heygen-com--hyperframes/skills/hyperframes-animation/rules/asr-keyword-glow.md

name, description, metadata

name	description	metadata
asr-keyword-glow	Keywords glow + scale up when "spoken" — attack/sustain/release envelope synced to per-word timestamps. Even without real audio, hardcoded timings create a "narrator emphasis" effect.	tags asr, audio-sync, highlight, glow, keyword, text, speech, emphasis

ASR Keyword Glow

Words in a phrase visually activate (glow blur + scale) when "spoken," following an attack-sustain-release (ASR-like) envelope. In a real ASR pipeline these timings come from word-level transcript data; for promotional video, hardcode the timings to control emphasis pacing. The envelope leaves a subtle "rest glow" after the word, creating a breadcrumb of recent emphasis.

How It Works

Each word has { start, end } timestamps. At each frame, compute the word's envelope value:

• Pre-start → 0 (not yet)
• Start → peak → attack (linear ramp 0 → 1)
• Peak → end → sustain (stays at 1)
• End → end+release → decay (1 → restLevel, typically 0.25)
• After release → restLevel (stays subtly highlighted)

The envelope drives textShadow blur radius AND scale. Higher blur + bigger scale = "speaking" emphasis.

HTML

<div
  class="scene"
  id="asr-scene"
  data-composition-id="asr-scene"
  data-start="0"
  data-duration="6"
  data-track-index="0"
>
  <div class="phrase">
    <!-- One <span class="word"> per word in {phrase}. data-word is a
         stable key used to look up the word's ASR timing in JS. The
         final word may be a {brandWord}, which gets longer emphasis
         and the .brand modifier. -->
    <span class="word" data-word="{w1Key}">{w1}</span>
    <span class="word" data-word="{w2Key}">{w2}</span>
    <!-- … -->
    <span class="word brand" data-word="{brandKey}">{brandWord}</span>
  </div>
</div>

CSS

.scene {
  position: relative;
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
  background: {sceneBackgroundColor};
  font-family: {font};
}
.phrase {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
  max-width: 1700px;
  font-size: 120px;
  font-weight: 900;
  letter-spacing: 2px;
  color: {restColor};
  text-align: center;
  line-height: 1.2;
}
.word {
  display: inline-block;
  transform-origin: 50% 50%;
  /* Initial subtle rest glow */
  text-shadow: 0 0 0 {glowColorTransparent};
  will-change: transform, text-shadow;
}
.word.brand {
  color: {brandAccentColor};
  letter-spacing: 12px;
  text-transform: uppercase;
}

GSAP Timeline

<script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
<script>
  window.__timelines = window.__timelines || {};
  const tl = gsap.timeline({ paused: true });

  // Per-word "spoken" times — author these to control narrator pacing.
  // Shape: { [wordKey]: { start, end } } in local seconds. One entry
  // per <span class="word" data-word="…">. The brand word's window is
  // typically 1.5-2× as long as a normal word.
  const TIMINGS = {
    // {w1Key}: { start: …, end: … },
    // {w2Key}: { start: …, end: … },
    // …
    // {brandKey}: { start: …, end: … },
  };

  function envelope(time, start, end) {
    const releaseEnd = end + RELEASE;
    if (time < start) return 0;
    if (time < end) {
      // attack — linear ramp over ATTACK_DUR then sustain
      const attack = Math.min((time - start) / ATTACK_DUR, 1);
      return attack;
    }
    if (time < releaseEnd) {
      // decay to rest level
      const decay = (time - end) / RELEASE;
      return 1 - decay * (1 - REST_LEVEL);
    }
    return REST_LEVEL;
  }

  const words = document.querySelectorAll(".word");

  // Single driver — 0 → composition duration
  const driver = { t: 0 };
  tl.to(
    driver,
    {
      t: SCENE_DURATION,
      duration: SCENE_DURATION,
      ease: "none",
      onUpdate: () => {
        words.forEach((el) => {
          const word = el.dataset.word;
          const timing = TIMINGS[word];
          if (!timing) return;
          const env = envelope(driver.t, timing.start, timing.end);
          const blur = MAX_BLUR * env;
          const scale = 1 + MAX_SCALE_BOOST * env;
          el.style.textShadow = `0 0 ${blur}px ${glowColorRgba(env)}`;
          el.style.transform = `scale(${scale})`;
        });
      },
    },
    0,
  );

  window.__timelines["asr-scene"] = tl;
</script>

glowColorRgba(env) returns the brand glow color with env-modulated alpha (e.g. rgba({glowR}, {glowG}, {glowB}, ${GLOW_ALPHA_BASE + env * GLOW_ALPHA_RANGE})).

Variations

Multi-octave glow (more dramatic peaks)

Combine the envelope-driven blur with a sin pulse during the sustain phase — high-emphasis words breathe at peak. The sine frequency PULSE_HZ controls how many breaths fit in the sustain window; amplitude PULSE_AMPLITUDE controls how visible the breath is.

const sustain = env * (1 + Math.sin(driver.t * PULSE_HZ) * PULSE_AMPLITUDE);
const blur = MAX_BLUR * sustain;

Color shift on the peak

The active word lerps from restColor → peakColor as env rises, settling back to restColor at rest:

function lerpChannel(a, b, t) {
  return Math.round(a + (b - a) * t);
}
el.style.color = `rgb(${lerpChannel(REST_RGB.r, PEAK_RGB.r, env)}, ${lerpChannel(REST_RGB.g, PEAK_RGB.g, env)}, ${lerpChannel(REST_RGB.b, PEAK_RGB.b, env)})`;

Karaoke style (dim-rest + bright-active, RECOMMENDED for video narration)

Default amplitudes (small MAX_BLUR, small MAX_SCALE_BOOST, rest text full white) read as too subtle in video — the inactive words still dominate. Karaoke style fixes this: inactive words rendered DIM, active words lerp toward bright white + larger scale:

// Tunable constants — see How to Choose Values
// REST_RGB    — dim color for inactive words
// ACTIVE_RGB  — bright color at peak (non-brand)
// BRAND_RGB   — bright color at peak (brand word)
// MAX_BLUR, MAX_SCALE_BOOST, REST_LEVEL all pushed higher than default

function lerpChannel(a, b, t) {
  return Math.round(a + (b - a) * t);
}
function colorAt(env, isBrand) {
  const target = isBrand ? BRAND_RGB : ACTIVE_RGB;
  return `rgb(${lerpChannel(REST_RGB.r, target.r, env)}, ${lerpChannel(REST_RGB.g, target.g, env)}, ${lerpChannel(REST_RGB.b, target.b, env)})`;
}

// In onUpdate:
el.style.color = colorAt(env, el.classList.contains("brand"));

Visual result: at any moment 1-2 words are bright + glowing (the spoken word + the recently-spoken one's lingering rest), and the rest of the phrase is dim. This is closer to actual karaoke / lyric video aesthetic than the subtle "everyone half-glowing" baseline.

When to use karaoke vs default: short narration phrases (5-10 words) where one word at a time should clearly POP → karaoke. Long dense text where many words emphasize subtly → default subtle. Karaoke pushes MAX_BLUR, MAX_SCALE_BOOST, and contrast between REST_RGB and ACTIVE_RGB; everything else is identical.

3D pop-out

Combine envelope with translateZ for words to "lean toward camera" as they speak:

const popZ = env * MAX_POP_Z;
el.style.transform = `translateZ(${popZ}px) scale(${scale})`;

Requires perspective on the parent.

From real ASR transcripts

For real ASR-driven scenes, replace hardcoded TIMINGS with transcript JSON (each entry has word, start_ms, end_ms). Convert to seconds and feed in identically. The shape { [wordKey]: { start, end } } is the same whether hand-authored or derived from hyperframes transcribe.

How to Choose Values

• TIMINGS — per-word { start, end } map. Author one entry per .word span.
  • Shape: { wordKey: { start: number, end: number } }, all seconds local to the scene.
  • Constraints: monotonic non-overlap — every entry's end < next entry's start (overlapping windows make the envelope ambiguous).
  • Brand word window: typically 1.5-2× the average non-brand word window so the brand sustains.
• ATTACK_DUR — seconds for the envelope to ramp 0 → 1 once a word starts.
  • Range: 0.1-0.25 s
  • Effects: shorter feels punchy and ASR-like; longer feels smoothed-out.
  • Constraints: must be < (smallest word's end - start), otherwise the word never reaches 1.
• RELEASE — seconds for the envelope to decay 1 → REST_LEVEL after a word ends.
  • Range: 0.2-0.5 s
• REST_LEVEL — held envelope value after RELEASE.
  • Range: 0.15-0.4 (default style); 0.05-0.2 (karaoke style — dimmer rest).
  • Effects: lower = quieter breadcrumb; higher = more recently-spoken words stay bright.
  • Constraints: must be < 1; should be > 0 to preserve the breadcrumb.
• MAX_BLUR — peak text-shadow blur radius in px.
  • Range: 15-25 px (default style); 30-45 px (karaoke style).
  • Effects: bigger reads as "shouting"; smaller reads as "neutral narration".
• MAX_SCALE_BOOST — additive scale at peak (e.g. 0.08 ⇒ 1.0 → 1.08).
  • Range: 0.03-0.10 (default style); 0.15-0.25 (karaoke style).
  • Effects: bigger reads as "bouncy"; smaller reads as "just glowing".
• SCENE_DURATION — total seconds for the single driver tween.
  • Constraints: must equal the scene's data-duration so the driver t reaches the end of TIMINGS in sync with HF's seek.
• REST_RGB / ACTIVE_RGB / BRAND_RGB (karaoke style) — discrete color choices, not numeric.
  • REST_RGB: dim tone of the brand palette's neutral; should read as off-white-ish dim, not black.
  • ACTIVE_RGB: brand text color at full readability.
  • BRAND_RGB: brand accent color (often the same hue as the glow).
• PULSE_HZ / PULSE_AMPLITUDE (multi-octave variation) — sine breath frequency / depth.
  • PULSE_HZ range: 4-10 rad/s; PULSE_AMPLITUDE range: 0.1-0.3.
• MAX_POP_Z (3D pop-out variation) — max Z translation at peak (px).
  • Range: 20-60 px; requires parent perspective.

Ease family — discrete choice:

• Single linear driver (ease: "none") so t maps 1:1 to scene time. Any other ease distorts the per-word envelope shape — do not change.

Key Principles

• Envelope shape: attack-sustain-decay-rest — never zero out after a word. The rest level (REST_LEVEL > 0) keeps the recently-spoken words subtly highlighted, creating a "breadcrumb" of attention.
• Brand word gets longer emphasis (1.5-2× normal) — the brand is the headline; let it sustain.
• display: inline-block on each word — required for transform to apply to <span>.
• MAX_BLUR and MAX_SCALE_BOOST stay in their default-style ranges unless you commit to karaoke — picking values between default and karaoke yields awkward "half-loud" emphasis.
• Per-word text-shadow (not box-shadow) — text-shadow is the glow around the GLYPH, which is what reads as "speaking emphasis." Box-shadow would glow around the inline-block bounding box (rectangle).
• Single driver, multi-word onUpdate — one tween that loops over all words. Don't create one tween per word — at 60+ words the timeline becomes unwieldy.
• ❗ Climax dwell ≥1s — after the final word's emphasis, comp continues ≥1s. The last word IS the headline beat.

Critical Constraints

• Timeline must be paused: gsap.timeline({ paused: true })
• Registry key = data-composition-id
• No CSS animation on word elements
• display: inline-block on each .word
• will-change: transform, text-shadow on .word
• Timings monotonic (later start > earlier end) — overlapping words mess up the envelope

Combinations

• 3d-text-depth-layers.md — the active word gets depth-layered emphasis at peak
• sine-wave-loop.md — non-active words breathe subtly between emphasis moments
• context-sensitive-cursor.md — typewriter that types each word matching the ASR cadence

Pairs with HF skills

• /hyperframes-animation — single driver, multi-element envelope
• /media-use — hyperframes transcribe outputs real ASR data
• /media-use — pair with caption rendering
• /hyperframes-core — composition wiring
• /hyperframes-cli — hyperframes lint