Kling 4.0 vs Veo 3.1 vs Seedance 2.5: Specs, Prices and Which to Use

Three model families define the top of AI video generation: Kuaishou’s Kling, Google’s Veo, and ByteDance’s Seedance. All three are now live on WaveSpeedAI, with Kling 4.0 available since October 2026.

This guide compares them on concrete specs: clip length, resolution, reference inputs, edit and extend endpoints, and how each is priced. It does not rank which model makes better video, because that depends on your prompts. Kling 3.0 and O3 are included as the previous Kling generation, since they still cover things Kling 4.0 on WaveSpeedAI does not, such as a native 4K tier.

Quick answer

Kling 4.0: 3 to 30 second clips at 720p or 1080p with synchronized stereo audio, up to 10 reference images, 5 reference videos and 3 reference audios, and dedicated video-edit and video-extend endpoints.
Seedance 2.5: the widest envelope. Up to 30-second clips, up to 4K, six aspect ratios, up to 30 reference images, plus editing and extension endpoints.
Veo 3.1: short, polished shots. 4, 6, or 8 seconds, up to 4K, native audio, 1 to 3 reference images, and a video-extend endpoint.
Kling 3.0 and O3: structured storytelling. Up to six shots per request, a native 4K tier, and reusable characters through Kling Elements.

Specs at a glance

Values reflect live model parameters on WaveSpeedAI.

	Kling 4.0	Veo 3.1	Seedance 2.5	Kling 3.0 / O3
Clip length	3 to 30 s (default 5)	4, 6, or 8 s	4 to 30 s	3 to 15 s
Resolution	720p or 1080p	Up to 4K	Up to 4K	4K tier
Aspect ratios	16:9, 9:16, 1:1, 21:9	16:9, 9:16	16:9, 9:16, 4:3, 3:4, 1:1, 21:9	16:9, 9:16, 1:1
Native audio	Yes, stereo, generated with the picture	Yes	Yes	Yes (Standard, Pro, 4K)
Reference inputs	Up to 10 images, 5 videos, 3 audios (15 files at most)	1 to 3 images	Up to 30 images, plus video and audio	Up to 3 Elements (3.0 image-to-video and O3); O3 adds up to 7 images and a video
First, last and in-between frames	First frame, optional last frame, optional keyframes (10 images at most)	First and last frame	Prompt and reference driven	Image-to-video
Edit existing video	Yes (video-edit)	No dedicated endpoint	Yes	Yes (O3)
Extend existing video	Yes (video-extend, 3 to 30 s added)	Yes	Yes	No dedicated endpoint
Multi-shot per request	Prompt-driven	Prompt-driven	Prompt-driven	Up to 6 shots
Faster tier	None on WaveSpeedAI	Veo 3.1 Fast, Veo 3.1 Lite	Seedance 2.5 Turbo	Kling 3.0 Turbo
Price basis	Per second of output (video-edit and reference videos: counted seconds)	Per second, by resolution and audio	Per second, by resolution or tier	Per second, by tier and audio

Two differences stand out. Kling 4.0 matches Seedance 2.5 on the 30-second ceiling but tops out at 1080p, while Veo 3.1 and Seedance 2.5 reach 4K. On references, Seedance 2.5 takes the most images (30), while Kling 4.0 caps images at 10 but lets you mix up to 5 videos and 3 audios.

How each family fits a workload

Kling 4.0: references, edits and extensions in one family

Kling 4.0 has five endpoints on WaveSpeedAI, all with 3 to 30 second clips, 720p or 1080p, and synchronized stereo audio:

Text-to-video: a prompt plus aspect ratio (16:9, 9:16, 1:1 or 21:9), resolution and duration.
Image-to-video: a required first frame, an optional last frame and optional in-between keyframes, up to 10 images in total.
Reference-to-video: up to 10 reference images, 5 reference videos and 3 reference audios, cited in the prompt as @Image1, @Video1 and @Audio1 in the order given. A keep_original_sound option keeps a reference video’s own sound.
Video edit: change a 3 to 30 second video with a prompt while keeping its scene, subject and motion. The original sound is kept by default.
Video extend: generate a new 3 to 30 second segment from the video’s last frame and get the original and the new segment joined, optionally steering toward a target last frame.

In our test, a 5-second clip of a red vintage convertible on a coastal road was edited into a snowy winter evening; the result kept the same car, driver and motion, added snow on the road and cliffs, and kept the audio. In another test, a 5-second sailboat-at-sunrise clip was extended by 5 seconds, and the boat and bay carried on while the camera rose to reveal a harbor, giving a 10-second clip with audio. These are two quick runs, not benchmarks.

Veo 3.1: short cinematic shots with sound

Veo 3.1 generates fixed 4, 6, or 8-second clips at up to 4K with native audio. The short, fixed lengths suit hero shots, social cutdowns, and B-roll where each clip is a single moment. When you need more time, Veo 3.1 text-to-video pairs with the video-extend endpoint, and Veo 3.1 reference-to-video keeps up to three subjects consistent. Veo 3.1 Fast and Lite cover drafts and high-volume work.

Seedance 2.5: long takes and asset-heavy briefs

Seedance 2.5 has the largest envelope of the three: 30-second clips, six aspect ratios, and up to 30 reference images alongside reference video and audio. Its video-edit and video-extend endpoints make it a fit for revise-and-extend workflows. E-commerce teams with multi-angle product sets and short-drama teams shooting long beats tend to land here.

Kling 3.0 and O3: scripted scenes and recurring characters

Kling 3.0 is built for storyboards: up to six shots in one request, with automatic or custom shot splitting, and a native 4K tier with the same inputs as Standard and Pro. Kling O3 adds reference-to-video and video editing, and Kling Elements, accepted by Kling 3.0 image-to-video and O3, keep characters consistent across a series.

Which one for which job

Most production teams route different jobs to different models. A starting point based on the specs above:

Job	Start with	Why
6 to 8-second hero shot at 4K	Veo 3.1	Fixed short lengths, up to 4K, native audio
15 to 30-second single take at 4K	Seedance 2.5	30-second clips and a 4K option
15 to 30-second single take at 1080p	Kling 4.0 or Seedance 2.5	Both reach 30 s; compare price and result on your prompt
Product clip from many photos	Seedance 2.5	Up to 30 reference images
Brief with reference videos and audio tracks	Kling 4.0	Up to 5 reference videos and 3 reference audios in one request
Keep a clip and change its setting or look	Kling 4.0 video-edit or Seedance 2.5 video-edit	Both keep the source clip as the starting point
Continue an approved clip	Kling 4.0 video-extend, Seedance 2.5 or Veo 3.1	All have an extend endpoint; Kling 4.0 adds up to 30 s
Start and end on specific frames	Kling 4.0 image-to-video	First frame, last frame and keyframes
Scripted ad with a shot list	Kling 3.0	Up to 6 shots per request
Series with a recurring character	Kling O3 with Elements	Reusable characters
Fast drafts	Veo 3.1 Fast, Seedance 2.5 Turbo, or Kling 3.0 Turbo	Faster tiers with the same request shape

Run the same prompt through two candidates in the WaveSpeedAI Video Generator before committing a job type to a model. Kling 4.0 has its own entry there with four modes: Generate, Reference, Edit and Extend, at video-generator?model=kling-4.0.

One routing table, one API

All three families share the same WaveSpeedAI request flow: submit to the model path, receive a prediction ID, poll for the result. That makes routing a lookup rather than three integrations:

ROUTES = {
    "hero_shot": "google/veo3.1/text-to-video",
    "long_take_4k": "bytedance/seedance-2.5/text-to-video",
    "long_take_1080p": "kwaivgi/kling-v4.0/text-to-video",
    "reference_brief": "kwaivgi/kling-v4.0/reference-to-video",
    "edit_clip": "kwaivgi/kling-v4.0/video-edit",
    "shot_list": "kwaivgi/kling-v3.0-pro/text-to-video",
    "character_series": "kwaivgi/kling-video-o3-pro/reference-to-video",
}

Each request is a POST to https://api.wavespeed.ai/api/v3/<model id>; the response carries a prediction ID that you poll at https://api.wavespeed.ai/api/v3/predictions/<id>/result. Moving a job type to another model is a one-line change.

Pricing

All three families are billed per second of generated video on WaveSpeedAI, with no subscription. Rates for Veo 3.1, Seedance 2.5 and Kling 3.0 depend on resolution or tier and on whether audio is enabled.

For Kling 4.0, at the time of writing, text-to-video, image-to-video and video-extend cost $0.157 per second at 720p and $0.235 per second at 1080p, so a 5-second 720p clip is $0.785 and a 10-second 1080p clip is $2.35. Reference-to-video without a reference video uses the same rates. With reference videos, and for video-edit, billing uses counted seconds (output length plus the longer of the output length and the total reference-video length, each capped at 30 s) at $0.094 per counted second at 720p and $0.141 at 1080p; reference audios are not charged. Always check the current numbers on the Kling 4.0, Veo 3.1, Seedance 2.5, and Kling 3.0 API pages.

Bottom line

There is no single best video model in 2026. Veo 3.1 is the short-shot specialist with a 4K option, Seedance 2.5 has the widest envelope, Kling 3.0 and O3 are the most structured for scripted and character-driven work, and Kling 4.0 combines 30-second clips with large reference limits and dedicated edit and extend endpoints at 720p and 1080p. Choose by the spec your job needs, then test on your own prompts; the Kling 4.0 collection lists all five endpoints.

Kuaishou has published its own overview of the 4.0 model at kling.ai; what is offered on WaveSpeedAI is the set of endpoints and limits listed above.

FAQ

Which is the best AI video model: Kling 4.0, Veo 3.1, or Seedance 2.5?

It depends on the job. Kling 4.0 offers 3 to 30 second clips at 720p or 1080p with up to 10 reference images, 5 reference videos and 3 reference audios, plus dedicated video-edit and video-extend endpoints. Seedance 2.5 offers 4 to 30 seconds, up to 4K and up to 30 reference images. Veo 3.1 offers 4, 6, or 8 second clips at up to 4K. Pick by the spec your job needs and test on your own prompts.

Which of the three supports the longest clips?

Kling 4.0 and Seedance 2.5 both reach 30 seconds per request (Kling 4.0 from 3 s, Seedance 2.5 from 4 s). Veo 3.1 generates 4, 6, or 8 seconds and offers a separate video-extend endpoint. Kling 4.0 also has a video-extend endpoint that adds 3 to 30 seconds to an existing clip.

Do all three generate audio?

Yes. Kling 4.0 generates synchronized stereo audio with the picture on all five of its WaveSpeedAI endpoints. Seedance 2.5 and Veo 3.1 also have a native audio option.

Does Kling 4.0 on WaveSpeedAI support 4K?

No. Kling 4.0 on WaveSpeedAI offers 720p and 1080p. If you need a native 4K tier, Kling 3.0 and O3, Veo 3.1 and Seedance 2.5 offer one.

How is Kling 4.0 priced?

Per second of generated video, with no subscription. At the time of writing, text-to-video, image-to-video and video-extend cost $0.157 per second at 720p and $0.235 per second at 1080p. Reference-to-video with reference videos and video-edit use a counted-second rule described on the Kling 4.0 API page, which always shows current prices.

Can I use all three through one API?

Yes. On WaveSpeedAI all three families use the same submit-and-poll request pattern, so you can route each job to a different model by changing the model path.