> ## 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.

# Use voice, music, sound, and captions

> Build an understandable audio mix, transcribe real speech, and turn it into readable captions.

export const DocsVideo = ({src, poster, title, autoPlay = false, loop = false, portrait = false}) => {
  const videoRef = useRef(null);
  const playerRef = useRef(null);
  const hideTimerRef = useRef(null);
  const progressFrameRef = useRef(null);
  const [enhanced, setEnhanced] = useState(false);
  const [playing, setPlaying] = useState(false);
  const [waiting, setWaiting] = useState(false);
  const [muted, setMuted] = useState(false);
  const [currentTime, setCurrentTime] = useState(0);
  const [duration, setDuration] = useState(0);
  const [playbackRate, setPlaybackRate] = useState(1);
  const [controlsVisible, setControlsVisible] = useState(false);
  const [fullscreen, setFullscreen] = useState(false);
  const [fullscreenSupported, setFullscreenSupported] = useState(false);
  const [previewing, setPreviewing] = useState(false);
  const [scrubbing, setScrubbing] = useState(false);
  const [previewTime, setPreviewTime] = useState(0);
  const [previewPosition, setPreviewPosition] = useState(0);
  const formatTime = seconds => {
    if (!Number.isFinite(seconds) || seconds < 0) return "0:00";
    const minutes = Math.floor(seconds / 60);
    const remaining = Math.floor(seconds % 60);
    return `${minutes}:${String(remaining).padStart(2, "0")}`;
  };
  const clearHideTimer = () => {
    if (hideTimerRef.current) {
      window.clearTimeout(hideTimerRef.current);
      hideTimerRef.current = null;
    }
  };
  const revealControls = () => {
    setControlsVisible(true);
    clearHideTimer();
    hideTimerRef.current = window.setTimeout(() => setControlsVisible(false), 2200);
  };
  const togglePlayback = async () => {
    const video = videoRef.current;
    if (!video) return;
    if (video.paused || video.ended) {
      if (video.ended) video.currentTime = 0;
      setWaiting(true);
      try {
        await video.play();
      } catch {
        setWaiting(false);
        setPlaying(false);
      }
    } else {
      video.pause();
      setControlsVisible(true);
    }
  };
  const toggleMute = () => {
    const video = videoRef.current;
    if (!video) return;
    if (video.muted && video.volume === 0) video.volume = 0.8;
    video.muted = !video.muted;
    setMuted(video.muted);
  };
  const seek = event => {
    const video = videoRef.current;
    if (!video) return;
    const nextTime = Number(event.target.value);
    video.currentTime = nextTime;
    setCurrentTime(nextTime);
  };
  const updateScrubPreview = (event, seekMainVideo = false) => {
    if (!duration) return;
    const rect = event.currentTarget.getBoundingClientRect();
    const ratio = Math.min(1, Math.max(0, (event.clientX - rect.left) / rect.width));
    const nextTime = ratio * duration;
    setPreviewing(true);
    setPreviewTime(nextTime);
    setPreviewPosition(ratio * 100);
    if (seekMainVideo) {
      const video = videoRef.current;
      if (video) {
        video.currentTime = nextTime;
        setCurrentTime(nextTime);
      }
    }
  };
  const cyclePlaybackRate = () => {
    const video = videoRef.current;
    if (!video) return;
    const rates = [1, 1.25, 1.5, 2];
    const currentIndex = rates.indexOf(video.playbackRate);
    const nextRate = rates[(currentIndex + 1) % rates.length];
    video.playbackRate = nextRate;
    setPlaybackRate(nextRate);
  };
  const toggleFullscreen = async () => {
    const player = playerRef.current;
    const video = videoRef.current;
    if (!player || typeof document === "undefined") return;
    try {
      if (document.fullscreenElement) {
        await document.exitFullscreen();
      } else if (player.requestFullscreen) {
        await player.requestFullscreen();
      } else if (video?.webkitEnterFullscreen) {
        video.webkitEnterFullscreen();
      }
    } catch {}
  };
  const handleKeyboard = event => {
    if (event.target !== event.currentTarget) return;
    const video = videoRef.current;
    if (!video) return;
    if (event.key === " " || event.key === "Enter") {
      event.preventDefault();
      togglePlayback();
    } else if (event.key === "ArrowLeft") {
      event.preventDefault();
      video.currentTime = Math.max(0, video.currentTime - 5);
    } else if (event.key === "ArrowRight") {
      event.preventDefault();
      video.currentTime = Math.min(duration || video.duration || 0, video.currentTime + 5);
    } else if (event.key.toLowerCase() === "m") {
      event.preventDefault();
      toggleMute();
    } else if (event.key.toLowerCase() === "f") {
      event.preventDefault();
      toggleFullscreen();
    }
  };
  useEffect(() => {
    setEnhanced(true);
    setFullscreenSupported(Boolean(playerRef.current?.requestFullscreen || videoRef.current?.webkitEnterFullscreen));
    return () => {
      clearHideTimer();
    };
  }, []);
  useEffect(() => {
    if (typeof document === "undefined") return undefined;
    const syncFullscreen = () => setFullscreen(document.fullscreenElement === playerRef.current);
    document.addEventListener("fullscreenchange", syncFullscreen);
    return () => document.removeEventListener("fullscreenchange", syncFullscreen);
  }, []);
  useEffect(() => {
    clearHideTimer();
    if (!playing) return undefined;
    hideTimerRef.current = window.setTimeout(() => setControlsVisible(false), 2200);
    return clearHideTimer;
  }, [playing]);
  useEffect(() => {
    if (!playing) return undefined;
    const updateProgress = () => {
      const video = videoRef.current;
      if (video && !video.paused) setCurrentTime(video.currentTime);
      progressFrameRef.current = window.requestAnimationFrame(updateProgress);
    };
    progressFrameRef.current = window.requestAnimationFrame(updateProgress);
    return () => {
      if (progressFrameRef.current) window.cancelAnimationFrame(progressFrameRef.current);
      progressFrameRef.current = null;
    };
  }, [playing]);
  const progress = duration > 0 ? currentTime / duration * 100 : 0;
  const replaying = duration > 0 && currentTime >= duration - 0.15;
  return <div className="hf-docs-video-block" data-portrait={portrait ? "true" : "false"}>
      <div ref={playerRef} className="hf-docs-video" role="region" aria-label={title} tabIndex={0} onKeyDown={handleKeyboard} onPointerMove={revealControls} onPointerLeave={() => setControlsVisible(false)} onFocus={revealControls} onBlur={event => {
    if (!event.currentTarget.contains(event.relatedTarget)) setControlsVisible(false);
  }}>
        <video ref={videoRef} aria-label={title} src={src} poster={poster} autoPlay={autoPlay} loop={loop} playsInline preload="metadata" controls={!enhanced} onClick={togglePlayback} onDoubleClick={toggleFullscreen} onLoadedMetadata={event => {
    const nextDuration = event.currentTarget.duration || 0;
    setDuration(nextDuration);
    setMuted(event.currentTarget.muted);
  }} onDurationChange={event => setDuration(event.currentTarget.duration || 0)} onTimeUpdate={event => setCurrentTime(event.currentTarget.currentTime)} onPlay={() => setPlaying(true)} onPause={() => setPlaying(false)} onPlaying={() => setWaiting(false)} onWaiting={() => setWaiting(true)} onCanPlay={() => setWaiting(false)} onEnded={() => {
    setPlaying(false);
    setControlsVisible(true);
  }} onVolumeChange={event => setMuted(event.currentTarget.muted)} />

        {enhanced && <>
            {!playing && (currentTime <= 0.2 || replaying) && <button type="button" className="hf-docs-video-hero-play" onClick={togglePlayback} aria-label={replaying ? "Replay video" : "Play video"}>
                <span className="hf-docs-video-hero-icon" aria-hidden="true">
                  <svg viewBox="0 0 24 24">
                    <path d="M8 5.5v13l10-6.5z" />
                  </svg>
                </span>
              </button>}

            {waiting && playing && <span className="hf-docs-video-spinner" aria-label="Loading" />}

            <div className="hf-docs-video-controls" data-visible={controlsVisible ? "true" : "false"}>
              <div className="hf-docs-video-scrub-preview" data-visible={previewing ? "true" : "false"} style={{
    "--hf-video-preview-x": `${previewPosition}%`
  }} aria-hidden="true">
                <span>{formatTime(previewTime)}</span>
              </div>

              <input className="hf-docs-video-progress" type="range" min="0" max={duration || 0} step="0.01" value={Math.min(currentTime, duration || 0)} aria-label="Video progress" aria-valuetext={`${formatTime(currentTime)} of ${formatTime(duration)}`} onChange={seek} onPointerEnter={updateScrubPreview} onPointerMove={event => updateScrubPreview(event, scrubbing || event.buttons === 1)} onPointerDown={event => {
    setScrubbing(true);
    event.currentTarget.setPointerCapture?.(event.pointerId);
    updateScrubPreview(event, true);
  }} onPointerUp={event => {
    setScrubbing(false);
    if (event.pointerType !== "mouse") setPreviewing(false);
  }} onPointerCancel={() => {
    setScrubbing(false);
    setPreviewing(false);
  }} onPointerLeave={() => {
    if (!scrubbing) setPreviewing(false);
  }} style={{
    "--hf-video-progress": `${progress}%`
  }} />

              <div className="hf-docs-video-control-row">
                <button type="button" className="hf-docs-video-control" onClick={togglePlayback} aria-label={playing ? "Pause video" : "Play video"}>
                  {playing ? <svg viewBox="0 0 24 24" aria-hidden="true">
                      <path d="M7 5h4v14H7zm6 0h4v14h-4z" />
                    </svg> : <svg viewBox="0 0 24 24" aria-hidden="true">
                      <path d="M8 5.5v13l10-6.5z" />
                    </svg>}
                </button>

                <button type="button" className="hf-docs-video-control" onClick={toggleMute} aria-label={muted ? "Unmute video" : "Mute video"}>
                  {muted ? <svg viewBox="0 0 24 24" aria-hidden="true">
                      <path d="M4 9v6h4l5 4V5L8 9zm11.5 1.1 1.4-1.4 1.6 1.6 1.6-1.6 1.4 1.4-1.6 1.6 1.6 1.6-1.4 1.4-1.6-1.6-1.6 1.6-1.4-1.4 1.6-1.6z" />
                    </svg> : <svg viewBox="0 0 24 24" aria-hidden="true">
                      <path d="M4 9v6h4l5 4V5L8 9zm11 1.2v3.6c1-.5 1.7-1.5 1.7-2.8S16 10.7 15 10.2zm0-4v2.1c2.2.6 3.7 2.5 3.7 4.7s-1.5 4.1-3.7 4.7v2.1c3.3-.7 5.7-3.5 5.7-6.8S18.3 6.9 15 6.2z" />
                    </svg>}
                </button>

                <span className="hf-docs-video-time" aria-hidden="true">
                  {formatTime(currentTime)} <span>/</span> {formatTime(duration)}
                </span>

                <span className="hf-docs-video-spacer" />

                <button type="button" className="hf-docs-video-rate" onClick={cyclePlaybackRate} aria-label={`Playback speed ${playbackRate} times`}>
                  {playbackRate}×
                </button>

                {fullscreenSupported && <button type="button" className="hf-docs-video-control" onClick={toggleFullscreen} aria-label={fullscreen ? "Exit fullscreen" : "Enter fullscreen"}>
                    {fullscreen ? <svg viewBox="0 0 24 24" aria-hidden="true">
                        <path d="M8 3H6v3H3v2h5zm8 0v5h5V6h-3V3zM3 16v2h3v3h2v-5zm13 0v5h2v-3h3v-2z" />
                      </svg> : <svg viewBox="0 0 24 24" aria-hidden="true">
                        <path d="M3 8h2V5h3V3H3zm13-5v2h3v3h2V3zM5 16H3v5h5v-2H5zm14 3h-3v2h5v-5h-2z" />
                      </svg>}
                  </button>}
              </div>
            </div>
          </>}
      </div>

    </div>;
};

Give each audio layer one job. Add another layer only when it helps the viewer
understand or feel the video.

| Layer         | Main job                                            |
| ------------- | --------------------------------------------------- |
| Voiceover     | Carry the explanation or story                      |
| Source audio  | Preserve speech or sound from existing footage      |
| Music         | Shape pace, tone, and structure                     |
| Sound effects | Reinforce a specific action or transition           |
| Captions      | Make spoken words readable and searchable on screen |

<Frame caption="Play with sound. The same real HyperFrames scene first lets music compete with the line, then gives the voice room while keeping a stable caption rail.">
  <DocsVideo title="A comparison of an obstructed and a clear narration mix" poster="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/audio-mix-proof-v1.jpg" src="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/audio-mix-proof-v1.mp4" />
</Frame>

## Create a voiceover

Give the agent the approved wording and useful voice direction:

```text theme={null}
Generate the approved SCRIPT.md as a warm, direct voiceover.
Natural pace, no announcer energy. Keep the product-name pronunciation exact.
```

The project can keep the script, audio, and word-level transcript separately.
That lets you regenerate the voice without discarding the timing and caption
work around it.

Listen before building the final edit. Fix wording, pronunciation, or delivery
in the script or voice direction rather than cutting around a bad read.

## Transcribe recorded speech

Transcription creates timed words from an audio or video file. Start with the
automatic engine: it uses Parakeet when installed and falls back to Whisper.

```bash theme={null}
npx hyperframes transcribe interview.mp4
```

Pass the spoken language when you know it. This filters non-target speech and
lets the Whisper fallback choose a multilingual model when needed.

```bash theme={null}
npx hyperframes transcribe interview.mp4 --language es
```

For difficult English audio, force the larger English Whisper model. For an
unknown language, use multilingual `large-v3` and let Whisper detect it.

```bash theme={null}
npx hyperframes transcribe interview.mp4 --engine whisper --model medium.en
npx hyperframes transcribe interview.mp4 --engine whisper --model large-v3
```

Larger models take longer and do not remove the need to read the result.

The command can also import an existing `.srt`, `.vtt`, or supported transcript
JSON file:

```bash theme={null}
npx hyperframes transcribe subtitles.srt
```

## Turn the transcript into captions

1. Read the complete transcript.
2. Correct names, product terms, numbers, punctuation, and obvious recognition
   errors.
3. Group words into short phrases that break on meaning.
4. Open [Captions in Studio](/studio/captions) to inspect the rhythm and adjust
   placement, scale, or rotation. Make durable wording, timing, style, and
   animation changes in the caption source or ask the agent to update it.
5. Watch once with sound for synchronization and once muted for readability.

Captions should follow what was said. They should not cover a face, product
control, or another important visual. Use emphasis on the few words that carry
the point instead of making every word compete.

For an existing talking-head clip, use [Captions or
recuts](/guides/captions-and-recuts) to choose between plain captions, designed
graphic overlays, and an actual change to the spoken edit.

## Mix for understanding

* Keep voice clear above music.
* Duck music under important speech instead of reducing the whole track
  equally.
* Use sound effects for meaningful events, not every movement.
* Avoid cutting words, breaths, or reverb tails accidentally at scene
  boundaries.
* Let a deliberate silence remain silent.
* Listen on ordinary headphones and laptop speakers.

When narration drives the project, time visual changes to its real transcript
rather than estimated scene lengths. When music drives the project, use the
[music-video workflow](/guides/music-to-video) and its analyzed structure.

## Review the complete sound pass

* The correct voice and source recordings are used.
* Names, claims, and captions are accurate.
* Speech stays clear through the loudest musical section.
* Effects arrive with the action they support.
* The opening does not surprise the listener with excessive volume.
* Music and ambience finish intentionally instead of stopping at the file edge.

Render a review file and listen without watching once. Audio problems are often
easier to notice when the visuals are not competing for attention.

## Related topics

* [Add captions or repackage talking-head footage](/guides/captions-and-recuts)
* [Edit captions in Studio](/studio/captions)
* [Finish, render, and share](/guides/export-and-share)


## Related topics

- [Create a music-driven video](/guides/music-to-video.md)
- [Add captions or repackage talking-head footage](/guides/captions-and-recuts.md)
- [Media and audio](/prompting/media-and-audio.md)