Extend Video

The Extend Video node continues an existing video with new footage that follows your prompt. You connect a clip, describe what happens next, and the node returns a longer video. Use it to let a shot run on, to add a new action at the end of a scene, or, with LTX 2.3 Pro, to add a lead-in before the clip starts.

Extending a video is not available on free credits, on any model. It opens after the first purchase. See Video on free credits.

When to use it

• A generated clip ends too early, and the shot should keep going.
• A scene needs a new action or a change of direction at its end.
• You need a longer continuous shot than one generation gives. Chain several Extend Video nodes, one after the other.
• A hero clip needs an establishing moment in front of it. Use LTX 2.3 Pro with Extend Mode set to Start (prepend backwards).

Quick start

Inputs

The output, Video, is the extended clip. It can feed any video input, including another Extend Video node.

Settings

Models

Extend Video runs six extend models: Seedance 2.5, Seedance 2.0, Kling 4, LTX 2.3 Pro, VEO Extend and Runway Extend. Click a model below for its settings and credit prices. The Seedance and Kling 4 prices are in Credits.

Which model to choose

• Seedance 2.5 and Seedance 2.0 continue any clip, sound included, and join the two parts into one continuous video. Use them for uploads and for clips from other models. Seedance 2.5 adds the longest footage per run.
• Kling 4 continues any clip by 3 to 30 seconds, always with sound. It takes no reference images.
• LTX 2.3 Pro is the only model that can add footage before a clip. Only LTX 2.3 Pro extends; LTX 2.3 Fast does not.
• VEO Extend continues a VEO clip. Use Fast while you iterate and Quality for the final render.
• Runway Extend continues a Runway clip.

A saved workflow, app or API call that names the earlier Seedance id, seedance-2-extend, keeps working. It now runs, and is priced, as Seedance 2.5. A length under 4 seconds on that id runs as 4 seconds. Choose Seedance 2.0 to keep the earlier model.

What a run refuses

A run is refused before any credits are reserved in these cases:

• The length is outside the model's window. Seedance 2.5 adds 4 to 30 seconds, Seedance 2.0 adds 4 to 15, Kling 4 adds 3 to 30 and LTX 2.3 Pro adds 1 to 20. VEO Extend and Runway Extend choose their own length.
• The resolution is one the model does not make. Kling 4 makes 720p or 1080p, so 480p sent through the API is refused. A saved node with 480p on Kling 4 runs at 720p.
• The source is too short to continue (video_too_short, Seedance and Kling 4). Both continue from the last seconds of the source. The source must be at least 1.8 seconds long on Seedance and 2 seconds on Kling 4.

How Seedance and Kling 4 join the clips

Seedance 2.5, Seedance 2.0 and Kling 4 watch the end of the source clip and generate only what happens next, soundtrack included. Seedance watches the last 2 seconds, and Kling 4 the last 3 seconds, or all of a shorter source. Nodaro then joins the source and the extension into one clip:

1. The node compares the last 8 frames of the source with the first 8 frames of the extension.
2. The source ends on the frame that best matches the extension, and the extension starts right after its near-identical twin. The shared moment plays exactly once, and the motion continues through the cut.
3. If no pair of frames is close enough, the join uses fixed trims instead: 4 frames from the end of the source and 3 from the start of the extension.

The join is a hard cut with a short audio blend. The extension always matches the aspect ratio of the source, and it is scaled and cropped at the center to the source's frame.

What you get back. The extended video keeps the source's size and frame rate, whichever resolution you choose. It is encoded once as an H.264 MP4 with AAC sound. An H.264 source keeps its own bitrate, and a source in another codec is encoded at a high constant quality. A 10-bit, HDR or full-range source comes back as 8-bit, standard dynamic range and standard range. A run with the free-tier watermark is encoded once more to add it, so its picture quality is lower.

Credits

The price depends on the model:

• LTX 2.3 Pro reserves 44 credits for each second you add. The seconds are whole numbers from 1 to 20, and 6 when Duration (seconds to add) is empty, which is the model's own default. The run is then charged what the render actually costs, never more than the reservation, and the rest is refunded. The node's Run button and the workflow estimate show the reservation before you run. A workflow run and a call from the API are priced the same way.
• Seedance 2.5 and Seedance 2.0 are priced by the exact seconds added and the resolution. Every whole second has its own price at each resolution, and there are no tiers. Seedance 2.5 costs more than Seedance 2.0 for the same length. With no length set, the run adds 8 seconds at 720p.
• Kling 4 is priced the same way: every whole second from 3 to 30 has its own price at 720p and 1080p. With no length set, the run adds 5 seconds at 720p. Sound is included.
• VEO Extend and Runway Extend have a fixed price per run. VEO Extend costs more with Quality than with Fast.

The node's Run button and the workflow estimate show the exact price of any length before you run. From the API, GET /v1/credits/model-cost returns it for the identifier seedance-2-5-extend:<seconds>s:<resolution>, seedance-2-0-extend:<seconds>s:<resolution> or kling-4-extend:<seconds>s:<resolution>, for example seedance-2-5-extend:8s:720p. Reference images, available from the API, add no credits.

Tips

• Describe the next moment, not the scene. Plain action language works best, for example the ball keeps rolling until it hits a cup. For Start mode, describe what happens before the clip.
• Chain nodes for long shots. Each LTX 2.3 Pro run adds up to 20 seconds, and each Seedance 2.5 or Kling 4 run up to 30 seconds. Two chained runs add up to 40 or 60 seconds. Wire the output of one Extend Video node into the Video input of the next.
• Match the resolution. With Seedance and Kling 4, choose the source video's resolution for the cleanest seam. The new footage is scaled to the source's size, so a lower resolution looks softer after the join.
• Fix a moment inside the clip instead. To change a few seconds in the middle of a video, use Retake Video or Edit Video Pro.
• Join separate clips without a jump. To join clips that continue each other, use the Seamless Join (One-Shot) preset of Combine Videos.

From the API

POST /v1/extend-video and the MCP extend_video tool also accept reference images for Seedance 2.5 and Seedance 2.0. References keep a person, a product or an object the same in the extension, instead of relying on a description.

• referenceImageUrls is a list of image URLs. Mention each one in the prompt as @image_1, @image_2 and so on, in list order.
• connectedReferences takes the same structured references as POST /v1/generate-video.

Up to 8 reference images attach. The model holds one more image, the last frame of the source clip, which anchors the continuation. Mention every reference in the prompt, so the model knows what each one is for. Reference images work only with the Seedance models: another model, Kling 4 included, returns an error instead of ignoring them. See Run a single node and the MCP tools.