Text to speech

Install the belt CLI skill: npx skills add belt-sh/cli

Text-to-Speech

Convert text to natural speech via inference.sh CLI.

Quick Start

Requires inference.sh CLI (belt). Install instructions

belt login

# Generate speech
belt app run infsh/kokoro-tts --input '{"text": "Hello, welcome to our product demo."}'

Available Models

Model	App ID	Best For
Inworld TTS-2	inworld/text-to-speech-2	100+ languages, emotion steering with [brackets], delivery modes
Inworld TTS 1.5 Max	inworld/text-to-speech-1-5-max	Low latency (<200ms), 15 languages
Inworld TTS 1.5 Mini	inworld/text-to-speech-1-5-mini	Ultra-low latency (~120ms), 15 languages
ElevenLabs TTS	elevenlabs/tts	Premium quality, 22+ voices, 32 languages
DIA TTS	infsh/dia-tts	Conversational, expressive
Kokoro TTS	infsh/kokoro-tts	Fast, natural
Chatterbox	infsh/chatterbox	General purpose
Higgs Audio	infsh/higgs-audio	Emotional control
VibeVoice	infsh/vibevoice	Podcasts, long-form

Browse All Audio Apps

belt app list --category audio

Examples

Basic Text-to-Speech

belt app run infsh/kokoro-tts --input '{"text": "Welcome to our tutorial."}'

Inworld TTS-2 — Emotion Steering

Inworld TTS-2 supports natural-language steering with [brackets] — control emotion, volume, speed, and non-verbals inline with text:

belt app run inworld/text-to-speech-2 --input '{
  "text": "I have some [exciting] news to share with you! [pause] We just hit one million users. [laugh]",
  "voice_id": "Sarah",
  "delivery_mode": "CREATIVE"
}'

Delivery modes: STABLE (consistent), BALANCED (natural, default), CREATIVE (expressive).

Built-in voices (271+ across 15 languages): Sarah, Alex, Ashley, Dennis, Hana, Blake, Luna, Clive, and many more. Browse all voices in the Inworld TTS Playground or list programmatically via GET https://api.inworld.ai/voices/v1/voices.

Inworld TTS 1.5 — Low Latency

For real-time applications where speed matters:

# Max quality at low latency (<200ms)
belt app run inworld/text-to-speech-1-5-max --input '{
  "text": "Welcome back! How can I help you today?",
  "voice_id": "Ashley"
}'

# Ultra-low latency (~120ms) for conversational AI
belt app run inworld/text-to-speech-1-5-mini --input '{
  "text": "Sure, let me look that up for you.",
  "voice_id": "Dennis"
}'

Conversational TTS with DIA

belt app sample infsh/dia-tts --save input.json

# Edit input.json:
# {
#   "text": "Hey! How are you doing today? I'm really excited to share this with you.",
#   "voice": "conversational"
# }

belt app run infsh/dia-tts --input input.json

Long-form Audio (Podcasts)

belt app sample infsh/vibevoice --save input.json

# Edit input.json with your podcast script
belt app run infsh/vibevoice --input input.json

Expressive Speech with Higgs

belt app sample infsh/higgs-audio --save input.json

# {
#   "text": "This is absolutely incredible!",
#   "emotion": "excited"
# }

belt app run infsh/higgs-audio --input input.json

Use Cases

• Voiceovers: Product demos, explainer videos
• Audiobooks: Convert text to spoken word
• Podcasts: Generate podcast episodes
• Accessibility: Make content accessible
• IVR: Phone system voice prompts
• Video Narration: Add narration to videos
• Gaming / NPCs: Character voices with emotion steering (Inworld TTS-2)
• Conversational AI: Ultra-low latency responses (Inworld TTS 1.5 Mini)
• Avatar / UGC Videos: Generate speech for talking head avatars

Combine with Video

The easiest way to create a talking head video is P-Video-Avatar with built-in TTS — no separate audio step:

belt app run pruna/p-video-avatar --input '{
  "image": "https://portrait.jpg",
  "voice_script": "Your script here",
  "voice": "Zephyr (Female)"
}'

For models without built-in TTS (OmniHuman, PixVerse), generate speech first:

# 1. Generate speech with Inworld TTS-2 (emotion steering)
belt app run inworld/text-to-speech-2 --input '{
  "text": "[friendly] Your script here. [excited] This is the best part!",
  "voice_id": "Sarah",
  "delivery_mode": "CREATIVE"
}' > speech.json

# 2. Use the audio URL with OmniHuman for avatar video
belt app run bytedance/omnihuman-1-5 --input '{
  "image_url": "https://portrait.jpg",
  "audio_url": "<audio-url-from-step-1>"
}'

Related Skills

# ElevenLabs TTS (premium, 22+ voices)
npx skills add inference-sh/skills@elevenlabs-tts

# ElevenLabs dialogue (multi-speaker)
npx skills add inference-sh/skills@elevenlabs-dialogue

# Full platform skill (all 250+ apps)
npx skills add inference-sh/skills@infsh-cli

# AI avatars (combine TTS with talking heads)
npx skills add inference-sh/skills@ai-avatar-video

# AI music generation
npx skills add inference-sh/skills@ai-music-generation

# Speech-to-text (transcription)
npx skills add inference-sh/skills@speech-to-text

# Video generation
npx skills add inference-sh/skills@ai-video-generation

Browse all apps: belt app list

Documentation

• Running Apps - How to run apps via CLI
• Audio Transcription Example - Audio processing workflows
• Apps Overview - Understanding the app ecosystem