Customization¶

Customize voice, video, and output settings.

Voice Settings¶

Default Voice¶

Set via command line:

vac \
  --input slides.md \
  --voice pNInz6obpgDQGcFmaJgB \
  --output video.mp4

ElevenLabs Voices¶

Popular voices:

Voice ID	Name	Description
`pNInz6obpgDQGcFmaJgB`	Adam	Clear, professional male
`21m00Tcm4TlvDq8ikWAM`	Rachel	Warm, natural female
`onwK4e9ZLuTAKqWW03F9`	Daniel	British male
`XrExE9yKIg1WjnnlVkGX`	Matilda	American female

Voice Settings in transcript.json¶

Fine-tune voice parameters:

{
  "defaultVoice": {
    "provider": "elevenlabs",
    "voiceId": "pNInz6obpgDQGcFmaJgB",
    "voiceName": "Adam",
    "model": "eleven_multilingual_v2",
    "stability": 0.5,
    "similarityBoost": 0.75,
    "style": 0.2
  }
}

Parameter	Range	Description
`stability`	0.0 - 1.0	Voice consistency (higher = more stable)
`similarityBoost`	0.0 - 1.0	Voice similarity (higher = closer to original)
`style`	0.0 - 1.0	Style exaggeration (higher = more expressive)

Venue Presets¶

Optimize for different platforms:

Venue	Stability	Similarity	Style	Use Case
YouTube	0.45	0.8	0.2	Sustained attention
Udemy	0.5	0.75	0.0	Clear, consistent
Coursera	0.7	0.85	0.2	Academic, engaging
TikTok	0.3	0.85	0.45	Energetic, immediate

Set in transcript.json:

{
  "metadata": {
    "defaultVenue": "youtube"
  }
}

Video Settings¶

Resolution¶

# Full HD (default)
--width 1920 --height 1080

# 720p
--width 1280 --height 720

# 4K UHD
--width 3840 --height 2160

Frame Rate¶

--fps 24  # Cinematic
--fps 30  # Standard (default)
--fps 60  # Smooth

Transitions¶

--transition 0.5  # 0.5 second crossfade
--transition 1.0  # 1 second crossfade
--transition 0    # No transitions (default)

Screen Recording¶

macOS Screen Device¶

Auto-detected, but can be overridden:

# List available devices
ffmpeg -f avfoundation -list_devices true -i ""

# Use specific device
vac --input slides.md --output video.mp4 \
  --screen-device "4:none"

Working Directory¶

Customize temp file location:

vac --input slides.md --output video.mp4 \
  --workdir /path/to/workdir

Files created:

workdir/
├── audio/slide_*.mp3
├── video/slide_*.mp4
└── html/presentation.html