Raise warning and round down if Wan num_frames is not 4k + 1

[a-r-r-o-w]

Fixes#11163.

Raises a warning if the number of frames to be generated is not a multiple of 4K + 1. The reason for it being that way is because the VAE applies a 4x temporal downscaling/upscaling and the latents are created respecting that.

It is mentioned in the docs.

[Copilot]

Pull Request Overview

This pull request ensures that the number of frames passed to the WAN pipelines follows the required format (4 * k + 1).

• In src/diffusers/pipelines/wan/pipeline_wan_i2v.py, the num_frames parameter is added to the function signature and validated.
• In src/diffusers/pipelines/wan/pipeline_wan.py, similar changes are applied to enforce the frame constraint.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/diffusers/pipelines/wan/pipeline_wan_i2v.py	Added num_frames parameter and validation logic to enforce 4*k+1.
src/diffusers/pipelines/wan/pipeline_wan.py	Updated function signatures and added the same num_frames check to ensure consistency.

Comments suppressed due to low confidence (1)

src/diffusers/pipelines/wan/pipeline_wan_i2v.py:331

• Consider adding a check that num_frames is greater than or equal to 1 to ensure the validation accurately reflects a 4*k + 1 form where k >= 0.

if num_frames % 4 != 1:

[Copilot]

Consider enforcing that num_frames is at least 1 before applying the modulo check to handle negative values appropriately.

Suggested change

	raiseValueError(f"`height` and `width` have to be divisible by 16 but are {height} and {width}.")
	raiseValueError(f"`height` and `width` have to be divisible by 16 but are {height} and {width}.")
	ifnum_frames<1:
	raiseValueError("`num_frames` must be at least 1")

[HuggingFaceDocBuilderDev]

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[a-r-r-o-w]

@DN6 I've updated the PR to round down and raise a warning if num_frames is not of the form 4 * k + 1 instead of raising an error as discussed