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Overview

NvidiaTTSService provides high-quality text-to-speech synthesis through NVIDIA Riva’s cloud-based AI models accessible via gRPC API. The service offers multilingual support, configurable quality settings, and streaming audio generation optimized for real-time applications.

NVIDIA Riva TTS API Reference

Pipecat’s API methods for NVIDIA Riva TTS integration

Example Implementation

Complete example with Riva NIM

NVIDIA Riva Documentation

Official NVIDIA Riva TTS documentation

NVIDIA Developer Portal

Access API keys and Riva services

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Installation

To use NVIDIA Riva services, install the required dependencies: 
pip install "pipecat-ai[nvidia]"

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Prerequisites

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NVIDIA Riva Setup

Before using Riva TTS services, you need:
  1. NVIDIA Developer Account: Sign up at NVIDIA Developer Portal
  2. API Key: Generate an NVIDIA API key for Riva services
  3. Riva Access: Ensure access to NVIDIA Riva TTS services

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Required Environment Variables

  • NVIDIA_API_KEY: Your NVIDIA API key for authentication

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Configuration

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NvidiaTTSService

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api_key
str
required
NVIDIA API key for authentication.
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server
str
default:"grpc.nvcf.nvidia.com:443"
gRPC server endpoint.
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voice_id
str
default:"Magpie-Multilingual.EN-US.Aria"
Voice model identifier.
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sample_rate
int
default:"None"
Audio sample rate in Hz. When None, uses the pipeline’s configured sample rate.
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model_function_map
dict
Dictionary containing function_id and model_name for the TTS model.
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use_ssl
bool
default:"True"
Whether to use SSL for the NVIDIA Riva server connection.
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params
InputParams
default:"None"
Runtime-configurable synthesis settings. See InputParams below.

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InputParams

ParameterTypeDefaultDescription
languageLanguageLanguage.EN_USLanguage code for synthesis.
qualityint20Audio quality setting (0-100).

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Usage

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Basic Setup

from pipecat.services.nvidia import NvidiaTTSService

tts = NvidiaTTSService(
    api_key=os.getenv("NVIDIA_API_KEY"),
)

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With Custom Voice and Quality

from pipecat.services.nvidia import NvidiaTTSService
from pipecat.transcriptions.language import Language

tts = NvidiaTTSService(
    api_key=os.getenv("NVIDIA_API_KEY"),
    voice_id="Magpie-Multilingual.EN-US.Aria",
    model_function_map={
        "function_id": "877104f7-e885-42b9-8de8-f6e4c6303969",
        "model_name": "magpie-tts-multilingual",
    },
    params=NvidiaTTSService.InputParams(
        language=Language.EN_US,
        quality=40,
    ),
)

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Notes

  • gRPC-based: NVIDIA Riva uses gRPC (not HTTP or WebSocket) for communication with the TTS service.
  • Model cannot be changed after initialization: The model and function ID must be set during construction via model_function_map. Calling set_model() after initialization will log a warning and have no effect.
  • SSL enabled by default: The service connects to NVIDIA’s cloud endpoint with SSL. Set use_ssl=False only for local or custom Riva deployments.
  • Blocking gRPC calls: Audio generation uses asyncio.to_thread to avoid blocking the event loop, since the underlying Riva client uses synchronous gRPC calls.