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A video node shows only the handles its selected model can use, so the ports change when you switch models or variants. Which handle you wire to decides how the upstream asset is used.

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Compare videos on the canvas

Click Play on each video you want to compare. Videos keep playing when you start another clip or select a different node. You can pause or scrub each clip independently, including uploaded videos and stitch previews. Videos start muted. Click Enable sound on a clip to hear it; the other clips keep playing silently. While sound is enabled, starting another clip transfers sound to that clip. Opening fullscreen mutes the canvas previews behind it.

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Duration

Set Duration in the node toolbar or the right-hand Generation settings panel. Both controls show the duration used for generation. When you have not selected a duration, the model’s configured default applies; otherwise it starts at the shortest supported duration. Seedance 2.5 starts at 4 seconds. Choosing a longer duration in either control updates the next generation. Models driven by an input clip or audio track use that input’s duration instead. For Seedance 2.5 with exactly one video input and no image or audio references, Duration shows Auto and cannot be edited. The model chooses the output length. The credit quote and upfront charge use the source clip’s duration, rounded up to whole seconds, plus the input-video charge. If the source duration is unavailable, the quote uses the model’s default duration. Adding another reference restores the manual duration control.

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Input video limits

Duration controls the generated output. Input videos have separate limits that depend on the selected model and mode. For example, Wan 3.0 can generate up to 30 seconds, but accepts at most 15 seconds of reference video in total. If an input clip is too long or too short, the error names the model, its input-duration limit, and your clip’s length. Trim the connected input video or use a longer clip as directed; changing the output Duration does not change the input limit. Video-count errors also tell you how many clips the model accepts. When you run several nodes with Run selected, every connected clip is checked before anything runs. If a clip is too long or too short for its model, nothing runs and the node shows the model’s limit. Trim the clip with its Trim tool, or connect a different clip, then run again.

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Input handles

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Pairing rules

  • A last frame only works alongside a starting frame. A last-frame-only run is rejected with “Starting frame and last frame must be used together.”
  • Frames and reference images are mutually exclusive unless the model accepts both — for example Kling 3.0 Omni’s reference-to-video variant.
  • Each model caps how many image and reference-image inputs it accepts. Wiring more than the cap is rejected.

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Output handles

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Shot chaining

To produce a multi-shot sequence:
  1. Create your first video node and run it.
  2. Add a second video node downstream.
  3. Drag from the first node’s Last frame output to the second node’s Starting frame input.
  4. Prompt the second node with how the action should continue.
Each shot picks up exactly from the previous shot’s last frame, so motion and composition stay consistent. To carry a character or style across shots instead of an exact frame, wire the same image into every node’s Reference image handle.

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Playback of oversized uploads

Beta — this feature is rolling out gradually. Reach out to support if you’d like access.
Uploaded videos wider or taller than 4096 pixels are harder for phones and many laptops to decode, so playback can stutter. For those uploads, Melius prepares a processed H.264 MP4 that fits within 3840 × 2160 (or 2160 × 3840 for portrait video) and plays it in the canvas fullscreen viewer, the Files viewer, public asset links and files opened from a public folder link. The original file is kept unchanged. A freshly uploaded oversized video shows a loading spinner labelled Preparing until the copy is ready; the viewer updates on its own. If preparation fails, the viewer plays the original file instead. Smaller uploads and generated videos play as before.

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Download oversized uploads

Beta — this feature is rolling out gradually. Reach out to support if you’d like access.
For uploaded videos wider or taller than 4096 pixels, Download hands back the original file until the processed copy is ready. Once it is, Download selects the Optimized MP4 by default: an H.264 file that keeps the aspect ratio, fits within 3840 × 2160 (or 2160 × 3840 for portrait video), runs at up to 30 frames per second and carries stereo AAC audio, so it plays smoothly on more devices. Open Download options beside the button, or the Download submenu in a file’s menu, to pick Original whenever you need the source’s full resolution, frame rate, colour and audio for editing. The original is always available and never changes. The menu shows each file’s dimensions and size, and marks the Optimized row Preparing while the copy is still being made. Choosing Optimized before it has been prepared, or after a failed preparation, starts the preparation and downloads the file when it is ready; keep the page open. This choice appears in Files, canvas viewers, Playground, Cast, public asset links and public folder links. Smaller videos keep their existing download action, and bulk ZIP downloads plus API, CLI and MCP downloads always include original files.
Last modified on October 6, 2026