Install
That writes one file:compositions/mk-callout-highlight.html.
Add it to your video
It runs for 8 seconds at 1920×1080. Paste this into your composition:index.html
<div
data-composition-id="mk-callout-highlight"
data-composition-src="compositions/mk-callout-highlight.html"
data-start="0"
data-duration="8"
data-track-index="1"
data-width="1920"
data-height="1080"
></div>
data-start. Put it on a different timeline row with
data-track-index. See data attributes for the rest.
Source
mk-callout-highlight.html
mk-callout-highlight.html
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
<style>
*,
*::before,
*::after {
margin: 0;
padding: 0;
box-sizing: border-box;
}
body {
background: transparent;
overflow: hidden;
}
#mk-ch-root {
/* ---- mk tokens: override in the host to re-skin the family ---- */
--mk-font: "Inter", -apple-system, sans-serif;
--mk-ink: #1d1d1f;
/* faint = transient pre-sweep tier (tweens up to full ink) — distinct from the family --mk-ink-dim */
--mk-ink-faint: #bcbcc2;
--mk-ink-dark: #f5f5f7;
--mk-ink-faint-dark: rgba(245, 245, 247, 0.32);
position: relative;
width: 1920px;
height: 1080px;
overflow: hidden;
background: transparent; /* overlays footage or mk-background */
}
#mk-ch-box {
position: absolute;
font-family: var(--mk-font);
font-weight: 500;
letter-spacing: -0.015em;
}
.mk-ch-word {
display: inline;
}
</style>
</head>
<body>
<div
id="mk-ch-root"
data-composition-id="mk-callout-highlight"
data-start="0"
data-duration="8"
data-width="1920"
data-height="1080"
>
<div id="mk-ch-box" data-layout-allow-occlusion></div>
<div
id="mk-ch-drv"
class="clip"
data-start="0"
data-duration="8"
data-track-index="0"
style="position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none"
></div>
</div>
<script>
(function () {
window.__timelines = window.__timelines || {};
/* ---- published parameters (inspector-style CONFIG) ----
The mechanic: one scalar (highlight progress 0..1) sweeps word-by-word
emphasis across the sentence — a "highlight amount"
slider. Tween the scalar over the speaker's sentence to follow speech. */
var CONFIG = {
scheme: "light", // "light" (ink on light bg) | "dark" (white on footage)
text: "Functionality was our goal from the very beginning",
fontSize: 60,
lineHeight: 1.3,
maxWidth: 700, // px; sentence wraps inside this
x: 1030, // box left edge; null = centered horizontally
y: null, // box top edge; null = centered vertically
align: "left",
sweep: { start: 1.2, end: 6.2 }, // block-local seconds, linear
animationIn: true, // fade/rise entrance before the sweep
animationOut: true,
};
var DUR = 8;
var root = document.getElementById("mk-ch-root");
var box = document.getElementById("mk-ch-box");
var FULL = CONFIG.scheme === "dark" ? "#f5f5f7" : "#1d1d1f";
var FAINT = CONFIG.scheme === "dark" ? "rgba(245,245,247,0.32)" : "#bcbcc2";
box.style.fontSize = CONFIG.fontSize + "px";
box.style.lineHeight = String(CONFIG.lineHeight);
box.style.maxWidth = CONFIG.maxWidth + "px";
box.style.textAlign = CONFIG.align;
/* build word spans */
var wordEls = [];
CONFIG.text.split(/\s+/).forEach(function (w, i) {
if (i > 0) box.appendChild(document.createTextNode(" "));
var span = document.createElement("span");
span.id = "mk-ch-w-" + i;
span.className = "mk-ch-word";
span.textContent = w;
span.style.color = FAINT;
box.appendChild(span);
wordEls.push(span);
});
/* position (measure after building) */
var rect = box.getBoundingClientRect();
box.style.left =
(CONFIG.x === null ? Math.round((1920 - rect.width) / 2) : CONFIG.x) + "px";
box.style.top =
(CONFIG.y === null ? Math.round((1080 - rect.height) / 2) : CONFIG.y) + "px";
/* state proxy: GSAP animates st.p, render derives every word color from it */
var st = { p: 0 };
var mix = gsap.utils.interpolate(FAINT, FULL);
function render() {
var k = st.p * wordEls.length;
for (var i = 0; i < wordEls.length; i++) {
var f = Math.max(0, Math.min(1, k - i));
wordEls[i].style.color = mix(f);
}
}
var tl = gsap.timeline({ paused: true });
if (CONFIG.animationIn) {
gsap.set(box, { opacity: 0, y: 24 });
tl.to(box, { opacity: 1, y: 0, duration: 0.7, ease: "power3.out" }, 0.3);
}
/* the highlight sweep — one scalar, linear so it tracks speech evenly.
To follow a real voiceover, replace with several tweens between
per-phrase progress values (keyframes on the slider). */
tl.to(
st,
{ p: 1, duration: CONFIG.sweep.end - CONFIG.sweep.start, ease: "none" },
CONFIG.sweep.start,
);
if (CONFIG.animationOut) {
tl.to(box, { opacity: 0, y: -16, duration: 0.4, ease: "power2.in" }, DUR - 0.5);
}
tl.set(root, { visibility: "hidden" }, DUR - 0.02);
tl.eventCallback("onUpdate", render);
render();
window.__timelines["mk-callout-highlight"] = tl;
})();
</script>
</body>
</html>
typography karaoke captions minimal.