audio-generation

Documents

Guide to audio generation and understanding in MassGen. Covers text-to-speech, music, sound effects, and audio understanding across ElevenLabs and OpenAI backends.

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Audio Generation

Generate audio using generate_media with mode="audio". Supports speech (TTS), music, and sound effects. ElevenLabs is preferred when available, with OpenAI as fallback.

Quick Start

# Text-to-speech (auto-selects ElevenLabs if key available)
generate_media(prompt="Hello, welcome to our presentation!", mode="audio")

# With specific voice
generate_media(prompt="Hello!", mode="audio", voice="Rachel")

# Music generation (ElevenLabs only)
generate_media(prompt="Upbeat jazz piano with soft drums", mode="audio",
               audio_type="music", duration=30)

# Sound effects (ElevenLabs only)
generate_media(prompt="Thunder rolling across a mountain valley", mode="audio",
               audio_type="sound_effect", duration=5)

Audio Types

Type	Backends	Description
`"speech"` (default)	ElevenLabs, OpenAI	Text-to-speech with voice selection
`"music"`	ElevenLabs only	Music generation from text prompt
`"sound_effect"`	ElevenLabs only	Sound effect generation
`"voice_conversion"`	ElevenLabs only	Change voice of existing audio (speech-to-speech)
`"audio_isolation"`	ElevenLabs only	Remove background noise, isolate vocals
`"voice_design"`	ElevenLabs only	Create a new synthetic voice from text description
`"voice_clone"`	ElevenLabs only	Clone a voice from audio samples
`"dubbing"`	ElevenLabs only	Translate and dub audio to another language

Backend Comparison

Backend	Default Model	Supports	API Key
ElevenLabs (priority 1)	`eleven_multilingual_v2`	Speech, music, SFX	`ELEVENLABS_API_KEY`
OpenAI (priority 2)	`gpt-4o-mini-tts`	Speech only	`OPENAI_API_KEY`

If ElevenLabs TTS fails, the system automatically falls back to OpenAI TTS.

Key Parameters

Parameter	Description	Example
`prompt`	Text to speak (speech) or description (music/SFX)	`"Hello world!"`
`voice`	Voice name or ID	`"Rachel"`, `"nova"`, `"alloy"`
`audio_type`	Type of audio	`"speech"`, `"music"`, `"sound_effect"`
`duration`	Length in seconds (music/SFX only)	`30`
`instructions`	Speaking style (OpenAI `gpt-4o-mini-tts` only)	`"warm, reflective tone"`
`audio_format`	Output format	`"mp3"`, `"wav"`, `"opus"`

Voice Quick Reference

ElevenLabs (top voices):

Voice	Character
Rachel	Warm, conversational female
Sarah	Clear, professional female
Josh	Friendly male
Adam	Deep, authoritative male
Emily	Bright, energetic female

OpenAI voices: alloy, echo, fable, onyx, nova, shimmer, coral, sage

Important: prompt vs instructions

For speech, prompt is the literal text to speak. Style guidance goes in instructions:

# CORRECT: prompt = text to speak, instructions = how to speak it
generate_media(
    prompt="Welcome to the annual report presentation.",
    mode="audio",
    voice="alloy",
    instructions="warm, reflective tone with measured pacing",
    backend_type="openai"
)

# WRONG: Don't put style instructions in prompt
generate_media(prompt="Say this warmly: Welcome...", mode="audio")  # Bad!

instructions only works with OpenAI gpt-4o-mini-tts. ElevenLabs uses voice selection for tone.

Audio Understanding

Use read_media (not generate_media) to analyze existing audio:

read_media(path="recording.mp3", prompt="Transcribe and summarize this audio")

Need More Control?

Full ElevenLabs voice catalog (28+ voices): See references/voices.md
Music and sound effects details: See references/music_and_sfx.md
Advanced audio capabilities (voice conversion, cloning, isolation, dubbing): See references/advanced.md