Kling 4.0 vs Seedance 2.5: Which AI Video Model to Use?

Both Kling 4.0 and Seedance 2.5 make clips of up to 30 seconds with sound in one generation. The main differences: Kling renders two-channel stereo while Seedance audio is mono; Kling's audio has no separate toggle while Seedance can render silent; Kling takes up to 15 reference assets against Seedance's 50; and Seedance 2.5 is fully available on BytePlus ModelArk, while Kling has announced API access only for 4.0 Flash and publishes no 4.0 API price (Kling's November 4 post; BytePlus docs, checked November 5, 2026).

Kling 4.0 opened to early access on September 28, 2026 and reached all users on October 15, 2026, according to Kling's launch post and October 26 news post (both checked November 5, 2026). Seedance 2.5 launched on July 31, 2026, per ByteDance Seed's launch post (checked November 5, 2026).

Short answer

• Pick Kling 4.0 for stereo sound, French or Hindi dialogue, a 4K line on the spec sheet, or keyframe and storyboard control. Flash, the 4.0 tier Kling says is on the API, stops at 20 seconds and 720p and has no start-and-end frames or multiple keyframes.
• Pick Seedance 2.5 for a silent clip, up to 50 reference files, a cheap 480p draft, or an API you can call today with published token prices.
• Our same-prompt runs, one each: all three Seedance 2.5 clips kept the requested setting. Against Kling's own samples, the tourist-desk clip showed the biggest gap: Kling's five lines came out clean and its shots followed the prompt's camera plan, while our Seedance clip's Mandarin was unrecognisable.
• API access: Seedance 2.5 is callable on BytePlus ModelArk with token prices; Kling has announced 4.0 Flash on the API but publishes no 4.0 model ID, endpoint or price.
• On OmniaKey, Seedance 2.5 is available as dreamina-seedance-2-5-260628; Kling 4.0 is not, and Kling 3.0 is.

Kling 4.0 vs Seedance 2.5 at a glance

Same prompts: Kling's samples next to our Seedance 2.5 runs

The Kling clips are Kling's own published samples: K-04 and K-05 come from its launch post and K-13 from its user guide (both checked November 5, 2026). We did not generate them. Our three clips are single runs of the same prompts through OmniaKey's API on November 5, 2026, with dreamina-seedance-2-5-260628 at 720P, 16:9, audio on, one run each and no retries. Kling chose which clips to publish, and its samples are about 1080p while ours are 720p; Kling's launch page states no duration for K-04, its clip runs 15 seconds, and we asked Seedance for 10.

An old man ranting about AI

Kling's prompt is six words:

An old man ranting about AI.

Kling 4.0: a white-haired man in a maroon cardigan sits in a leather armchair in a living room, with a smart speaker on the side table. He rants, turns to the speaker, then slumps back, in one continuous shot; the speaker's light ring glows while it talks, and at 7.5 seconds he points at it. In order, the audio is “They call this thing intelligent. It can't fix a faucet…”, the speaker's “Sorry, I didn't catch that.”, the man's “See, exactly what I'm talking about.”, the speaker's “Playing relaxing music.”, then acoustic guitar. Two voices.

Seedance 2.5: a white-haired man in a dark sweater stands in one spot in a book-lined study and shouts straight at the camera, in one continuous shot. The audio is “AI!”, “This so-called intelligence is just a bunch of gibberish!”, “It'll never replace real human thought!” One voice and no music.

Both turned six words into a full scene with a setting, a character and spoken lines. Kling's clip adds a second voice, the smart speaker, and ends on a joke: the speaker mishears and plays music.

A 7-second reunion on a UK street

K-05 is Kling's long-prompt demo, a single continuous 7-second shot:

A single continuous 7-second shot set in the UK. At dusk, two friends who haven’t seen each other in a long time meet at the corner of a quiet street, with people going about their everyday lives around them. They smile, walk quickly toward each other, and share a warm embrace. Their expressions and body movements feel natural. The handheld camera follows them with a slight, natural shake. Soft, warm lighting and a nostalgic film look. Include natural footsteps, street ambience, background music, and dialogue in English.

Kling 4.0: one continuous shot with white Georgian terraces, double yellow lines and muted dusk light. A man in a denim jacket and a man in a navy jacket walk toward each other and hug while passers-by and a cyclist go by behind them. The audio is “Oh my god, it's you!”, “Long time no see!”, lively synth music, crowd noise and laughter. Two voices.

Seedance 2.5: one continuous shot with brick terraces at dusk, an orange sky and lit street lamps. The camera swings round behind one man as his friend in a grey hoodie arrives, and they hug. The street is nearly empty apart from one distant walker. The audio is “Is that you?”, “Haha, it's been ages!”, a soft synth pad and laughter. Two voices.

Both kept to one continuous shot at dusk on a UK street, ended in a hug and added English dialogue and music. The prompt also asked for people going about their everyday lives around the pair: Kling's street has them, Seedance's is nearly empty.

Spanish and Chinese at a tourist information desk

K-13 asks for four timed blocks (0–3, 3–7, 7–11 and 11–15 seconds) and five lines: a Spanish question, its Chinese interpretation, a Chinese answer, its Spanish interpretation, and “Muchas gracias”. The lines are “¿Dónde está la estación de metro más cercana?”, “她想知道最近的地铁站在哪里。”, “沿这条路直走，步行大约五分钟就能到。”, “La estación de metro está a unos cinco minutos a pie. Siga recto por esta calle.” and “Muchas gracias”.

Kling 4.0: the tourist on the left with a backpack and a map, the interpreter in the middle with a lanyard, and a uniformed staff member on the right. Its four shots follow the prompt's camera plan: a three-shot, then the interpreter and the staff member, then the tourist and the interpreter over the map, then the three-shot again, with cuts at 5.2, 9.3 and 13.3 seconds. All five lines come out in the right language with the prompt's wording, in three voices and no music.

Seedance 2.5: three women at a white desk with kiosks behind them. It cuts at 3.9, 7.8 and 11.6 seconds, closer to the prompt's 3/7/11-second blocks than Kling's cuts, but every shot keeps all three women and only the framing changes; in the third, the woman in the navy blazer traces the way on the map. The two women behind the desk look alike, so the interpreter is hard to tell from the staff member. The opening Spanish question is partly garbled, the Chinese middle section is not recognisable Mandarin (two listening checks with two different models agreed), the Spanish directions are partly garbled, and “Muchas gracias” is clear. Two voices.

A cross-check: Kling's clip, cut at the same point and run through the same listening check, came out as clean Mandarin, so the check itself reads Mandarin.

One run per model shows what each clip did, not how often each model gets Chinese dialogue right.

Clip length and extension

Kling 4.0 generates 3 to 30 seconds in one pass, adjustable in 1-second steps, with a default of 10 seconds (Kling's user guide, checked November 5, 2026). Flash covers 3 to 20 seconds at 720p. Seedance 2.5 takes 4 to 30 seconds, or -1 to let the model choose, and defaults to -1 (BytePlus ModelArk's create-task page, checked November 5, 2026).

Kling's user guide describes extending a clip up to 2 minutes but marks it “Coming soon”; Kling's product page presents Video Extension as a live feature that runs forward and backward across multiple passes (both pages checked November 5, 2026). Treat the two-minute limit as announced, with shipping status unclear. Seedance 2.5's product page says a clip can be extended twice, its launch post says multiple rounds, and the API exposes an extend task with no published cap (BytePlus ModelArk docs, checked November 5, 2026). For a story longer than 30 seconds today, Seedance's extend task is the one with a live description in the API docs; check Kling's extension in your own account before you plan around it.

Audio and dialogue

Kling 4.0 renders two-channel stereo; Kling's own comparison with 3.0 lists “Single-channel” for 3.0 and “Two-channel stereo” for 4.0 (Kling's September 30 post, checked November 5, 2026). Seedance 2.5's generated audio is mono, “regardless of the number of channels of the input audio”, per BytePlus ModelArk's create-task page (checked November 5, 2026). In the files we measured, Kling's K-04 and K-05 samples have a clear left-right difference, K-13's dialogue sits mostly in the centre, and all three Seedance files have near-identical channels, which matches the mono note.

The switch differs too. Kling's own FAQ says “Audio-visual synchronization and Smart Storyboard are enabled by default and have no separate toggles” (user guide, checked November 5, 2026). Seedance's generate_audio: false returns a silent video (BytePlus create-task page, checked November 5, 2026).

Kling lists nine dialogue languages: Chinese, English, Japanese, Korean, Spanish, Portuguese, German, French and Hindi (user guide, checked November 5, 2026). Seedance's ModelArk docs list 11: Chinese, English, Spanish, Indonesian, Malay, Thai, Arabic, Portuguese, Vietnamese, Japanese and Korean. BytePlus's Lumina page claims “10+ languages, including Chinese, English, French, Spanish, Hindi”, so French and Hindi appear only on that marketing page (both checked November 5, 2026).

Kling's launch post promises “improved lip-sync accuracy” alongside stereo (September 30, checked November 5, 2026). BytePlus says creators can work in their native language and get “accurate lip-sync and localized content” (Lumina page, checked November 5, 2026). In our one tourist-desk run, Kling's sample delivered all five lines and our Seedance clip did not, which is the kind of result to check on your own script.

References and control

Kling takes up to 15 reference assets in total; the caps are 10 images, 5 videos and 7 elements, 3 of which can be video elements (user guide, checked November 5, 2026). Seedance takes up to 50: 30 images, 10 videos and 10 audio clips (BytePlus ModelArk's Seedance 2.5 page, checked November 5, 2026). Both cap reference video at 30 seconds in total (both checked November 5, 2026).

BytePlus says Seedance 2.5 and 2.0 “do not support directly uploading reference images or videos that contain real human faces”; model outputs and authorised digital characters are the workaround (create-task page, checked November 5, 2026). Kling's pages carry no equivalent restriction, which is not the same as permission: ask Kling before uploading a face.

Kling's user guide says multi-shot is on by default and storyboards can be used as references; it also supports first frames, last frames and up to 10 keyframes at any timeline position (checked November 5, 2026). Flash “does not currently support start-and-last frames or multiple keyframes,” according to the same guide. Seedance plans connected shots inside one generation, and its API exposes no storyboard or shot-list field for 2.5 (ByteDance Seed launch post and BytePlus docs, checked November 5, 2026). Kling describes push-ins, pull-outs, pans, tracking and orbit shots as prompt-driven moves (user guide, checked November 5, 2026). Seedance's camera_fixed parameter is listed only for 1.5 pro, 1.0 pro and 1.0 pro fast, so moves on 2.5 come from the prompt (BytePlus create-task page, checked November 5, 2026).

In the Hacker News thread on the Seedance 2.5 launch, the commenter zmmmmm wrote on August 1, 2026: “The problem with these tools is the lack of fine grained control means there is no room for you to express your individual creative input.”

Resolution and output

Kling lists 720p, 1080p and 4K, and says 10-bit HDR is coming soon (user guide and product page, checked November 5, 2026). Its own samples are 1080p, so 1080p output is live. Seedance 2.5 tops out at 1080p: 480p, 720p and 1080p, with 720p the default, and 1080p output is 10-bit H.265/HEVC (BytePlus create-task page, checked November 5, 2026). 4K belongs to Seedance 2.0.

Kling publishes no frame rate for 4.0 on its launch post, 3.0-vs-4.0 post, user guide, product page or news post (all checked November 5, 2026). BytePlus lists 24 fps for Seedance 2.5 (checked November 5, 2026).

All six files are H.264 at 24 fps and 8-bit colour. Kling's samples are 1920×1088 (K-04), 1920×1080 (K-05) and 1912×1080 (K-13), with AAC audio at 44.1 kHz and two channels, running 15.04, 7.04 and 15.04 seconds. Ours are 1280×720 with AAC at 32 kHz and two channels, running 10.08, 7.07 and 15.07 seconds.

API access and price

Kling's @Kling_ai account posted on November 4, 2026 that “Kling 4.0 Flash is now available to everyone on the Kling AI website and via API” (checked November 5, 2026). That is the only 4.0 API statement we could retrieve.

Kling's developer pricing page lists Kling 3.0 Turbo, 3.0 and 3.0 Omni for video and no 4.0 row (checked November 5, 2026). For context, the page prices Kling 3.0 at 0.8 Units ($0.112) per second at 1080p without audio, 1.2 Units ($0.168) per second with native audio, and 3.0 Units ($0.42) per second at 4K. Kling's developer docs would not render their model list, so no 4.0 model ID or endpoint could be read (checked November 5, 2026). Kling has not published a 4.0 API price.

BytePlus ModelArk's create-task page says “Dreamina Seedance 2.5 is now fully available” and invites you to call the API (checked November 5, 2026). The July 31 launch post's “coming soon” line is out of date. Prices are per token. Without video input, the rate is $10.70 per million tokens at 480p and 720p and $11.70 at 1080p; with video input, $6.40 and $7.00 (BytePlus model pricing page, checked November 5, 2026). BytePlus's own 5-second 16:9 examples:

The per-second column is our arithmetic from those per-clip examples. For longer clips, BytePlus bills by a formula: (input video duration + output video duration) × width × height × frame rate ÷ 1024 tokens.

On OmniaKey

Seedance 2.5 is on OmniaKey as dreamina-seedance-2-5-260628 for text, image and reference to video; Kling 4.0 is not, and Kling 3.0 is.

• The model takes 480P, 720P or 1080P and 4–30 seconds. Use the full ID: the short seedance-2-5 alias is not served and answers 503 no_available_channel.
• Audio renders by default; send parameters.generate_audio: false for a silent clip.
• First frames and reference images go in input.media[] with a type of first_frame or reference_image, as inline data URIs. image_to_video on 2.5 needs parameters.ratio: "adaptive".

curl --fail-with-body https://api.omniakey.com/v1/media/tasks \
  -H "Authorization: Bearer your-omniakey-api-key" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: uk-reunion-001" \
  -d '{
    "model": "dreamina-seedance-2-5-260628",
    "type": "video",
    "operation": "text_to_video",
    "input": {"prompt": "A single continuous 7-second shot set in the UK. At dusk, two friends who have not seen each other in a long time meet at the corner of a quiet street and share a warm embrace. Include natural footsteps, street ambience, background music, and dialogue in English."},
    "parameters": {"resolution": "720P", "ratio": "16:9", "duration": 7, "generate_audio": true}
  }'

1. Submit the job and keep the task ID from the 202 response.
2. Poll GET /v1/media/tasks/{id} until the status is succeeded.
3. Download the clip from the short-lived signed URL in assets[0].url.

Our three runs took 383.8 to 875.1 seconds, and the video API docs name 2.5 the slowest video model OmniaKey lists.

Rates are on the Seedance 2.5 model page and the Kling 3.0 model page; every parameter is in the video API docs; to try models without code, open the AI Video Generator.

Which should you use?

• Several languages including French or Hindi: Kling 4.0. It lists both; Seedance's 11 on ModelArk do not include them.
• A silent clip or your own soundtrack: Seedance 2.5, with generate_audio: false. Kling's audio and lip sync are on by default with no separate toggles.
• Stereo sound: Kling 4.0, which renders two-channel stereo; Seedance audio is mono.
• Shot-by-shot control: full Kling 4.0, with up to 10 keyframes and storyboards as references (Flash has no multiple keyframes); Seedance 2.5's API has no storyboard or shot-list field.
• Many reference files: Seedance 2.5, up to 50 against Kling's 15, though both cap reference video at 30 seconds total.
• Real-person references: check Kling first, because BytePlus does not accept uploaded real faces on Seedance 2.5 and Kling's pages list no equivalent rule.
• 4K on the spec sheet: Kling 4.0 lists 4K, with HDR marked coming soon; Seedance 2.5 stops at 1080p, with 4K in 2.0.
• A story past 30 seconds: Seedance 2.5 today, because its extend task is described in the API docs; Kling's two-minute extension is marked coming soon in the user guide.
• API access with published prices today: Seedance 2.5 on BytePlus ModelArk; Kling has announced 4.0 Flash on the API and publishes no 4.0 price.

For the full picture on each model, read our Kling 4.0 review, our Seedance 2.5 review and Kling 3.0 vs Seedance 2.5.

Frequently asked questions

Is Kling 4.0 better than Seedance 2.5?

Neither wins across every job: Kling 4.0 fits stereo sound, French or Hindi dialogue, a 4K line on its spec sheet, and keyframe and storyboard control; Seedance 2.5 fits silent output, up to 50 reference files, and an API with published token prices. The choice follows the job, and our three single runs are too few to rank overall quality.

Can you turn off audio in Kling 4.0?

No. Kling's own FAQ says audio-visual synchronization and Smart Storyboard are enabled by default and have no separate toggles. Seedance 2.5 returns a silent video when you send generate_audio: false.

How long can Kling 4.0 and Seedance 2.5 videos be?

Kling 4.0 makes 3–30 seconds in one pass, or 3–20 seconds on Flash, and Seedance 2.5 makes 4–30 seconds or lets the model choose with -1. Kling's two-minute extension is announced; Seedance's extend task is described in its API docs with no published cap.

Does Kling 4.0 have an API?

Kling 4.0 Flash is available via API, according to Kling's November 4 post. Kling publishes no 4.0 model ID, endpoint or API price, and its developer pricing page lists only the 3.0 family.

How much does Seedance 2.5 cost per second?

BytePlus's own 5-second examples work out to $0.103 per second at 480p, $0.231 at 720p and $0.569 at 1080p for input without video. Those figures come from its per-clip prices, and longer clips follow its token formula.

Which languages can Kling 4.0 and Seedance 2.5 speak?

Kling 4.0 lists nine dialogue languages, including French and Hindi. Seedance 2.5 lists 11 on ModelArk, which does not include French or Hindi; BytePlus's Lumina page claims both, so check the language list for the access path you use.

Sources checked

• Kling 4.0 launch post — posted September 30, 2026.
• Kling 4.0 vs Kling 3.0 — posted September 30, 2026.
• Kling 4.0 user guide — updated November 4, 2026.
• Kling 4.0 product page — checked November 5, 2026.
• Kling news post — posted October 26, 2026.
• Kling developer pricing — checked November 5, 2026.
• Kling developer docs — checked November 5, 2026.
• Kling @Kling_ai post — posted November 4, 2026.
• ByteDance Seed: Seedance 2.5 launch post — posted July 31, 2026.
• Seedance 2.5 product page — checked November 5, 2026.
• BytePlus ModelArk: create a video generation task — checked November 5, 2026.
• BytePlus ModelArk: Seedance 2.5 — checked November 5, 2026.
• BytePlus ModelArk: model pricing — checked November 5, 2026.
• BytePlus Lumina: Seedance 2.5 — checked November 5, 2026.
• Hacker News comment by zmmmmm — posted August 1, 2026.

Tested and checked November 5, 2026.