Remotion Composition

Generates composition structure documents that define how scenes are ordered, timed, and transitioned in a Remotion video. This skill focuses exclusively on Sequence layout and timing orchestration.

What This Skill Does

Generates composition structure for:

1. Sequence layout — Ordering and positioning of scene Sequences
2. Timing calculations — Start frames, end frames, duration for each scene
3. Scene transitions — Overlap and crossfade timing between scenes
4. Duration mapping — Converting seconds to frames for all scenes
5. Timing constants — Structured timing object for constants.ts

Scope Boundaries

IN SCOPE:

• Sequence component organization
• Frame calculations for scene timing
• Scene overlap and transition timing
• Duration constant generation
• Scene ordering logic

OUT OF SCOPE:

• Scene component implementation (use /remotion-component-gen)
• Animation parameters (use /remotion-animation)
• Visual styling (colors, layouts)
• Asset management (use /remotion-asset-coordinator)

Input/Output Formats

Input Format: Scene List with Durations

Accepts scene timing specifications:

Natural Language:

Scene 1 (Intro): 0-5 seconds
Scene 2 (Features): 5-15 seconds
Scene 3 (Demo): 15-25 seconds
Scene 4 (CTA): 25-30 seconds

Structured Format:

## Scene Timing

**Total Duration:** 30 seconds
**Frame Rate:** 30 fps
**Total Frames:** 900

**Scenes:**
1. Scene 1 - Intro: 5 seconds (0s - 5s)
2. Scene 2 - Features: 10 seconds (5s - 15s)
3. Scene 3 - Demo: 10 seconds (15s - 25s)
4. Scene 4 - CTA: 5 seconds (25s - 30s)

**Transitions:**
- Fade transition between scenes: 0.5 seconds (15 frames)

Output Format: COMPOSITION_STRUCTURE.md

Generates composition structure document:

# Composition Structure: ProductDemo

## Status
✅ Sequence layout defined
✅ Timing calculations complete
⏳ Ready for scene implementation

## Composition Overview

**Total Duration:** 30 seconds (900 frames @ 30fps)
**Scenes:** 4
**Transitions:** Crossfade (15 frames)

## Scene Timing Constants

```typescript
const FPS = 30;

export const SCENE_TIMING = {
  intro: {
    start: 0,
    end: 150,
    duration: 150,
    // 0s - 5s
  },
  features: {
    start: 150,
    end: 450,
    duration: 300,
    // 5s - 15s
  },
  demo: {
    start: 450,
    end: 750,
    duration: 300,
    // 15s - 25s
  },
  cta: {
    start: 750,
    end: 900,
    duration: 150,
    // 25s - 30s
  },
} as const;

// Transition timing
export const TRANSITIONS = {
  crossfadeDuration: 15, // frames (0.5 seconds)
} as const;

Composition Layout

Main composition with Sequence structure:

import { AbsoluteFill, Sequence } from "remotion";
import { SCENE_TIMING } from "./constants";
import { Scene1Intro } from "./scenes/Scene1Intro";
import { Scene2Features } from "./scenes/Scene2Features";
import { Scene3Demo } from "./scenes/Scene3Demo";
import { Scene4CTA } from "./scenes/Scene4CTA";

export function ProductDemo() {
  return (
    <AbsoluteFill>
      {/* Scene 1: Intro (0s - 5s) */}
      <Sequence
        from={SCENE_TIMING.intro.start}
        durationInFrames={SCENE_TIMING.intro.duration}
      >
        <Scene1Intro />
      </Sequence>

      {/* Scene 2: Features (5s - 15s) */}
      <Sequence
        from={SCENE_TIMING.features.start}
        durationInFrames={SCENE_TIMING.features.duration}
      >
        <Scene2Features />
      </Sequence>

      {/* Scene 3: Demo (15s - 25s) */}
      <Sequence
        from={SCENE_TIMING.demo.start}
        durationInFrames={SCENE_TIMING.demo.duration}
      >
        <Scene3Demo />
      </Sequence>

      {/* Scene 4: CTA (25s - 30s) */}
      <Sequence
        from={SCENE_TIMING.cta.start}
        durationInFrames={SCENE_TIMING.cta.duration}
      >
        <Scene4CTA />
      </Sequence>
    </AbsoluteFill>
  );
}

Scene Timing Breakdown

Total: 30 seconds (900 frames)

Timeline Visualization

Frame:     0        150       450       750       900
Time:      0s        5s        15s       25s       30s
           |---------|---------|---------|---------|
Scene:     |  Intro  | Features|   Demo  |   CTA   |
           |---------|---------|---------|---------|

Next Steps

1. Implement scenes via /remotion-component-gen
2. Add transitions if needed (crossfades, wipes)
3. Integrate constants into composition constants.ts
4. Test timing in Remotion preview
5. Adjust durations if scenes feel too fast/slow

Checklist

• Scene timing calculated
• Sequence layout defined
• Constants generated
• Timing constants structured
• Scene components implemented (next step)
• Transitions added (if needed)
• Timing tested in preview

## Composition Patterns

### Pattern 1: Sequential Scenes (No Overlap)

Standard sequential layout where scenes don't overlap:

```typescript
<Sequence from={0} durationInFrames={150}>
  <Scene1 />
</Sequence>

<Sequence from={150} durationInFrames={300}>
  <Scene2 />
</Sequence>

<Sequence from={450} durationInFrames={300}>
  <Scene3 />
</Sequence>

Pattern 2: Overlapping Scenes (Crossfade)

Scenes overlap for smooth transitions:

const CROSSFADE = 15; // frames

// Scene 1: Full duration
<Sequence from={0} durationInFrames={150}>
  <Scene1 />
</Sequence>

// Scene 2: Starts before Scene 1 ends
<Sequence from={150 - CROSSFADE} durationInFrames={300 + CROSSFADE}>
  <Scene2 />
</Sequence>

// Scene 3: Starts before Scene 2 ends
<Sequence from={450 - CROSSFADE} durationInFrames={300 + CROSSFADE}>
  <Scene3 />
</Sequence>

Pattern 3: Layered Composition

Background + foreground scenes running simultaneously:

{/* Background layer - runs full duration */}
<Sequence from={0} durationInFrames={900}>
  <BackgroundScene />
</Sequence>

{/* Foreground scenes - sequential */}
<Sequence from={0} durationInFrames={150}>
  <Scene1 />
</Sequence>

<Sequence from={150} durationInFrames={300}>
  <Scene2 />
</Sequence>

Pattern 4: Nested Sequences

Sub-scenes within main scenes:

<Sequence from={0} durationInFrames={300}>
  <AbsoluteFill>
    {/* Sub-scene 1 */}
    <Sequence from={0} durationInFrames={100}>
      <Intro />
    </Sequence>

    {/* Sub-scene 2 */}
    <Sequence from={100} durationInFrames={200}>
      <MainContent />
    </Sequence>
  </AbsoluteFill>
</Sequence>

Timing Calculation Helpers

Common frame calculations:

// Convert seconds to frames
const secondsToFrames = (seconds: number, fps: number = 30): number =>
  Math.round(seconds * fps);

// Calculate scene timing
interface SceneTiming {
  start: number;
  end: number;
  duration: number;
}

const calculateSceneTiming = (
  startSeconds: number,
  durationSeconds: number,
  fps: number = 30
): SceneTiming => {
  const start = secondsToFrames(startSeconds, fps);
  const duration = secondsToFrames(durationSeconds, fps);
  const end = start + duration;

  return { start, end, duration };
};

// Calculate crossfade overlap
const calculateCrossfade = (
  scene1Start: number,
  scene1Duration: number,
  crossfadeDuration: number
) => ({
  scene1: {
    from: scene1Start,
    durationInFrames: scene1Duration,
  },
  scene2: {
    from: scene1Start + scene1Duration - crossfadeDuration,
    durationInFrames: crossfadeDuration, // or more if scene is longer
  },
});

// Validate total duration
const validateDuration = (
  scenes: SceneTiming[],
  expectedTotal: number
): boolean => {
  const lastScene = scenes[scenes.length - 1];
  return lastScene.end === expectedTotal;
};

Scene Timing Generation

Automated timing generation