HeyGen speaker rules as a checklist for a Sume face swap clip

What this post is and is not

HeyGen publishes plain-language guidance for source clips: speakers should face the camera within 45 degrees, only one person should speak at a time, and speakers should be within 10 feet of the camera. These come from HeyGen's video translation help article (read 2026-10-04) and apply to its own translation feature. Sume's face swap docs do not publish those three numbers, so this post does not claim they are Sume limits. It uses them as a sensible pre-check before you spend a Beta run.

What Sume documents for face swap

The Beta endpoint is POST /v1/models/sume/avatar-face-swap/v1.0/runs. Required fields are avatar_handle, video_url and quality, with no default quality. The video_url must be public HTTPS. Source clips are planned at about 4 to 15 seconds with usable audio, and prompts, transcripts and aspect ratio are unsupported. The result appears as resource_status and a video_url on media.sume.com.

None of this says what happens with several speakers or a face turned away, so the rules below are test-first advice, not guarantees.

Pre-check list

Run these before you submit. They are cheap to check by eye.

• One person on camera, facing the lens most of the time. HeyGen's 45 degree figure is a good ceiling to test against.
• One speaker at a time. HeyGen lists this as a rule for its own feature.
• Close enough that the face is large in frame; HeyGen says within 10 feet.
• Clip length inside Sume's planned 4 to 15 seconds, with audio you can hear clearly.
• A public HTTPS file URL, not a share page.

Both sets of rules

Where the two sources overlap, follow the stricter one.

A cautious test plan

Cut one clean 6 to 8 second clip that meets every row, submit it at the quality you intend to ship, and review the result before batching. If a clip that breaks one rule works, you have learned something about your footage, not about a documented limit; if it fails, the clip requirements post lists the documented rejection reasons. The Beta label in the docs means the behaviour may change, so keep the test clip around as a regression check.