Gemini Omni extend video: Google's 40 s cap vs Sume's modes

Google's Gemini Omni can extend an existing video, but Sume's gemini-omni-flash-1.1 row has no extend mode. It routes four request shapes: text to video, image to video, reference to video and video edit. To go longer on Sume you chain clips yourself.

Google's behavior is from its Omni page and changelog; Sume's from the Video Router docs and catalog code, all read 2026-09-30.

What does Google's video extension do?

The Omni page says the model analyzes the input video to generate a 3 to 10 second continuation. Uploaded input videos must be 10 seconds or less, and the total extended length is capped at 40 seconds. The August 27, 2026 changelog lists "Video extension" among the features that arrived with general availability of gemini-omni-1.1-flash.

What does Sume's Omni row support instead?

Can a reference video stand in for extension?

Only loosely. reference_video_urls accepts up to 3 clips of at most 3 seconds each, and they guide the new clip rather than continuing the source. The edit mode changes an existing video and takes no duration, so it does not add length either.

How do I make a longer video on Sume?

Two documented routes. Chain clips: generate one clip, take its last frame, and send it as image_url on the next request; see Veo 3.1 extend vs chaining clips for the pattern. Or pick a model with a longer envelope: the docs say seedance-2.5 accepts 4 to 30 seconds. Chaining is your own loop, so continuity between clips is not guaranteed by the API.