Command · Set Transition

transition.set

Changes a transition: its effect, parameters, its length on either side of the cut ("before", "after"), a new total "duration" placed by its alignment, or the alignment itself (which re-splits it; "custom" with "offset" puts the cut that far in).

• v1
• Capability EditSequence
• Tool transition_set

Request

{
  "command": "transition.set",
  "params": {
    "duration": "00:00:01:00",
    "effect": "dipToBlack",
    "transition": 90
  }
}

Parameters

afterinteger | string

New length after the cut. Timecode in the sequence's rate ("00:01:02:03") or ticks.

alignment`center` | `startAtCut` | `endAtCut` | `custom`

Where the transition sits on a cut between two clips: centered (default), starting at the cut (the outgoing clip plays on), ending at it, or custom: the cut lies "offset" into it (by default where it is now). Stored on the transition: a new duration keeps it. Ignored for a one-sided transition at a clip end with no neighbour.

beforeinteger | string

New length before the cut. Timecode in the sequence's rate ("00:01:02:03") or ticks.

durationinteger | string

New total length, split by alignment. Timecode in the sequence's rate ("00:01:02:03") or ticks.

effect`crossDissolve` | `dipToBlack` | `dipToWhite` | `wipe` | `constantPower` | `constantGain`

New transition effect.

fit`exact` | `availableHandles`

When the media lacks frames beyond the cut: "exact" fails with how much there is, "availableHandles" shortens the transition to fit (default).

offsetinteger | string

With alignment "custom": how much of the transition lies before the cut. Timecode in the sequence's rate ("00:01:02:03") or ticks.

paramsobject

New constant parameters (replace all).

sequenceinteger (1..)

Sequence id; only needed when the project has several.

transitioninteger (1..)Required

Transition id (sequence.summary and clip.details list them).

Discussion

Run it with wabcut-cli cmd <project> --json, from an MCP client as transition_set, or from an extension. See Edit commands for requests, references and results.