> ## Documentation Index
> Fetch the complete documentation index at: https://hyperframes.heygen.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Beat Accent

> A single music-hit sting: impact flash, micro scale-pulse on the subject, immediate decay.

export const InstallCommand = ({command}) => {
  const [copied, setCopied] = React.useState(false);
  const copy = async () => {
    try {
      if (navigator.clipboard && window.isSecureContext) {
        await navigator.clipboard.writeText(command);
      } else {
        const previous = document.activeElement;
        const scratch = document.createElement("textarea");
        scratch.value = command;
        scratch.setAttribute("readonly", "");
        scratch.style.position = "fixed";
        scratch.style.opacity = "0";
        document.body.appendChild(scratch);
        scratch.select();
        document.execCommand("copy");
        document.body.removeChild(scratch);
        previous?.focus?.();
      }
      setCopied(true);
      setTimeout(() => setCopied(false), 2000);
    } catch {}
  };
  return <div className="hf-install-command not-prose my-4 flex items-stretch overflow-hidden rounded-xl border border-zinc-200 bg-zinc-50 dark:border-zinc-800 dark:bg-zinc-900">
      <code className="flex-1 overflow-x-auto whitespace-nowrap border-r border-zinc-200 px-4 py-3 font-mono text-sm text-zinc-800 dark:border-zinc-800 dark:text-zinc-100">
        {command}
      </code>
      <button type="button" onClick={copy} data-copied={copied ? "true" : "false"} aria-label={`Copy ${command} to the clipboard`} className="hf-install-copy">
        <svg className="hf-install-copy-clipboard" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 18 18" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
          <path d="M14.25 5.25H7.25C6.14543 5.25 5.25 6.14543 5.25 7.25V14.25C5.25 15.3546 6.14543 16.25 7.25 16.25H14.25C15.3546 16.25 16.25 15.3546 16.25 14.25V7.25C16.25 6.14543 15.3546 5.25 14.25 5.25Z" />
          <path d="M2.80103 11.998L1.77203 5.07397C1.61003 3.98097 2.36403 2.96397 3.45603 2.80197L10.38 1.77297C11.313 1.63397 12.19 2.16297 12.528 3.00097" />
        </svg>
        <svg className="hf-install-copy-check" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 18 18" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
          <path d="M2.75 9.5L6.5 13.25L15.25 4.5" />
        </svg>
      </button>
      <span className="hf-install-copy-status" role="status" aria-live="polite">
        {copied ? "Copied" : ""}
      </span>
    </div>;
};

<iframe className="w-full aspect-video rounded-xl border-0 bg-zinc-100 dark:bg-zinc-800" title="beat-accent preview" loading="lazy" srcDoc={`<!doctype html><html><head><meta charset="utf-8"><style>html,body{margin:0;height:100%;overflow:hidden;background:transparent}hyperframes-player{display:block;width:100%;height:100%}</style><script src="https://cdn.jsdelivr.net/npm/@hyperframes/player@0.7/dist/hyperframes-player.global.js"><\/script></head><body><script>fetch("/public/catalog/components/beat-accent.json").then(function(r){return r.json()}).then(function(d){var p=document.createElement("hyperframes-player");p.setAttribute("srcdoc",d.html);p.setAttribute("controls","");p.setAttribute("autoplay","");p.setAttribute("loop","");p.setAttribute("muted","");p.setAttribute("poster","https://static.heygen.ai/hyperframes-oss/docs/images/catalog/components/beat-accent.png");document.body.appendChild(p)});<\/script></body></html>`} />

## Install

<InstallCommand command="npx hyperframes add beat-accent" />

That writes one file: `compositions/components/beat-accent.html`.

## Paste it into your composition

Open `compositions/components/beat-accent.html` and copy what is inside into your own composition.

A component has no size or duration of its own. It takes both from the composition
you paste it into.

## Variables

Every one of these has a default, so the piece works untouched. Set the ones you
want to change on the element:

| Variable     | Default  | Accepts                    | What it does                                       |
| ------------ | -------- | -------------------------- | -------------------------------------------------- |
| `text`       | `BOOM`   | string                     | Word or short label emphasized by the beat hit.    |
| `flashColor` | `accent` | `accent`, `soft`, `bright` | Token-backed accent tone used by the radial flash. |
| `intensity`  | `1`      | 0.5 to 2, step 0.1         | Strength of the scale pulse, flash, and shake.     |

Set them with `data-variable-values` on the element that mounts it. These are the
defaults, so this behaves exactly like the preview above until you change one:

```html wrap theme={null}
<div
  data-composition-id="beat-accent"
  data-composition-src="compositions/components/beat-accent.html"
  data-variable-values='{"text":"BOOM","flashColor":"accent","intensity":1}'
></div>
```

## Source

<Accordion title={`beat-accent.html`}>
  ```html theme={null}
  <!doctype html>
  <!--
    beat-accent: HyperFrames video primitive (effects / burst / emphasize)

    Concept: a single music-hit sting. A centered word snaps up in scale as a
    radial impact flash erupts behind it, shakes by a small amount, then settles
    immediately. One mechanic, one job: visual punctuation on one beat during IN.
    This burst fires once and never loops. HOLD stays deliberately calm and still
    after the decay.

    Compiled-from evidence: Video Primitives v1 GAP C1, "sting: impact
    flash/scale on a music hit." The candidates catalog describes a C1 gap:
    music-driven films need visual punctuation on the downbeat and had nothing
    atomic to reach for. A declared sync point makes the primitive weldable to
    any audio hit. Catalog shelf: effects / burst / emphasize. The impact uses
    the easing vocabulary's --ease-slam, GSAP expo.out, with the CSS mirror
    cubic-bezier(0.19, 1, 0.22, 1), kept brief per taste rule 3.

    Use when: one downbeat, edit point, reveal, or hard musical hit needs a short
    visual accent. Mount it over the subject or use its centered word as the
    subject. Do not use it as an ambient loop or a repeated visualizer.

    Variables (declared in data-composition-variables below):
      - text (string, default "BOOM"): the word or label that receives the hit.
      - flashColor (enum, default "accent"): accent, soft accent, or bright
        accent. Every option is derived from var(--accent), so theme changes
        always repaint the flash.
      - intensity (number, 0.5 to 2, default 1, step 0.1): scales subject pulse,
        flash opacity and spread, and shake distance as one legible control.

    Envelope (fixed IN/OUT, elastic HOLD only, never gsap.timeScale()):
      IN_BASE  = 0.90s, calm lead, impact snap, flash, shake, and full decay
      HOLD     = elastic = max(0, D - (IN_BASE + OUT_BASE)), deliberately still
      OUT_BASE = 0.40s, clean release fade
      If D < IN_BASE + OUT_BASE, IN and OUT scale down together so IN + OUT == D
      and HOLD == 0. All fixed offsets and motion durations use the same scale.

    Sync point: impact-hard lands at IMPACT_AT = 0.25s into an unscaled IN. It
    scales proportionally only when the full envelope is compressed. ADR-0007
    requires declared sync points to remain in a fixed phase, never inside the
    elastic HOLD, so audio and visual timing cannot drift as duration changes.

    Sound cue: the primitive never plays audio. At IMPACT_AT it dispatches a
    bubbling `hf:sfx` CustomEvent with detail { id: "impact-hard", t: IMPACT_AT }.
    A host mix stage may catch that event and route the id to its chosen asset.

    Mount contract: this file is a MOUNTABLE SUB-COMPOSITION, not a standalone
    composition. A host loads it via data-composition-src; the runtime clones
    only <template> contents, while everything outside <template>, including
    <head>, is discarded on mount. #root has no data-width or data-height. It is
    styled by id, never by class, and fills the host box with position:absolute,
    inset:0, container-type:size. Variables are read through
    window.__hyperframes.getVariables(), never by parsing document.documentElement,
    because the mounted document element belongs to the host composition.
  -->
  <html
    lang="en"
    data-composition-variables='[
      { "id": "text", "type": "string", "role": "content", "label": "Accent text", "description": "Word or short label emphasized by the beat hit.", "default": "BOOM" },
      { "id": "flashColor", "type": "enum", "role": "style", "label": "Flash color", "description": "Token-backed accent tone used by the radial flash.", "default": "accent", "options": [{ "value": "accent", "label": "Accent" }, { "value": "soft", "label": "Soft accent" }, { "value": "bright", "label": "Bright accent" }] },
      { "id": "intensity", "type": "number", "role": "timing", "label": "Intensity", "description": "Strength of the scale pulse, flash, and shake.", "default": 1, "min": 0.5, "max": 2, "step": 0.1 }
    ]'
  >
    <head>
      <meta charset="UTF-8" />
      <title>Beat Accent</title>
    </head>
    <body>
      <template>
        <div id="root" data-composition-id="beat-accent" data-duration="4" data-fps="30">
          <style>
            *,
            *::before,
            *::after {
              box-sizing: border-box;
            }

            #root {
              --ease-slam: cubic-bezier(0.19, 1, 0.22, 1);
              --ba-flash-color: var(--accent, #ff4f8b);
              position: absolute;
              inset: 0;
              container-type: size;
              isolation: isolate;
              overflow: hidden;
              background: var(--bg, #0b1120);
              color: var(--fg, #f8fafc);
              font-family: var(--font-body, system-ui, sans-serif);
              pointer-events: none;
            }

            .ba-clip {
              position: absolute;
              inset: 0;
              display: grid;
              place-items: center;
              overflow: hidden;
            }

            .ba-stage {
              position: relative;
              width: 100%;
              height: 100%;
              display: grid;
              place-items: center;
              will-change: transform, opacity;
            }

            .ba-flash {
              position: absolute;
              width: 62cqw;
              aspect-ratio: 1;
              border-radius: 50%;
              background: radial-gradient(
                circle,
                color-mix(in srgb, var(--ba-flash-color) 92%, transparent) 0%,
                color-mix(in srgb, var(--ba-flash-color) 54%, transparent) 24%,
                color-mix(in srgb, var(--ba-flash-color) 16%, transparent) 48%,
                transparent 72%
              );
              opacity: 0;
              will-change: transform, opacity;
            }

            .ba-flash::after {
              content: "";
              position: absolute;
              inset: 22%;
              border: 0.45cqmin solid color-mix(in srgb, var(--ba-flash-color) 78%, transparent);
              border-radius: 50%;
            }

            .ba-subject {
              position: relative;
              z-index: 1;
              display: block;
              width: 86cqw;
              color: var(--fg, #f8fafc);
              font-family: var(--font-display, var(--font-body, system-ui, sans-serif));
              font-size: 20cqmin;
              font-weight: 900;
              line-height: 0.9;
              letter-spacing: -0.055em;
              text-align: center;
              text-transform: uppercase;
              white-space: nowrap;
              overflow: hidden;
              text-overflow: ellipsis;
              text-shadow:
                0 0 2cqmin color-mix(in srgb, var(--accent, #ff4f8b) 46%, transparent),
                0 1.2cqh 3.8cqh color-mix(in srgb, var(--bg, #0b1120) 68%, transparent);
              transform-origin: 50% 50%;
              will-change: transform;
            }
          </style>

          <div
            id="beat-accent-clip"
            class="ba-clip clip"
            data-start="0"
            data-duration="4"
            data-track-index="0"
          >
            <div class="ba-stage">
              <div class="ba-flash" aria-hidden="true"></div>
              <div class="ba-subject"></div>
            </div>
          </div>

          <script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
          <script>
            (function () {
              "use strict";

              var root = document.getElementById("root");
              var stage = root.querySelector(".ba-stage");
              var flash = root.querySelector(".ba-flash");
              var subject = root.querySelector(".ba-subject");
              var vars =
                window.__hyperframes && window.__hyperframes.getVariables
                  ? window.__hyperframes.getVariables()
                  : {};

              var text = vars.text == null ? "BOOM" : String(vars.text);
              var flashChoice =
                vars.flashColor === "soft" || vars.flashColor === "bright"
                  ? vars.flashColor
                  : "accent";
              var intensityValue = Number(vars.intensity);
              var intensity = Number.isFinite(intensityValue)
                ? Math.max(0.5, Math.min(2, intensityValue))
                : 1;

              var flashColors = {
                accent: "var(--accent, #ff4f8b)",
                soft: "color-mix(in srgb, var(--accent, #ff4f8b) 70%, var(--bg, #0b1120))",
                bright: "color-mix(in srgb, var(--accent, #ff4f8b) 72%, var(--fg, #f8fafc))",
              };

              subject.textContent = text;
              root.style.setProperty("--ba-flash-color", flashColors[flashChoice]);

              var IN_BASE = 0.9;
              var OUT_BASE = 0.4;
              var IMPACT_AT_BASE = 0.25;
              var SNAP_BASE = 0.12;
              var SETTLE_BASE = 0.28;
              var FLASH_IN_BASE = 0.08;
              var FLASH_OUT_BASE = 0.28;

              var duration = Math.max(0.001, parseFloat(root.dataset.duration || "4"));
              var totalBase = IN_BASE + OUT_BASE;
              var envelopeScale = duration < totalBase ? duration / totalBase : 1;
              var IN = IN_BASE * envelopeScale;
              var OUT = OUT_BASE * envelopeScale;
              var IMPACT_AT = IMPACT_AT_BASE * envelopeScale;
              var SNAP = SNAP_BASE * envelopeScale;
              var SETTLE = SETTLE_BASE * envelopeScale;
              var FLASH_IN = FLASH_IN_BASE * envelopeScale;
              var FLASH_OUT = FLASH_OUT_BASE * envelopeScale;
              var HOLD = Math.max(0, duration - (IN + OUT));
              var OUT_START = IN + HOLD;

              var restScale = 1 - 0.06 * intensity;
              var peakScale = 1 + 0.18 * intensity;
              var flashPeakScale = 0.78 + 0.3 * intensity;
              var flashEndScale = 1.08 + 0.32 * intensity;
              var flashPeakOpacity = Math.min(0.96, 0.5 + 0.23 * intensity);
              var shakeX = 0.9 * intensity;
              var shakeY = 0.34 * intensity;

              gsap.set(stage, { x: 0, y: 0, opacity: 1 });
              gsap.set(subject, { scale: restScale });
              gsap.set(flash, { scale: 0.25, opacity: 0 });

              var tl = gsap.timeline({ paused: true });

              tl.to(subject, { scale: peakScale, duration: SNAP, ease: "expo.out" }, IMPACT_AT);
              tl.to(subject, { scale: 1, duration: SETTLE, ease: "power3.out" }, IMPACT_AT + SNAP);

              tl.to(
                flash,
                {
                  scale: flashPeakScale,
                  opacity: flashPeakOpacity,
                  duration: FLASH_IN,
                  ease: "expo.out",
                },
                IMPACT_AT,
              );
              tl.to(
                flash,
                { scale: flashEndScale, opacity: 0, duration: FLASH_OUT, ease: "power3.out" },
                IMPACT_AT + FLASH_IN,
              );

              tl.to(
                stage,
                {
                  x: shakeX + "cqw",
                  y: -shakeY + "cqh",
                  duration: 0.04 * envelopeScale,
                  ease: "none",
                },
                IMPACT_AT,
              );
              tl.to(
                stage,
                {
                  x: -shakeX * 0.7 + "cqw",
                  y: shakeY * 0.75 + "cqh",
                  duration: 0.05 * envelopeScale,
                  ease: "none",
                },
                IMPACT_AT + 0.04 * envelopeScale,
              );
              tl.to(
                stage,
                {
                  x: shakeX * 0.3 + "cqw",
                  y: -shakeY * 0.35 + "cqh",
                  duration: 0.05 * envelopeScale,
                  ease: "none",
                },
                IMPACT_AT + 0.09 * envelopeScale,
              );
              tl.to(
                stage,
                {
                  x: 0,
                  y: 0,
                  duration: 0.12 * envelopeScale,
                  ease: "power3.out",
                },
                IMPACT_AT + 0.14 * envelopeScale,
              );

              tl.call(
                function () {
                  root.dispatchEvent(
                    new CustomEvent("hf:sfx", {
                      detail: { id: "impact-hard", t: IMPACT_AT },
                      bubbles: true,
                    }),
                  );
                },
                [],
                IMPACT_AT,
              );

              tl.to(stage, { opacity: 0, duration: OUT, ease: "power2.out" }, OUT_START);
              tl.seek(0);

              window.__timelines = window.__timelines || {};
              // Literal id is required. Mount flattening strips data-composition-id
              // from this inner root, so reading the id from root would register
              // under null and leave the host unable to find this timeline.
              window.__timelines["beat-accent"] = tl;
            })();
          </script>
        </div>
      </template>
    </body>
  </html>
  ```
</Accordion>

Tagged `motion-primitive` `effects` `burst` `sting` `emphasize` `impact`.

## Related topics

* [Browse the complete Catalog](/catalog)
* [Add assets and Catalog items in Studio](/studio/assets-and-blocks)
* [Build a richer composition](/go-further)


## Related topics

- [Beat Freeze Cut](/catalog/blocks/beat-freeze-cut.md)
- [Beat Pulse Background](/catalog/components/beat-pulse-background.md)
- [Icon Morph Beat](/catalog/components/icon-morph-beat.md)
