About NVIDIA TTS NIM Microservice#

The NVIDIA Text-to-Speech (TTS) NIM microservice synthesizes natural-sounding speech from text. It packages pre-trained NeMo models with the full NVIDIA inference stack into self-contained containers that handle model download, optimization, and serving.

The NVIDIA TTS NIM microservice supports two synthesis modes:

  • Offline: Generates the complete audio and returns it in a single response. Simpler to use, but subject to a 4 MB gRPC message size limit.

  • Streaming: Returns audio in chunks as they are generated. Provides lower time-to-first-audio and handles arbitrarily long text.

Available Models#

Model

Languages

Modes

Key Capability

Magpie TTS Multilingual

English, Spanish, French, German, Mandarin, Vietnamese, Italian, Hindi, Japanese, Korean, Arabic, Portuguese

Streaming + Offline

Multi-voice, multi-language synthesis

Magpie TTS Zeroshot

English, Spanish, French, German, Mandarin, Vietnamese, Italian, Hindi, Japanese, Arabic, Portuguese, Korean

Streaming + Offline

Multilingual voice cloning from a reference audio sample

Chatterbox TTS Multilingual

23 languages incl. Arabic, English, Spanish, French, German, Hindi, Japanese, Korean, Mandarin, Portuguese, Russian

Streaming + Offline

Emotion exaggeration

Note

Magpie TTS Zeroshot requires access approval. Request access through this form.

For GPU requirements and all model profiles, refer to the TTS support matrix.

Key Capabilities#

Voice Selection and Emotional Styles#

Each TTS model includes multiple voices organized by language and locale. The Magpie Multilingual model provides voices with optional emotional style variants, such as Magpie-Multilingual.EN-US.Aria.Angry and Magpie-Multilingual.FR-FR.Pascal.Calm. Refer to Voices and Emotional Styles for the naming convention and available emotions.

Voice Cloning#

The Magpie TTS Zeroshot model clones a voice from a short reference audio recording (3–10 seconds, 16-bit mono WAV at 22.05 kHz or higher). Refer to Voice Cloning for audio prompt preparation, quality tuning, and examples.

Batch Synthesis#

The WebSocket realtime client supports synthesizing speech from text files and processing multiple lines in parallel for higher throughput. Refer to Batch Synthesis for details.

SSML Customization#

The TTS NIM microservice supports a subset of Speech Synthesis Markup Language (SSML) for controlling phoneme pronunciation. Refer to Customizing TTS Models for details and examples.

Custom Pronunciation#

Define a text-based dictionary that maps words to IPA phonetic representations. The TTS model applies these custom pronunciations during synthesis. Refer to Phoneme Support for supported phonemes.

Next Steps#