveling along it. The road is flanked by steep, rocky cliffs and sparse vegetation. The landscape is characterized by rugged terrain and a river visible in the distance. The scene captures the solitude and beauty of a winter drive through a mountainous region."
>>> negative_prompt = "worst quality, inconsistent motion, blurry, jittery, distorted"

>>> # Generate video
>>> generator = torch.Generator("cuda").manual_seed(0)
>>> # Text-only conditioning is also supported without the need to pass `conditions`
>>> video = pipe(
...     conditions=[condition1, condition2],
...     prompt=prompt,
...     negative_prompt=negative_prompt,
...     width=768,
...     height=512,
...     num_frames=161,
...     num_inference_steps=40,
...     generator=generator,
... ).frames[0]

>>> export_to_video(video, "output.mp4", fps=24)

LTXLatentUpsamplePipeline

LTXPipelineOutput