How long can a Gemini Omni Flash video be?

Exact to a rounding of about a hundredth of a second. Asking for 3 seconds yields a file measured at 3.008 s, and the token accounting matches precisely — a 3-second clip consumes exactly three seconds' worth of video tokens. That matters because the price is linear in duration: half the length is half the bill.

It also means a draft pass is genuinely cheap. Testing a shot at 3 seconds costs $0.30; committing to the full 10 seconds costs $1.00. There is no quality penalty for the short version — the same model, same resolution, just fewer frames.

Omni Flash is a world model rather than a video generator with a soundtrack bolted on: it produces the picture and the sound in the same pass, lip-sync included. There is no flag to disable audio, and no price difference for it — it is already in the per-second rate.

You steer the audio the same way you steer everything else: in the prompt. A line like Audio/sound: rain on a metal roof, no music is honoured; there is no separate audio field. If you need a silent clip, generate normally and drop the track in your editor.

Cut several clips together. In practice that works better than it sounds, because Omni Flash accepts conversational editing: you make a clip, then ask for the next beat as a change to the one you already have, which keeps the character and the lighting consistent across shots.

The extend task exists in the API surface but the deployed 1.0 model rejects it — a correctly formed request fails with *This model does not support video extension* (the generation is free when it does). If you need a genuinely continuous long take, Veo 3.1 extensions are the tool: they add 7 seconds at a time, up to 148 seconds.

One more limit worth knowing before you plan around it: video-to-video editing keeps the source length. An edited clip has to come out the same duration as it went in, so editing is not a way to stretch a shot.