Three alternative endings for a Short: cost at 360p to 4K

Three 8-second endings from Gemini Omni Flash 1.1 cost $0.90 at 360p and $3.00 at 720p through Sume. At 1080p they are $4.50 and at 4K $9.00. Each then needs a Timeline render at $0.10 per output minute to join it to your Short. The per-second rate is Sume's: the provider list price plus a 25% markup, from the repo pricing tables.

YouTube's Extend with AI feature, which adds a segment of about 8 seconds or less to an eligible Short, was reported in September 2025 by a third-party outlet (read 2026-10-03); this page prices the Sume alternative, not YouTube's. Model rules are in the Video Router doc.

What are the per-second rates?

The model takes 3 to 10 seconds, 360p, 720p, 1080p or 4K, and 16:9 or 9:16. Native audio is always on. The defaults are 8 seconds and 720p.

How should I spend it?

Draft at 360p, pick the best of the three, and rerun only that one at the final resolution. For a Short that will be watched on a phone, 720p is the model default and a sensible final; 4K is a large step in price for a vertical video. Confirm live rates in GET /v1/catalog before a batch, because these numbers can change.

How do I keep the ending on the same story?

Use the first frame of your last shot as image_url, optionally the planned final frame as end_image_url, and up to 10 reference_image_urls for character and product. Reference video is limited to 3 clips of at most 3 seconds each. The video_url edit mode cannot be combined with any of these, so it is for changing an existing clip, not for continuing a story.

What Sume does not do

There is no button that continues a Short from where YouTube's editor stops. You create the ending clip and splice it yourself with Timeline.