# GL Transitions via editly or FFmpeg — effect skill for transitions

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Run any of the ~125 GLSL gl-transitions between clips: editly (no custom build) or a patched FFmpeg.

- **Type:** [Effect](https://varg.ai/how-to/effects.md) · [Transitions](https://varg.ai/how-to/browse/skills/transitions.md)
- **Slug:** `gl-transitions-ffmpeg-editly`
- **Status:** live
- **Publisher:** gre · GL Transitions (community)
- **License:** MIT
- **Source:** https://github.com/gl-transitions/gl-transitions/blob/master/transitions/Cube.glsl
- **Works in:** Claude Code, Claude.ai, Codex, Cursor, OpenClaw, Gemini CLI, Any MCP client, varg Studio
- **Requires:** ffmpeg
- **Cost:** Free — the take renders locally; generated footage, if any, bills by the model

## What it does

Built on [Cube](https://github.com/gl-transitions/gl-transitions/blob/master/transitions/Cube.glsl) by gre (gl-transitions), MIT. The write-up and recipes below are varg's.

Cube, page curl, doorway, morph, burn, glitch and other shader transitions xfade cannot do.

**When:** Server-side batch renders that need 3D or organic transitions without a browser.

**Watch out:** Mixing name sets: editly depends on gl-transitions 1.x (`crosswarp`, `cube`), the 2.0 catalog uses PascalCase (`CrossWarp`, `Cube`).

**Timing:** 0.5–1.0 s typical

**Also called:** gltransition filter, ffmpeg-gl-transition, editly, ffmpeg-concat, GLSL transitions

### In FFmpeg

FFmpeg itself has no GL transitions. Option 1, editly (Node, standard ffmpeg):
```js
import editly from 'editly';
await editly({
  outPath: 'out.mp4',
  defaults: { transition: { name: 'crosswarp', duration: 0.5 } },
  clips: [
    { layers: [{ type: 'video', path: 'a.mp4' }] },
    { transition: { name: 'cube', duration: 1, params: { persp: 0.5 } }, layers: [{ type: 'video', path: 'b.mp4' }] },
    { layers: [{ type: 'video', path: 'c.mp4' }] },
  ],
});
```
`transition` on a clip applies between it and the next; also `random`, `dummy`, `directional-left|right|up|down`.
Option 2, the third-party `gltransition` filter (rebuild FFmpeg with the patch, needs an OpenGL/EGL context):
```bash
ffmpeg -i a.mp4 -i b.mp4 -filter_complex "gltransition=duration=1:offset=2:source=CrossWarp.glsl" out.mp4
```
The filter sets only `progress` and `ratio`; bake parameter uniforms into constants, and transitions that need extra textures do not work.

### Ready-made components

- [Cube](https://skills.varg.ai/component/glt.cube/) (gl-transitions): npm install gl-transitions
- [CrossZoom](https://skills.varg.ai/component/glt.cross-zoom/) (gl-transitions): npm install gl-transitions
- [DirectionalWarp](https://skills.varg.ai/component/glt.directional-warp/) (gl-transitions): npm install gl-transitions
- [Doorway](https://skills.varg.ai/component/glt.doorway/) (gl-transitions): npm install gl-transitions
- [InvertedPageCurl](https://skills.varg.ai/component/glt.inverted-page-curl/) (gl-transitions): npm install gl-transitions
- [FilmBurn](https://skills.varg.ai/component/glt.film-burn/) (gl-transitions): npm install gl-transitions

### Where this comes from

- [editly](https://github.com/mifi/editly)
- [ffmpeg-gl-transition (third-party filter)](https://github.com/transitive-bullshit/ffmpeg-gl-transition)
- [GL Transitions gallery](https://gl-transitions.com)
- [gl-transitions 2.0 changelog (renames)](https://github.com/gl-transitions/gl-transitions/blob/master/packages/gl-transitions/CHANGELOG.md)

## Use when

- Server-side batch renders that need 3D or organic transitions without a browser.

## Not for

- Mixing name sets: editly depends on gl-transitions 1.x (`crosswarp`, `cube`), the 2.0 catalog uses PascalCase (`CrossWarp`, `Cube`).

## 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/c62b6d8fdbea/lib-gl-transitions-cube.mp4 — Preview of the Cube component that builds this take (credit: Rendered by varg from the library’s own code (GL Transitions · rendered by varg), https://gl-transitions.com/editor/Cube)

## 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.

## Run the generation on varg

varg is one API key for the models these skills drive — Seedance 2.5, Kling 4, Veo 3.1, Wan 3, Nano Banana 2.1, GPT Image 2.5, ElevenLabs v4 and 200+ more — billed in credits, with a cost estimate before anything runs.

- Claude Code: `claude plugin marketplace add vargHQ/skills && claude plugin install varg@varg` (skill + hosted MCP)
- Codex, Cursor, Gemini CLI, OpenClaw: `npx skills add vargHQ/skills --skill varg-ai -a <agent> -y`
- Grok and any agent that reads SKILL.md: `npx skills add vargHQ/skills --skill varg-ai`, or point it at the skill's SKILL.md
- Claude.ai, ChatGPT, any MCP client: connect `https://mcp.varg.ai/mcp`
- API key: https://varg.ai/dashboard/api · Model specs: https://varg.ai/models/llms.txt