Teacher workspace remotion demo

.agents/skills/remotion-best-practices/SKILL.md

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+---
+name: remotion-best-practices
+description: Best practices for Remotion - Video creation in React
+metadata:
+  tags: remotion, video, react, animation, composition
+---
+
+## When to use
+
+Use this skills whenever you are dealing with Remotion code to obtain the domain-specific knowledge.
+
+## New project setup
+
+When in an empty folder or workspace with no existing Remotion project, scaffold one using:
+
+```bash
+npx create-video@latest --yes --blank --no-tailwind my-video
+```
+
+Replace `my-video` with a suitable project name.
+
+## Designing a video
+
+Animate properties using `useCurrentFrame()` and `interpolate()`. Use Easing to customize the timing of the animation.
+
+```tsx
+import { useCurrentFrame, Easing } from "remotion";
+
+export const FadeIn = () => {
+  const frame = useCurrentFrame();
+  const { fps } = useVideoConfig();
+
+  const opacity = interpolate(frame, [0, 2 * fps], [0, 1], {
+    extrapolateRight: "clamp",
+    extrapolateLeft: "clamp",
+    easing: Easing.bezier(0.16, 1, 0.3, 1),
+  });
+
+  return <div style={{ opacity }}>Hello World!</div>;
+};
+```
+
+CSS transitions or animations are FORBIDDEN - they will not render correctly.  
+Tailwind animation class names are FORBIDDEN - they will not render correctly.
+
+Place assets in the `public/` folder at your project root.
+
+Use `staticFile()` to reference files from the `public/` folder.
+
+Add images using the `<Img>` component:
+
+```tsx
+import { Img, staticFile } from "remotion";
+
+export const MyComposition = () => {
+  return <Img src={staticFile("logo.png")} style={{ width: 100, height: 100 }} />;
+};
+```
+
+Add videos using the `<Video>` component from `@remotion/media`:
+
+```tsx
+import { Video } from "@remotion/media";
+import { staticFile } from "remotion";
+
+export const MyComposition = () => {
+  return <Video src={staticFile("video.mp4")} style={{ opacity: 0.5 }} />;
+};
+```
+
+Add audio using the `<Audio>` component from `@remotion/media`:
+
+```tsx
+import { Audio } from "@remotion/media";
+import { staticFile } from "remotion";
+
+export const MyComposition = () => {
+  return <Audio src={staticFile("audio.mp3")} />;
+};
+```
+
+Assets can be also referenced as remote URLs:
+
+```tsx
+import { Video } from "@remotion/media";
+
+export const MyComposition = () => {
+  return <Video src="https://remotion.media/video.mp4" />
+};
+```
+
+To delay content wrap it in `<Sequence>` and use `from`.
+To limit the duration of an element, use `durationInFrames` of `<Sequence>`.
+`<Sequence>` by default is an absolute fill. For inline content, use `layout="none"`.
+
+```tsx
+import { Sequence } from "remotion";
+
+export const Title = () => {
+  const frame = useCurrentFrame();
+  const { fps } = useVideoConfig();
+
+  const opacity = interpolate(frame, [0, 2 * fps], [0, 1], {
+    extrapolateRight: "clamp",
+    extrapolateLeft: "clamp",
+    easing: Easing.bezier(0.16, 1, 0.3, 1),
+  });
+
+  return <div style={{ opacity }}>Title</div>;
+};
+
+export const Subtitle = () => {
+  return <div>Subtitle</div>;
+};
+
+const Main = () => {
+  const {fps} = useVideoConfig();
+
+  return (
+    <AbsoluteFill>
+      <Sequence>
+        <Background />
+      </Sequence>
+      <Sequence from={1 * fps} durationInFrames={2 * fps} layout="none">
+        <Title />
+      </Sequence>
+      <Sequence from={2 * fps} durationInFrames={2 * fps} layout="none">
+        <Subtitle />
+      </Sequence>
+    </AbsoluteFill>
+  );
+}
+```
+
+The width, height, fps, and duration of a video is defined in `src/Root.tsx`:
+
+```tsx
+import { Composition } from "remotion";
+import { MyComposition } from "./MyComposition";
+
+export const RemotionRoot = () => {
+  return (
+    <Composition
+      id="MyComposition"
+      component={MyComposition}
+      durationInFrames={100}
+      fps={30}
+      width={1080}
+      height={1080}
+    />
+  );
+};
+```
+
+Metadata can also be calculated dynamically:
+
+```tsx
+import { Composition, CalculateMetadataFunction } from "remotion";
+import { MyComposition, MyCompositionProps } from "./MyComposition";
+
+const calculateMetadata: CalculateMetadataFunction<
+  MyCompositionProps
+> = async ({ props, abortSignal }) => {
+  const data = await fetch(`https://api.example.com/video/${props.videoId}`, {
+    signal: abortSignal,
+  }).then((res) => res.json());
+
+  return {
+    durationInFrames: Math.ceil(data.duration * 30),
+    props: {
+      ...props,
+      videoUrl: data.url,
+    },
+    width: 1080,
+    height: 1080,
+  };
+};
+
+export const RemotionRoot = () => {
+  return (
+    <Composition
+      id="MyComposition"
+      component={MyComposition}
+      fps={30}
+      width={1080}
+      height={1080}
+      defaultProps={{ videoId: "abc123" }}
+      calculateMetadata={calculateMetadata}
+    />
+  );
+};
+```
+
+## Starting preview
+
+Start the Remotion Studio to preview a video:
+
+```bash
+npx remotion studio
+```
+
+## Optional: one-frame render check
+
+You can render a single frame with the CLI to sanity-check layout, colors, or timing.  
+Skip it for trivial edits, pure refactors, or when you already have enough confidence from Studio or prior renders.
+
+```bash
+npx remotion still [composition-id] --scale=0.25 --frame=30
+```
+
+At 30 fps, `--frame=30` is the one-second mark (`--frame` is zero-based).
+
+## Captions
+
+When dealing with captions or subtitles, load the [./rules/subtitles.md](./rules/subtitles.md) file for more information.
+
+## Using FFmpeg
+
+For some video operations, such as trimming videos or detecting silence, FFmpeg should be used. Load the [./rules/ffmpeg.md](./rules/ffmpeg.md) file for more information.
+
+## Silence detection
+
+When needing to detect and trim silent segments from video or audio files, load the [./rules/silence-detection.md](./rules/silence-detection.md) file.
+
+## Audio visualization
+
+When needing to visualize audio (spectrum bars, waveforms, bass-reactive effects), load the [./rules/audio-visualization.md](./rules/audio-visualization.md) file for more information.
+
+## Sound effects
+
+When needing to use sound effects, load the [./rules/sfx.md](./rules/sfx.md) file for more information.
+
+## 3D content
+
+See [rules/3d.md](rules/3d.md) for 3D content in Remotion using Three.js and React Three Fiber.
+
+## Advanced audio
+
+See [rules/audio.md](rules/audio.md) for advanced audio features like trimming, volume, speed, pitch.
+
+## Dynamic duration, dimensions and data
+
+See [rules/calculate-metadata.md](rules/calculate-metadata.md) for dynamically set composition duration, dimensions, and props.
+
+## Advanced compositions
+
+See [rules/compositions.md](rules/compositions.md) for how to define stills, folders, default props and for how to nest compositions.
+
+## Google Fonts
+
+Is the recommended way to load fonts in Remotion. See [rules/google-fonts.md](rules/google-fonts.md) for how to load Google Fonts.
+
+## Local fonts
+
+See [rules/local-fonts.md](rules/local-fonts.md) for how to load local fonts.
+
+## Getting audio duration
+
+See [rules/get-audio-duration.md](rules/get-audio-duration.md) for getting the duration of an audio file in seconds with Mediabunny.
+
+## Getting video dimensions
+
+See [rules/get-video-dimensions.md](rules/get-video-dimensions.md) for getting the width and height of a video file with Mediabunny.
+
+## Getting video duration
+
+See [rules/get-video-duration.md](rules/get-video-duration.md) for getting the duration of a video file in seconds with Mediabunny.
+
+## GIFs
+
+See [rules/gifs.md](rules/gifs.md) for how to display GIFs synchronized with Remotion's timeline.
+
+## Advanced Images
+
+See [rules/images.md](rules/images.md) for sizing and positioning images, dynamic image paths, and getting image dimensions.
+
+## Light leaks
+
+See [rules/light-leaks.md](rules/light-leaks.md) for light leak overlay effects using `@remotion/light-leaks`.
+
+## Lottie animations
+
+See [rules/lottie.md](rules/lottie.md) for embedding Lottie animations in Remotion.
+
+## HTML in canvas
+
+See [rules/html-in-canvas.md](rules/html-in-canvas.md) if you need to render HTML into a `<canvas>` to apply 2D or WebGL effects via `<HtmlInCanvas>`.
+
+## Measuring DOM nodes
+
+See [rules/measuring-dom-nodes.md](rules/measuring-dom-nodes.md) for measuring DOM element dimensions in Remotion.
+
+## Measuring text
+
+See [rules/measuring-text.md](rules/measuring-text.md) for measuring text dimensions, fitting text to containers, and checking overflow.
+
+## Advanced sequencing
+
+See [rules/sequencing.md](rules/sequencing.md) for more sequencing patterns - delay, trim, limit duration of items.
+
+## TailwindCSS
+
+See [rules/tailwind.md](rules/tailwind.md) for using TailwindCSS in Remotion.
+
+## Text animations
+
+See [rules/text-animations.md](rules/text-animations.md) for typography and text animation patterns.
+
+## Advanced timing
+
+See [rules/timing.md](rules/timing.md) for advanced timing with `interpolate` and Bézier easing, and springs.
+
+## Transitions
+
+See [rules/transitions.md](rules/transitions.md) for scene transition patterns.
+
+## Transparent videos
+
+See [rules/transparent-videos.md](rules/transparent-videos.md) for rendering out a video with transparency.
+
+## Trimming
+
+See [rules/trimming.md](rules/trimming.md) for trimming patterns - cutting the beginning or end of animations.
+
+## Advanced Videos
+
+See [rules/videos.md](rules/videos.md) for advanced knowledge about embedding videos - trimming, volume, speed, looping, pitch.
+
+## Parameterized videos
+
+See [rules/parameters.md](rules/parameters.md) for making a composition parametrizable by adding a Zod schema.
+
+## Maps
+
+For simple maps with little flyovers, consider just using a static images for maps.
+For complex maps with many flyovers, consider using Mapbox and animating it. Instructions: [rules/mapbox.md](rules/mapbox.md)
+
+## Voiceover
+
+See [rules/voiceover.md](rules/voiceover.md) for adding AI-generated voiceover to Remotion compositions using ElevenLabs TTS.