Designing a Testable Video-to-SFX Interface Contract

This is a public-interface design note, not a claim about VEME’s private code or model architecture. A page can reveal the user journey; it cannot reveal queues, storage, model selection, or production latency. That boundary still leaves enough to define useful frontend contracts.

Model the visible request

Represent an uploaded video, a sound description, and a revision identifier. Keep the description separate from the media asset so a user can change one without losing the other. The public VEME site describes an AI video and image workspace, while the sound-effect page shows a video upload step and a sound-description field.

Treat placement as reviewable state

An interface that says “complete” is not enough. A result should expose cue time, cue type, and whether it is an effect or an ambience bed. Suggested states are draft, queued, generating, ready, needs-review, and failed. These are design proposals for testing, not observed implementation details.

A small contract

type SfxRequest = {
  videoId: string;
  description: string;
  revision: number;
};

type Cue = { startMs: number; label: string; role: 'effect' | 'ambience' };

The Add Sound Effects to Video page positions matching as an action-to-frame problem. A testable result card should therefore show the cue list beside a preview, preserve the original request, and make retry semantics explicit.

Acceptance tests

• Refreshing the page does not erase the uploaded-clip reference.
• Editing the description creates a new revision rather than silently overwriting history.
• A cue at time zero remains visible and selectable.
• Failed generation explains the next safe action without inventing a cause.
• Audio controls expose text labels, keyboard focus, and a muted review path.

What remains outside the contract

Selectors, model quality, exact export formats, and timing tolerance need verification in the real editor. Do not turn illustrative fields into promises. Human review still covers rights, voice intelligibility, captions, and final loudness. The frontend win is simpler: every generated candidate should answer what changed, where the cue belongs, and who must approve it next.