# DaVinci Resolve AddTransition API — effect skill for transitions

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Resolve 21.1 added TimelineItem.AddTransition; earlier versions cannot add transitions by script.

- **Type:** [Effect](https://varg.ai/how-to/effects.md) · [Transitions](https://varg.ai/how-to/browse/skills/transitions.md)
- **Slug:** `resolve-add-transition`
- **Status:** live
- **Publisher:** varg (varg, verified)
- **License:** MIT
- **Source:** https://github.com/vargHQ/skills/blob/main/varg-video-edit-library/references/transitions.md#resolve-add-transition
- **Works in:** Claude Code, Claude.ai, Codex, Cursor, OpenClaw, Gemini CLI, Any MCP client, varg Studio
- **Requires:** Python
- **Cost:** Free — the take renders locally; generated footage, if any, bills by the model

## What it does

Native Resolve transitions (Cross Dissolve, Fusion, OFX, audio) on a timeline built by script.

**When:** Pipelines that assemble timelines in Resolve via Python/Lua and want dissolves without manual work.

**Watch out:** Relying on it before 21.1; on older versions build the timeline as OTIO/FCP7 XML with transitions and import it.

**Timing:** duration in frames (auto-calculated when omitted); needs handles on both clips

**Also called:** Resolve scripting, TimelineItem.AddTransition, DaVinciResolveScript, Resolve API transitions

### In Python

Resolve scripting (Python 3, run inside Resolve or with the scripting env):
```python
import DaVinciResolveScript as dvr
resolve = dvr.scriptapp('Resolve')
timeline = resolve.GetProjectManager().GetCurrentProject().GetCurrentTimeline()
items = timeline.GetItemListInTrack('video', 1)
# Resolve 21.1+: attach a dissolve to the end of the first clip, centred on the cut
items[0].AddTransition({'type': 'Cross Dissolve', 'category': 'simple', 'position': 'end', 'alignment': 'center', 'duration': 15})
```
TransitionOptions: `type` (name, e.g. 'Cross Dissolve'), `category` ('simple' | 'fusion' | 'ofx' | 'audio'), `position` ('start' | 'end'), `alignment` ('left' | 'center' | 'right'), `duration` (frames). Returns the transition TimelineItem or None. Older versions: `MediaPool.ImportTimelineFromFile('edit.otio' or FCP7 XML)`; `Timeline.Export(path, resolve.EXPORT_OTIO)` writes OTIO back out (FCPXML 1.3–1.7 export is unsupported since 18.1; 1.8–1.10 remain).

### Where this comes from

- [DaVinci Resolve scripting API 21.1 README mirror](https://github.com/WheheoHu/bmd_doc/tree/main/_README_API/21_1_1)
- [OpenTimelineIO: timeline structure (Transition)](https://opentimelineio.readthedocs.io/en/latest/tutorials/otio-timeline-structure.html)

## Use when

- Pipelines that assemble timelines in Resolve via Python/Lua and want dissolves without manual work.

## Not for

- Relying on it before 21.1; on older versions build the timeline as OTIO/FCP7 XML with transitions and import it.

## Install

- Claude Code: `claude plugin marketplace add vargHQ/skills && claude plugin install varg@varg`
- Codex: `npx skills add vargHQ/skills --skill varg-video-edit-library -a codex -y`
- Cursor: `npx skills add vargHQ/skills --skill varg-video-edit-library -a cursor -y`

## Example output

https://s3.varg.ai/how-to/previews/ed4c06dba941/take-resolve-add-transition.mp4 — Cross Dissolve between two shots, with the timeline strip of the edit. Footage: Charge (2022), Blender Studio | studio.blender.org, CC BY 4.0; Spring (2019), Andy Goralczyk / Blender Foundation (Blender Studio) | studio.blender.org, CC BY 4.0. (credit: Rendered by varg · Charge (2022) + Spring (2019))

## More transitions skills

- [editly](https://varg.ai/how-to/skills/editly.md): Declarative JSON5 video editing CLI/API: clips, titles, transitions, audio mixing, rendered with ffmpeg.
- [Mix (Cross Dissolve)](https://varg.ai/how-to/skills/mix-dissolve.md): The two shots blend through each other. The quietest transition: "time passes" or "this continues".
- [Dip to Black](https://varg.ai/how-to/skills/black-fade.md): A fades to black, then B fades up. Marks the end of a section or a bigger jump in time.
- [White Flash](https://varg.ai/how-to/skills/white-flash.md): The frame blows out to white for a moment and opens on the next shot. Energy, memory or a camera snap.
- [Pull In (Zoom In)](https://varg.ai/how-to/skills/pull-in-zoom.md): The camera rushes into shot A and lands, still moving forward, in shot B. The signature short-form transition.
- [Pull Out (Zoom Out)](https://varg.ai/how-to/skills/pull-out-zoom.md): The camera jerks backwards out of shot A and keeps pulling back as shot B settles in.