LTXVDurationPredictor - ComfyUI Built-in Node Documentation - ComfyUI

This node predicts the natural shot duration for a text prompt using an LTX 2.4 duration head loaded with ModelPatchLoader, then snaps the result to the VAE’s 8k+1 frame grid. The prediction is converted into a frame count using the selected frame rate and the minimum and maximum duration limits.

Inputs

Parameter	Description	Data Type	Required	Range
`model`	The model used to preprocess the text embeddings and run the duration head.	MODEL	Yes	N/A
`positive`	The conditioning that provides the prompt’s text embeddings and metadata for the duration prediction.	CONDITIONING	Yes	N/A
`duration_head`	LTX 2.4 duration head loaded with ModelPatchLoader. Must be an LTX duration head.	MODEL_PATCH	Yes	N/A
`frame_rate`	Frame rate in frames per second used to convert seconds to frames (default: 24.0).	FLOAT	Yes	1.0 to 120.0
`min_seconds`	Minimum duration in seconds used when converting the prediction to a frame count (default: 1.0).	FLOAT	Yes	0.5 to 120.0
`max_seconds`	Maximum duration in seconds used when converting the prediction to a frame count (default: 20.0).	FLOAT	Yes	0.5 to 120.0

Note: The duration_head input must be a model patch containing an LTX duration head. If the connected model patch is not an LTX duration head, the node raises a ValueError. Only the first conditioning entry is used — if positive contains a batch of more than one prompt, the node evaluates just the first one.

Outputs

Output Name	Description	Data Type
`num_frames`	The predicted duration converted to a number of frames and snapped to the VAE’s 8k+1 frame grid.	INT
`seconds`	Raw (unclamped) predicted duration. This is the value before snapping to the frame grid.	FLOAT

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