Nonprofit donation appeal: a 15-second video from two Omni clips

A 15-second donation appeal needs two Gemini Omni Flash clips, because one request stops at 10 seconds: a 10-second opening and a 5-second ask. At 720p on Sume the pair costs $1.875 ($1.25 plus $0.625). Put the amount and the call to action in captions that you add yourself, not in the generated picture. Prices read 2026-10-08.

Appeals also raise a question that product clips do not: what is real. Read the watermark and disclosure section before you publish.

Structure of the two clips

Give the first clip the situation and the second the response. Keep both to one scene and describe the light and the sound.

• Clip A, 10 s: the problem, shown without faces of real people, for example an empty classroom or a quiet street.
• Clip B, 5 s: the response, such as a full classroom, with a place for the donate text.
• Use the last frame of Clip A as the image_url of Clip B so the two scenes share a setting.
• Write No dialogue in both, and record a human voiceover if you want a spoken ask.

Cost

Two clips, no re-rolls.

Watermark and disclosure

Google states that all Omni videos include a SynthID watermark. It is invisible to viewers and can be checked in tools such as the Gemini app, Search, Chrome or the SynthID Detector portal, per Google's SynthID page. That is provenance, not disclosure. For a charity, the safer practice is to say in the caption or description that the scenes are illustrative and AI-made, and to avoid generated people who look like real beneficiaries.

Google's Omni page also says content filters apply to prompts and output, and vary by region, so a sensitive subject may be refused or altered. If a clip is blocked on Sume, change the prompt rather than retrying the same text.

Joining the clips

Sume's Timeline can place the two clips in order and add a short fade. Omni's native sound will differ between clips, so lay one music bed under both, or mute the generated track and use your own.

Submitting the two clips

Submit clip A first. When it completes, extract its last frame and send that as the image_url of clip B. Google's Omni page also describes extending a clip by 10 seconds per turn, up to 40 seconds total, with previous_interaction_id; on Sume the catalog documents image-to-video, reference and edit modes, so the last-frame approach is the one to plan around.

Submit with an Idempotency-Key header so a retry after a dropped connection returns the original job instead of a second charge; the same key with a different payload returns 409. Then poll GET /v1/jobs/:id/status and fetch GET /v1/jobs/:id/result when it finishes.