---
title: "Use voice, music, sound, and captions"
sidebarTitle: "Voice, sound, and captions"
description: "Build an understandable audio mix, transcribe real speech, and turn it into readable captions."
---

import { DocsVideo } from "/snippets/docs-video.jsx";

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 |


<DocsVideo
  title="Narration, music ducking under it, and effects landing on the beat"
  src="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/voice-audio-demo-v2.mp4"
  poster="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/voice-audio-demo-v2.jpg"
/>

Turn the sound on for this one — the audio is the subject. You can watch the
music duck as narration arrives and see each effect land against the waveform.

## Create a voiceover

Give the agent the approved wording and useful voice direction:

```text
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
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
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
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
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. A [voiceover carve](/studio/voiceover-carve)
  does this properly: it takes only the bands the voice occupies out of the
  music, so the bed keeps its low end and its top instead of going limp for the
  whole voiceover.
- 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)