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.

Extend the scene. Since September 2026 Omni Flash on BananaBanana is the 1.1 generation, and it has an extend task: open a finished clip, choose Extend, describe what happens next, and the model appends 3 to 10 seconds to the end of it. The whole source is read every time — a 13-second result of one extension goes back in as 13 seconds, not trimmed to 10 — so extensions chain, and the chain stops at 40 seconds. Reference images can bring a new subject into the continuation. Extension is billed on the full resulting length, so the last pass of a long chain costs as much as a clip of that length.

The original 1.0 generation, still available as Omni Flash 1.0, rejects the same task — a correctly formed request fails with *This model does not support video extension*. If you need a continuous take longer than 40 seconds, Veo 3.1 extensions add 7 seconds at a time up to 148 seconds, and Wan 3.0 renders 30 seconds in one run.

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 — extension is.