Veo 3.1
Veo 3.1 generates four, six or eight second clips and its audio is always on, with no option to turn it off. It reaches 4K, but only on the eight second clip, and it takes up to three reference images.
- four, six or eight seconds
- audio always on
- three reference images
Last checked: This is a reference page. It is re-checked against the vendor sources and updated when a new version ships. What changed
Eight seconds, and the three conditions printed next to it
Google model table gives three lengths: four, six and eight seconds. Eight comes with a condition, and the same table writes it down: eight seconds only if the output is 1080p or 4k, or if you are using reference images. Resolution works the same way round: 1080p and 4k are available on that eight second clip only.
So this model 4K and Kling 4K are not the same offer. Kling gives you 4K at any length; Veo gives it at its own ceiling. Both take the resolution column outright in our table, and this page is where the difference belongs.
Extension, which is the real route to a longer video
Veo extends a video it generated earlier: seven seconds at a time, up to twenty times. On paper that is a long video. In practice there is a constraint the documentation states plainly: while extending, the output is 720p only. So you get either the long video or the 4K, not both.
Three reference images
The reference ceiling is three images, and the documentation notes the feature is on the 3.1 models only. Three, against fifty for Seedance 2.5 and seven for Kling, is the lowest number in our table. It is enough for "put this character in this scene". It is not enough to build a consistent world with several characters and several products in it.
Why it is still what many teams pick
Because it is the only model in this table available through a public, documented API with an ordinary key, and its documentation can be read without an account. For a team putting video generation inside its own product, that one thing usually outweighs a clip twice as long.
Specifications
| Model ID | veo-3.1-generate-preview Source |
|---|---|
| Input | text, image Source |
| Output | video, audio Source |
| Available on | Gemini API, Runway API Source |
| Longest clip in one pass | 8 seconds Source |
| Resolution ceiling | 4K Source |
| Vertical resolution | 2,160 lines of vertical resolution Source |
| Native audio | yes Source |
| Reference inputs | 3 reference inputs Source |
Using it from Iran
We check this ourselves from an Iranian connection, because no vendor documents it and every listicle guesses.
- Reachable
- blocked
- Payment
- no working route
- Free tier
- no
- Measured on
How we checked: We opened Google supported-countries list ourselves today and read it: the list jumps from Indonesia straight to Iraq, and Iran is not on it. That is reading a page, not measuring a network; a direct test from inside Iran has not been run yet.
What it is good at
- Audio is always on, so there is no separate step to add it
- 4K on the eight second clip, which only Kling matches in this table
- Seven second extensions, up to twenty of them, on a video it generated itself
- Open, readable documentation, on Google public API
Where it falls short
- Eight seconds is the ceiling, and the shortest length in this table.
- 4K and 1080p exist only on the eight second clip, not at four or six seconds.
- An extended output is 720p only, so a long video and 4K cannot be combined.
- Three reference images is the lowest count in our table.
- Iran is not on Google supported-countries list and there is no official route.
Our take
If video generation has to live inside software you are building, this is the cleanest path in and the documentation reads in half an hour. If the finished output matters more than the route to it, eight seconds and three references tie your hands quickly.
Questions people actually ask
How long a video does Veo 3.1 generate
Four, six or eight seconds. Eight is available only when the output is 1080p or 4k, or when you use reference images.
Can Veo make a longer video
Through extension, yes: seven seconds at a time, up to twenty times. But an extended output is 720p only, so a long video does not come out in 4K.
Can Veo be used from Iran
Not officially. Iran is not on Google supported-countries list; we read that list ourselves today. We sell no accounts and recommend no circumvention.
Sources
- Google, Veo documentation in the Gemini API vendor source 12 August 2026
- Google, Gemini API model list vendor source 12 August 2026
- Where you can use the Gemini web app vendor source 12 August 2026
- Runway API pricing, per second of output vendor source 12 August 2026