Canonical page: https://mixerai.org/en/knowledge/compare/kling-4-0-vs-heygen-video/ Prices on this page are live: current values come from https://mixerai.org/api/knowledge/prices?lang=en. A dash means the value did not load. [Mixer AI](https://mixerai.org/en/) › [Knowledge Base](https://mixerai.org/en/knowledge/) › [Comparison](https://mixerai.org/en/knowledge/compare/) › Kling 4.0 vs HeyGen Video: specs and price # Kling 4.0 vs HeyGen Video: specs and price Kling 4.0 — resolutions: 720p / 1080p; maximum duration: 30 s. [Try it on Mixer AI](https://mixerai.org/en/#/canvas?dl=kb_kling-4-0-vs-heygen-video) ## When to choose Kling 4.0 and when HeyGen Video ### Kling 4.0 - Resolutions: 720p / 1080p vs 768p for HeyGen Video - Maximum duration: 30 s vs 15 s for HeyGen Video - Generation modes: from text / from first and last frames / from references vs from text for HeyGen Video - First frame: Yes vs No for HeyGen Video ### HeyGen Video - Prompt limit: 32,000 characters vs 8,000 characters for Kling 4.0 - Aspect ratios: 6 vs 5 for Kling 4.0 ## Key differences Kling 4.0: A clip of up to 30 seconds from text and references or from a chain of keyframes: named characters, voice samples and exact frames. HeyGen Video: Creates videos with sound from a text prompt or a single source image. ## Specifications | Spec | Kling 4.0 | HeyGen Video | Model variants | Reference / Keyframes | HeyGen Video | Generation modes | from text / from first and last frames / from references | from text | First frame | Yes | No | Last frame | Yes | No | Input photos | up to 8 | up to 1 | Input videos | up to 5 | No | Input audio files | up to 3 | No | Input video length | 2–30 s | No | Minimum duration | 3 s | 5 s | Maximum duration | 30 s | 15 s | Resolutions | 720p / 1080p | 768p | Aspect ratios | 9:16 / 16:9 / 1:1 / auto / 21:9 | 9:16 / 16:9 / 1:1 / 4:3 / 3:4 / 21:9 | Prompt limit | 8,000 characters | 32,000 characters | Price, 1 s (different quality) | — coins · 720p | — coins · 768p There is no shared resolution for a direct price comparison, so each price includes its setting and is not highlighted as cheaper. ## What to compare visually For a fair A/B test, use the same scene and, where both modes allow it, the same first frame. Inspect motion continuity, character and object consistency, physics and contacts, camera behavior, temporal deformation, in-clip cuts and audio synchronization. ## What to inspect with Kling 4.0 A clip of up to 30 seconds from text and references or from a chain of keyframes: named characters, voice samples and exact frames. - Text and references: up to 10 reference photos and 5 videos, up to 7 characters (2–4 photos or one 3–8 second video clip each) and up to 3 voice samples. The Video sound switch applies only to reference videos. - Keyframes: a first frame, a last frame and up to 8 middle frames. The total number of frames depends on the duration and never exceeds 10. - The modes do not mix: Keyframes accepts no video, and characters and voices belong only to Text and references mode. - A hero photo must be at least 300 pixels on the short side; a video character needs at least 700 pixels and one continuous shot. ## What to inspect with HeyGen Video Creates videos with sound from a text prompt or a single source image. - Text: the result is created from a written description. - Every available setting is shown in the Studio form before launch, and the price follows them. - The result length is 5 to 15 seconds. - At most 1 photo as input. ## How to run a fair comparison - Fix the scene, the first frame (if both models accept one), the duration and the resolution. - Judge motion, not stills: faces, hands and objects should hold across the whole clip and at cuts. - If sound matters, listen to it separately: dialogue, effects and lip sync differ between models. - Price a finished clip, not a second: the per-second rate times your real duration, rounded up once. ## Sources Prices, availability and specifications come from the Mixer AI catalog. This is not an independent test: try both models on the same task before choosing. - [Prices and availability — Mixer AI catalog](https://mixerai.org/knowledge/catalog.json) ## What we compare [ Kling 4.0 A clip of up to 30 seconds from text and references or from a chain of keyframes: named characters, voice samples and exact frames. ](https://mixerai.org/en/knowledge/video/kling-4-0/) [ HeyGen Video Creates videos with sound from a text prompt or a single source image. ](https://mixerai.org/en/knowledge/video/heygen-video/) ## FAQ Which is cheaper: Kling 4.0 or HeyGen Video? The models use different settings, so a direct price comparison would be misleading: the prices of Kling 4.0 and HeyGen Video are in the table, so compare for the mode you need. How does Kling 4.0 differ from HeyGen Video? Kling 4.0 — resolutions: 720p / 1080p; maximum duration: 30 s; first frame: Yes. How should I compare Kling 4.0 and HeyGen Video fairly? Fix the scene, first frame, duration and resolution. Watch the motion across the whole clip and listen to the sound separately. Price the finished clip, not one second. Are both models available in Mixer AI? Yes. Both models are in the Mixer AI video catalog; the launch button on the page opens Canvas on a computer and the Studio on a phone. The page exists only for models in the current catalog. Which model is better? There is no single winner. First rule out the model that lacks the duration, first or last frame, sound or resolution you need, then compare clips on your own scene. The table highlights only measurable differences. ## See also [Kling AI Avatar vs HeyGen Video: specs and price→](https://mixerai.org/en/knowledge/compare/kling-avatar-vs-heygen-video/) [Kling 4.0 vs Kling 2.1: specs and price→](https://mixerai.org/en/knowledge/compare/kling-4-0-vs-kling-2-1/) [Gemini Omni 1.0 Flash vs HeyGen Video: specs and price→](https://mixerai.org/en/knowledge/compare/gemini-omni-1-0-flash-vs-heygen-video/) [Gemini Omni 1.1 Flash vs HeyGen Video: specs and price→](https://mixerai.org/en/knowledge/compare/gemini-omni-1-1-flash-vs-heygen-video/) [Try it on Mixer AI](https://mixerai.org/en/#/canvas?dl=kb_kling-4-0-vs-heygen-video)