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FastVideo CLI Inference

The FastVideo CLI exposes the same core inference controls as the Python API.

Basic Usage

Use either:

  1. --model-path + --prompt
  2. --model-path + --prompt-txt (batch prompts, one line per prompt)
  3. --config (JSON/YAML)
fastvideo generate --model-path Wan-AI/Wan2.1-T2V-1.3B-Diffusers \
  --prompt "A cat playing with a ball of yarn"

fastvideo generate --model-path Wan-AI/Wan2.1-T2V-1.3B-Diffusers \
  --prompt-txt prompts.txt

You cannot provide both --prompt and --prompt-txt in the same run.

View All Arguments

fastvideo generate --help

Arguments come from:

  • FastVideo runtime args (FastVideoArgs)
  • Sampling args (SamplingParam)
  • Pipeline config args (PipelineConfig)

Common Arguments

Parallelism

  • --num-gpus
  • --sp-size
  • --tp-size

Sampling

  • --num-frames
  • --height / --width
  • --num-inference-steps
  • --guidance-scale
  • --seed
  • --negative-prompt

Output

  • --output-path
  • --save-video / --no-save-video
  • --return-frames

Offloading and Performance

  • --dit-layerwise-offload
  • --use-fsdp-inference
  • --text-encoder-cpu-offload
  • --image-encoder-cpu-offload
  • --vae-cpu-offload
  • --enable-torch-compile
  • --torch-compile-kwargs

Using Config Files

fastvideo generate --config config.yaml

Config files can be JSON or YAML. CLI flags override config-file values.

Example config.yaml:

model_path: "FastVideo/FastHunyuan-diffusers"
prompt: "A capybara lounging in a hammock"
output_path: "outputs/"
num_gpus: 2
sp_size: 2
tp_size: 1
num_frames: 45
height: 720
width: 1280
num_inference_steps: 6
seed: 1024
dit_precision: "bf16"
vae_precision: "fp16"
vae_tiling: true
vae_sp: true
enable_torch_compile: false

Notes:

  • Use dit_precision / vae_precision (not precision).
  • Nested config objects are supported, for example vae_config and dit_config.

Examples

Simple generation:

fastvideo generate \
  --model-path FastVideo/FastHunyuan-diffusers \
  --prompt "A cat playing with a ball of yarn" \
  --num-frames 45 --height 720 --width 1280 \
  --num-inference-steps 6 --seed 1024 \
  --output-path outputs/

Config + CLI override:

fastvideo generate --config config.yaml --prompt "A panda skiing at sunset"