Voice.ai Creator Voiceover Pipeline

This skill follows the Agent Skills specification.

Turn any script into a publish-ready voiceover — complete with numbered segments, a stitched master, YouTube chapters, SRT captions, and a beautiful review page. Optionally, replace the audio track on an existing video.

Built for creators who want studio-quality voiceovers without the studio. Powered by Voice.ai.

When to use this skill

The one-command workflow

Have a script and a video? Turn them into a finished video with AI voiceover in one shot:

node voiceai-vo.cjs build \
  --input my-script.md \
  --voice oliver \
  --title "My Video" \
  --video ./my-recording.mp4 \
  --mux

This renders the voiceover, stitches the master audio, and drops it onto your video — all in one command. Output:

• out/my-video/muxed.mp4 — your video with the new voiceover
• out/my-video/master.wav — the standalone audio
• out/my-video/review.html — listen and review each segment
• out/my-video/chapters.txt — YouTube-ready chapter timestamps
• out/my-video/captions.srt — SRT captions

Use --sync pad if the audio is shorter than the video, or --sync trim to cut it to match.

Requirements

• Node.js 20+ — runtime (no npm install needed — the CLI is a single bundled file)
• VOICE_AI_API_KEY — set as environment variable or in a .env file in the skill root. Get a key at voice.ai/dashboard.
• ffmpeg (optional) — needed for master stitching, MP3 encoding, loudness normalization, and video muxing. The pipeline still produces individual segments, the review page, chapters, and captions without it.

Configuration

The skill reads VOICE_AI_API_KEY from (in order):

1. Environment variable VOICE_AI_API_KEY
2. Environment variable VOICEAI_API_KEY (alternate)
3. .env file in the skill root

echo 'VOICE_AI_API_KEY=your-key-here' > .env

Use --mock on any command to run the full pipeline without an API key (produces placeholder audio).

Commands

build — Generate a voiceover from a script

node voiceai-vo.cjs build \
  --input <script.md or script.txt> \
  --voice <voice-alias-or-uuid> \
  --title "My Project" \
  [--template youtube|podcast|shortform] \
  [--language en] \
  [--video input.mp4 --mux --sync shortest] \
  [--force] [--mock]

What it does:

1. Reads the script and splits it into segments (by ## headings for .md, or by sentence boundaries for .txt)
2. Optionally prepends/appends template intro/outro segments
3. Renders each segment via Voice.ai TTS as a numbered WAV file
4. Stitches a master audio file (if ffmpeg is available)
5. Generates chapters, captions, a review page, and metadata files
6. Optionally muxes the voiceover into an existing video

Full options:

replace-audio — Swap the audio track on a video

node voiceai-vo.cjs replace-audio \
  --video ./input.mp4 \
  --audio ./out/my-project/master.wav \
  [--out ./out/my-project/muxed.mp4] \
  [--sync shortest|pad|trim]

Requires ffmpeg. If not installed, generates helper shell/PowerShell scripts instead.

Video stream is copied without re-encoding (-c:v copy). Audio is encoded as AAC. A mux report is saved alongside the output.

Privacy: Video processing is entirely local. Only script text is sent to Voice.ai for TTS.

voices — List available voices

node voiceai-vo.cjs voices [--limit 20] [--query "deep"] [--mock]

Available voices

Use short aliases or full UUIDs with --voice:

The voices command also returns any additional voices available on the API. Voice list is cached for 10 minutes.

Build outputs

After a build, the output directory contains:

out/<title-slug>/
  segments/           # Numbered WAV files (001-intro.wav, 002-section.wav, …)
  master.wav          # Stitched audio (requires ffmpeg)
  master.mp3          # MP3 encode (requires ffmpeg)
  manifest.json       # Build metadata: voice, template, segment list, hashes
  timeline.json       # Segment durations and start times
  review.html         # Interactive review page with audio players
  chapters.txt        # YouTube-friendly chapter timestamps
  captions.srt        # SRT captions using segment boundaries
  description.txt     # YouTube description with chapters + Voice.ai credit

review.html

A standalone HTML page with:

• Master audio player (if stitched)
• Individual segment players with titles and durations
• Collapsible script text for each segment
• Regeneration command hints

Templates

Templates auto-inject intro/outro segments around the script content:

Edit the files in templates/ to customize the intro/outro text.

Caching

Segments are cached by a hash of: text content + voice ID + language.

• Unchanged segments are skipped on rebuild — fast iteration
• Modified segments are re-rendered automatically
• Use --force to re-render everything
• Cache manifest is stored in segments/.cache.json

Multilingual support

Voice.ai supports 11 languages. Use --language <code> to switch:

en, es, fr, de, it, pt, pl, ru, nl, sv, ca

The pipeline auto-selects the multilingual TTS model for non-English languages.

Troubleshooting

See references/TROUBLESHOOTING.md for more.

References

• Agent Skills Specification
• Voice.ai
• references/VOICEAI_API.md — API endpoints, audio formats, models
• references/TROUBLESHOOTING.md — Common issues and fixes