Kling 4.0 Explained: 30-Second AI Video, 10 Keyframes, HDR, and What Else Is New
Kling AI has started beta testing Kling 4.0, its newest flagship video generation model, with a full launch planned for October.
It can generate up to 30 seconds of video in a single pass, accepts up to 10 keyframes, outputs two-channel stereo audio, and will add 10-bit HDR shortly. A lighter, cheaper sibling, Kling 4.0 Flash, launched alongside it.
This is the first major version bump for the Kling line since Kling 3.0 arrived on January 31, roughly eight months ago.
Below, we break down what changed, what Flash is for, how Kling 4.0 lines up against ByteDance's Seedance 2.5, and what is still unconfirmed.
In this article
- Kling 4.0 at a glance
- What's new in Kling 4.0
- Kling 4.0 Flash: the faster, cheaper option
- How Kling 4.0 compares with Seedance 2.5
- What we don't know yet
- FAQ
Kling 4.0 at a glance
| Kling 3.0 | Kling 4.0 | |
|---|---|---|
| Native clip length | Up to 15 seconds | Up to 30 seconds |
| Keyframe control | First and last frame only | Up to 10 keyframes |
| Reference inputs | Up to 3 Kling Elements | Up to 15 (images, videos, subjects) |
| Audio | Native audio | Two-channel stereo, improved lip sync |
| Output resolution | Standard, Pro and 4K tiers | 720p, 1080p, 4K |
| Dynamic range | — | 10-bit HDR coming soon |
| Aspect ratios | 3 (16:9, 9:16, 1:1) | 5, including 21:9 ultra-wide |
| Status | Live | Beta now, launching in October |
Kling AI groups the upgrade into three areas: audio-visual quality, creative control, and storytelling.
What's new in Kling 4.0
Audio-visual quality
Fast, chaotic motion is where most video models fall apart, so it is the fairest stress test. In Kling AI's multi-person fight demo, limbs and faces stay intact from frame to frame, and the hits land with a believable sense of weight and timing.
Other quality upgrades:
- Stereo sound. Kling 4.0 adds two-channel stereo output and improves lip-sync accuracy. In a complex rap demo, mouth movement matched the vocals closely, although the rhythm of the music itself still has room to improve.
- Ultra-wide framing. 21:9 is supported now, which matters for cinematic and ad formats.
- 10-bit HDR (coming soon). 10-bit is the standard used for streaming-grade productions. It can represent about 1.07 billion colors, 64 times more than the 8-bit SDR video most of us watch daily, which means smoother gradients and richer light-to-dark detail. HDR output is planned for 1080p and 4K.
- More languages and steadier text. Support now extends to German, French, Hindi and more. On-screen text has also been improved, and it stays stable during motion and scene changes.
Creative control
This is the biggest focus of the release.
- Longer prompts. Kling 4.0 can read prompts of up to 8,000 tokens, so you can describe a scene in far more detail. It also fills in gaps better: given a one-line idea such as an old man complaining about AI, it can write its own dialogue and build a coherent scene.
- Up to 15 reference inputs. These can include up to 10 images, up to 5 video clips (30 seconds combined), and subjects, with a voice you can assign to each. Upload several character references and the model keeps those characters and elements consistent across the finished video. On current Kling models, Kling Elements covers a similar idea: register a character once and reuse it across clips.
- Camera and motion references. Upload a reference clip and Kling 4.0 can copy its camera movement or have your character repeat its action. For commercial work, that means you can take the pacing and camera language of an existing ad and apply it to new footage. Motion transfer is already available today through motion control models.
- Video editing. You can add, change or remove subjects and backgrounds using text, images or subject references, and adjust things like weather or visual style. In one demo, a crowd was removed from a street scene after the fact. Text-instruction editing of existing footage is also available now across several video editing models.
Storytelling
- 30-second native generation. Twice the length of Kling 3.0, which gives an action or a scene change room to play out without cutting away.
- Extension to 2 minutes. Combined with the video continuation feature, clips can be extended to as long as two minutes. If you already work with continuation, the current video extend models show how that workflow fits together.
- Up to 10 keyframes. Kling 3.0 only accepted a first and last frame. With 10, you can pin down the opening, the ending and the plot beats in between. For comparison, today's first and last frame video models work with just those two anchors.
- Camera direction. The model understands pushes, pulls, pans, tracking shots, orbits and other standard camera moves, so you can direct shots the way a filmmaker would.
Kling 4.0 Flash: the faster, cheaper option
Kling 4.0 Flash trades length and fidelity for speed and cost:
| Capability | Kling 4.0 Flash |
|---|---|
| Text-to-video | ✓ |
| Image-to-video (first frame) | ✓ |
| Omni-reference (reference-to-video) | ✓ |
| Clip length | 3–20 seconds |
| Resolution | 720p |
| Dynamic range | 8-bit SDR |
Compared with the flagship's 30 seconds, 4K and 10-bit HDR, Flash is built for rapid drafts, concept testing and high-volume work where turnaround matters more than maximum quality. Flash is already open to Kling's top membership tier, which starts at ¥916 per month. If you need a fast, low-cost tier right now, the current Kling V3 Turbo models offer 720p and 1080p options.
How Kling 4.0 compares with Seedance 2.5
Both models now generate up to 30 seconds of video natively, so they meet at the same headline number. The differences are in the details:
| Kling 4.0 | Seedance 2.5 (ByteDance) | |
|---|---|---|
| Status | Beta, launching in October | Live |
| Clip length | 3–30 seconds | 4–30 seconds |
| Resolution | 720p / 1080p / 4K | 480p / 720p / 1080p / 4K |
| Dynamic range | 10-bit (HDR coming soon) | 10-bit |
| Keyframes | Up to 10 | First and last frame |
| Reference inputs | Up to 15 | Up to 50 |
| Aspect ratios | 5 (including 21:9) | 7 (including 21:9) |
| Audio | Two-channel stereo | Native audio generation |
| Editing | Yes (edit + extend) | Yes (edit + extend) |
How to read this table:
- Kling 4.0 leads on keyframe control. Ten keyframes versus two is a real advantage for anyone planning multi-beat scenes.
- Seedance 2.5 leads on references and formats. It accepts more reference inputs and more aspect ratios, and it is already available, while Kling 4.0 is still in beta.
- Audio isn't directly comparable. Kling emphasizes stereo output and lip sync; Seedance lists native audio generation. This table can't tell you which sounds better.
Spec sheets show what a model can do, not how well it does it. For a job-by-job decision guide covering ads, e-commerce and short drama, see the buyer's guide to Kling 4.0 vs Seedance 2.5 for commercial video, then run your own side-by-side tests with your actual prompts and reference material.
What we don't know yet
- API pricing. Kling AI hasn't published API pricing for either Kling 4.0 or Flash. Rates for models that are already live are listed on each model page, for example the Kling 3.0 API page.
- HDR timing. 10-bit HDR output is described as "coming soon," not live.
- Real-world consistency. The demos are curated. Independent testing will show how reliably Kling 4.0 handles long prompts, many references and full 30-second generations.
- Exact launch date. Kling AI says October but hasn't given a day.
If you're on Kling 3.0 today, the upgrade path and a day-one test plan are covered in Kling 4.0 vs Kling 3.0.
The bigger picture
Look at what the latest updates highlight: aspect ratio, audio channels, camera language. These are concepts from professional film and advertising production, not consumer novelty features. Video generation is being adopted for ads and short-form drama, and paying customers in those fields ask for more professional controls. That is the direction Kling 4.0 is moving in.
On the business side, Kling AI has also been raising capital. Reports say parent company Kuaishou announced a first independent funding round after the spin-off in July, with a second investment in August. The reported post-money valuation is about $18 billion, and the company plans to begin a Hong Kong listing process within the next 12 months. Treat these as reported figures and check them against the original company announcements.
FAQ
How long can a Kling 4.0 video be?
A single generation can run up to 30 seconds, which is twice the native length of Kling 3.0. Using the video continuation feature, you can extend a video to as long as 2 minutes.
When is Kling 4.0 available?
Kling 4.0 is in closed beta now, with the public launch planned for October. Kling 4.0 Flash is already available to Kling's highest membership tier.
Does Kling 4.0 support 4K and HDR?
It supports 720p, 1080p and 4K output. 10-bit HDR is on the roadmap for 1080p and 4K and has not launched yet.
How many keyframes does Kling 4.0 support?
Up to 10, compared with only a first and last frame in Kling 3.0. This lets you set the opening, the ending and key moments in between.
Is Kling 4.0 better than Seedance 2.5?
It depends on the job. Kling 4.0 offers more keyframe control, while Seedance 2.5 accepts more reference inputs, supports more aspect ratios and is already live. Both reach 30 seconds. Test both on your own material before deciding.
What is Kling 4.0 Flash?
A lighter version of Kling 4.0 with faster generation and better cost efficiency. It supports text-to-video, image-to-video from a first frame, and reference-to-video, with 3–20 second clips at 720p in 8-bit SDR.
Will Kling 4.0 be available on WaveSpeedAI?
WaveSpeedAI plans to add Kling 4.0 once API access opens. Until then, you can use the current Kling models and Seedance 2.5 through the same API.
Final thoughts
Kling 4.0 is a clear step toward video models that behave like production tools: longer takes, precise scene planning through keyframes, camera direction, stereo sound and broadcast-grade color. Seedance 2.5 keeps the competition close, and the real winner will be decided by hands-on results once Kling 4.0 goes public in October.
You don't have to wait to prepare. Try today's Kling and Seedance models side by side in the Kling, or wire them into your product through the API documentation, so your test set is ready when Kling 4.0 arrives.
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