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Authors and ModelsKling AI

Kling 4.0 Flash

Kling 4.0 Flash
Kling AI · Video Generation
POST /v1/videos/generations

The faster, lower-cost Kling 4.0: 3 to 20 second clips at 720p with native audio from text, a first frame, reference images and videos, or a video to edit.

At a glance

FieldValue
Model idkling-4-0-flash
Model release date2026-11-04
Input modalitiesText, Image, Video
Output modalitiesVideo
Context window-
Weight precision-
Featuresvideo_generation, text_to_video, image_to_video, audio, editing
Native inferenceNo
NewYes
Supported endpointsPOST /v1/videos/generations
Alternate model idskling-4.0-flash, kling/kling-4-0-flash

Pricing

ChargeSpecRate
Standard 720pper second$0.094
Video input 720pper second of input plus output, at least twice the output$0.063

Example request

curl https://api.empiriolabs.ai/v1/videos/generations \
  -H 'Authorization: Bearer $EMPIRIOLABS_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"model": "kling-4-0-flash", "prompt": "sunrise over the ocean", "duration": 6}'

Parameters

ParameterTypeRequiredDefaultDescription
promptstringyes-Scene description, up to 26,000 English or 11,000 non-English characters. Refer to reference images as @image_1, @image_2 and videos as @video_1 in the order they are supplied.
resolutionenumno"720p"Output resolution. · Allowed: 720p
aspect_ratioenumno"16:9"Output aspect ratio for text-to-video and references. A first frame on its own, or a video to edit, sets the aspect ratio instead. · Allowed: 16:9, 9:16, 1:1, 21:9
durationnumberno5Clip length in seconds, whole numbers only. A video edit keeps the length of the video it edits. · Range: 3 – 20
imagestringno-First frame image URL. The video starts on this image.
reference_imagesstringno-Reference image URLs for characters, objects, scenes or style, as a list or comma-separated. Up to 10 images in total.
videostringno-Video URL to edit, 3 to 20 seconds. The result keeps its length, and bills at the video input rate.
reference_videosstringno-Reference video URLs for motion, camera work or style, 3 to 20 seconds each and 20 seconds of video in total, as a list or comma-separated. Up to 5 videos in total. Bills at the video input rate.

Notes

Generates 3 to 20 second clips at 24 fps in 720p, each with a native stereo audio track.

Inputs

  • Text to video: prompt only.
  • First frame (image): the video starts on this image and follows its aspect ratio.
  • Reference images (reference_images): characters, objects, scenes or style to use. A first frame can be sent with them.
  • Reference videos (reference_videos): motion, camera work or style to follow, 3 to 20 seconds each.
  • Video edit (video): a video to edit, 3 to 20 seconds. The result keeps its length.
  • Up to 10 images and 5 videos per request, with at most 20 seconds of video in total. In the prompt, refer to reference images as @image_1, @image_2 and to videos as @video_1, @video_2 (the video to edit first).
  • Last and middle frames and 1080p are available on Kling 4.0.

In the Playground

One attached image is the first frame, and two or more are references. The first attached video is the one edited; any others are references.

Media limits

  • Images: JPG or PNG, at least 300 px, aspect ratio between 2:5 and 5:2, up to 30 MB.
  • Videos: MP4 or MOV, 3 to 20 seconds, 700 to 4553 px per side, 24 to 60 fps, up to 300 MB.

Billing

  • Without a video input: billed per second of the generated clip.
  • With a video input (a video to edit or a reference video): billed at the video input rate on twice the length of the generated clip, or on the input plus the output when the input is longer.

Machine-readable schema: GET https://api.empiriolabs.ai/v1/models/kling-4-0-flash.