Four AI video models lead the conversation in late 2026: ByteDance's Seedance 2.5, Kuaishou's Kling 4.0, Google's Veo 3.1 and Alibaba's Wan 3.0. All four generate video with sound from text or images, but they differ a lot in how long a clip can be, how much control you get, and what a clip costs.
This guide compares them on the things you choose a model for. All specs and prices are what you get on SeeVid, where all four run side by side with one credit balance — so you can test the same prompt on each.
The Short Answer
- Seedance 2.5 — the most control: 30-second takes, up to 30 reference images and 10 reference videos, plus video editing, extending and a draft mode. The priciest per second.
- Kling 4.0 — 30-second clips with built-in stereo sound at a mid-range price, with reference-to-video and video editing.
- Veo 3.1 — short 4–8 second clips, the only one of the four with 4K on SeeVid. Veo 3.1 Lite is the cheapest way to get an 8-second clip.
- Wan 3.0 — the lowest price per second for long clips, with references and the longest prompts.
Side-by-Side Comparison
| Seedance 2.5 | Kling 4.0 | Veo 3.1 Fast | Wan 3.0 | |
|---|---|---|---|---|
| Clip length | 4–30 s, or Auto | 3–30 s | 4, 6 or 8 s | 2–30 s, or Auto |
| Resolution | 480p, 720p, 1080p | 720p, 1080p | 720p, 1080p, 4K | 480p, 720p, 1080p |
| Native audio | Included | Included (stereo) | Optional (extra cost) | Included (can be turned off) |
| Image-to-video | First + last frame | Start + end frame | Up to 3 images | Yes |
| Reference images | Up to 30 | Up to 10 | — | Up to 10 |
| Reference videos | Up to 10 (30 s total) | Up to 5 (30 s total) | — | Up to 5 (15 s total) |
| Reference audio | Up to 10 | — | — | Up to 5 |
| Video editing | Yes | Yes | — | — |
| Video extending | Yes (forward or backward) | — | — | — |
| Draft → 1080p upgrade | Yes | — | — | — |
| Max prompt length | 10,000 chars | 2,500 chars | 2,000 chars | 20,000 chars |
| 5 s at 720p | 90 credits | 59 credits | 84 credits (8 s, with sound) | 37 credits |
| 30 s at 1080p | 976 credits | 528 credits | — | 449 credits |
1. Clip Length
Seedance 2.5, Kling 4.0 and Wan 3.0 all generate up to 30 seconds in one pass, which keeps characters, lighting and motion consistent across a full ad or story beat. Seedance 2.5 and Wan 3.0 also offer Auto, where the model picks a length that suits the prompt.
Veo 3.1 is built for short clips of 4, 6 or 8 seconds. For longer pieces you generate several clips and cut them together.
Winner for long takes: Seedance 2.5, Kling 4.0 and Wan 3.0 (tie on length); Seedance 2.5 can go further with its extender.
2. Resolution
Only Veo 3.1 Fast offers 4K on SeeVid. The other three top out at 1080p, which covers nearly all social and web video. If you need 4K from another model, generate at 1080p and use the AI Video Upscaler, or use Seedance 2.0, which also supports 4K.
Winner: Veo 3.1 for native 4K.
3. Sound
All four can generate audio with the picture — dialogue, effects and music. Kling 4.0 produces two-channel stereo with lip sync. On Veo 3.1 Fast, sound is optional and costs more when on (84 vs 56 credits for 8 seconds at 720p); on the others it is included in the price.
4. References and Consistency
This is where the models differ most.
- Seedance 2.5 accepts up to 30 images, 10 videos and 10 audio clips, tagged in the prompt as
@image1,@video1,@audio1. It's built for shots with several characters, products, outfits and locations at once. - Kling 4.0 and Wan 3.0 accept up to 10 images and 5 videos (Wan also takes 5 audio clips), enough for a few characters and a style.
- Veo 3.1 works from up to 3 images in image-to-video, with no separate reference mode.
Winner: Seedance 2.5, by a wide margin, for brand and character consistency.
5. Editing and Extending
Two of the four can change a video you already have:
- Seedance 2.5 — the AI Video Editor swaps products, backgrounds or styles in a 4–30 second clip while keeping the motion, and the AI Video Extender continues a clip forward or backward.
- Kling 4.0 — video edit rewrites a 3–30 second clip with up to 10 style images and keeps the original soundtrack.
Veo 3.1 and Wan 3.0 generate new clips only.
Winner: Seedance 2.5, the only one that both edits and extends.
6. Prompt Length
Long prompts matter for multi-shot clips. Wan 3.0 accepts 20,000 characters and Seedance 2.5 10,000, enough to script a 30-second sequence shot by shot. Kling 4.0 (2,500) and Veo 3.1 (2,000) need tighter prompts.
7. Price
| Length | Seedance 2.5 (720p) | Kling 4.0 (720p) | Veo 3.1 Fast (720p, sound) | Veo 3.1 Lite (720p) | Wan 3.0 (720p) |
|---|---|---|---|---|---|
| 5 s | 90 | 59 | — | — | 37 |
| 8 s | 145 | 94 | 84 | 30 | 60 |
| 15 s | 271 | 176 | — | — | 112 |
| 30 s | 542 | 352 | — | — | 224 |
Prices are in credits. Seedance 2.5 costs the most per second; its draft mode narrows the gap when you try several takes, because drafts cost the 480p price (42 credits for 5 seconds) and you upgrade only the one you keep. Details in the Seedance 2.5 pricing guide.
Winner on price: Veo 3.1 Lite for short clips, Wan 3.0 for long ones.
Which Model for Which Job?
| Job | Pick | Why |
|---|---|---|
| 30-second ad with products and a recurring character | Seedance 2.5 | 30 references, one continuous take |
| Swap a product or background in an existing clip | Seedance 2.5 or Kling 4.0 | Video editing |
| Make a clip longer | Seedance 2.5 | Video extending |
| Long clips on a budget | Wan 3.0 | Lowest cost per second up to 30 s |
| Long clip with stereo sound, mid-range price | Kling 4.0 | 30 s, sound included |
| Short 4K hero shot | Veo 3.1 Fast | Native 4K |
| Cheapest 8-second test | Veo 3.1 Lite | 30 credits at 720p |
| Detailed multi-shot script | Wan 3.0 or Seedance 2.5 | 20,000 / 10,000-character prompts |
A Practical Workflow
Many creators combine models instead of picking one:
- Explore ideas cheaply with Wan 3.0, Veo 3.1 Lite or Seedance 2.5 drafts.
- Produce the final shot with the model that fits it — Seedance 2.5 for reference-heavy work, Kling 4.0 or Wan 3.0 for long clips, Veo 3.1 for 4K.
- Fix and extend with Seedance 2.5's editor and extender instead of regenerating from scratch.
FAQ
Which is the best AI video model in 2026? It depends on the shot. Seedance 2.5 gives the most control, Veo 3.1 the only 4K, Wan 3.0 the lowest price for long clips and Kling 4.0 a balance of length, sound and price. Run the same prompt on two or three and compare.
Is Seedance 2.5 better than Kling 4.0? Seedance 2.5 offers more references, video extending and draft mode, and longer prompts. Kling 4.0 costs less per second and includes stereo sound. Both edit video and run up to 30 seconds.
Which model is cheapest? Veo 3.1 Lite for 8-second clips (30 credits at 720p) and Wan 3.0 for longer ones (37 credits for 5 seconds at 720p).
Can I use all four with one account? Yes. On SeeVid they share one credit balance; pick the model per generation in the AI Video Generator.
Where can I learn to prompt Seedance 2.5? See How to Use Seedance 2.5 for modes, settings and prompt formulas.
Conclusion
There is no single best model. Choose Seedance 2.5 when a shot needs many references, a 30-second take, or edits to existing footage; Kling 4.0 for long clips with stereo sound at a mid-range price; Veo 3.1 for short clips and 4K; and Wan 3.0 when you want long clips at the lowest cost.
Try them side by side on SeeVid with the same prompt.