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Overview

RivaSTTService provides real-time speech-to-text capabilities using NVIDIA’s Riva Parakeet model. It supports interim results and configurable recognition parameters for enhanced accuracy. RivaSegmentedSTTService provides speech-to-text capabilities via NVIDIA’s Riva Canary model.

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Installation

To use RivaSTTService or RivaSegmentedSTTService, install the required dependencies:

pip install "pipecat-ai[riva]"

You’ll also need to set up your NVIDIA API key as an environment variable: NVIDIA_API_KEY.

You can obtain an NVIDIA API key by signing up through NVIDIA’s developer portal.

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RivaSTTService

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Configuration

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api_key
str
required

Your NVIDIA API key

​
server
str
default:"grpc.nvcf.nvidia.com:443"

NVIDIA Riva server address

​
model_function_map
Mapping [str, str]

A mapping of the NVIDIA function identifier for the STT service with the model name.

​
sample_rate
int
default:"None"

Audio sample rate in Hz

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params
InputParams
default:"InputParams()"

Additional configuration parameters

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InputParams

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language
Language
default:"Language.EN_US"

The language for speech recognition

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Input

The service processes audio frames containing:

  • Raw PCM audio data
  • 16-bit depth
  • Single channel (mono)

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Output Frames

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TranscriptionFrame

Generated for final transcriptions, containing:

​
text
string

Transcribed text

​
user_id
string

User identifier

​
timestamp
string

ISO 8601 formatted timestamp

​
language
Language

Language used for transcription

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InterimTranscriptionFrame

Generated during ongoing speech, containing same fields as TranscriptionFrame but with preliminary results.

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RivaSegmentedSTTService

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Configuration

​
api_key
str
required

Your NVIDIA API key

​
server
str
default:"grpc.nvcf.nvidia.com:443"

NVIDIA Riva server address

​
model_function_map
Mapping [str, str]

A mapping of the NVIDIA function identifier for the STT service with the model name.

​
sample_rate
int
default:"None"

Audio sample rate in Hz

​
params
InputParams
default:"InputParams()"

Additional configuration parameters

​
InputParams

​
language
Language
default:"Language.EN_US"

The language for speech recognition

​
Input

The service processes audio frames containing:

  • Raw audio bytes in WAV format

​
Output Frames

​
TranscriptionFrame

Generated for final transcriptions, containing:

​
text
string

Transcribed text

​
user_id
string

User identifier

​
timestamp
string

ISO 8601 formatted timestamp

​
language
Language

Language used for transcription

​
InterimTranscriptionFrame

Generated during ongoing speech, containing same fields as TranscriptionFrame but with preliminary results.

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Methods

See the STT base class methods for additional functionality.

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Models

ModelPipecat ClassModel Card Link
parakeet-ctc-1.1b-asrRivaSTTServiceNVIDIA Model Card
canary-1b-asrRivaSegmentedSTTServiceNVIDIA Model Card

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Usage Examples

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RivaSTTService

from pipecat.services.riva.stt import RivaSTTService
from pipecat.transcriptions.language import Language

# Configure service
stt = RivaSTTService(
    api_key="your-nvidia-api-key",
    params=RivaSTTService.InputParams(
        language=Language.EN_US
    )
)

# Use in pipeline
pipeline = Pipeline([
    transport.input(),
    stt,
    llm,
    ...
])

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RivaSegmentedSTTService

from pipecat.services.riva.stt import RivaSegmentedSTTService
from pipecat.transcriptions.language import Language

# Configure service
stt = RivaSegmentedSTTService(
    api_key="your-nvidia-api-key",
    params=RivaSegmentedSTTService.InputParams(
        language=Language.EN_US
    )
)

# Use in pipeline
pipeline = Pipeline([
    transport.input(),
    stt,
    llm,
    ...
])

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Language Support

Riva model parakeet-ctc-1.1b-asr (default) primarily supports English with various regional accents:

Language CodeDescriptionService Codes
Language.EN_USEnglish (US)en-US

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Frame Flow

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Advanced Configuration

The service supports several advanced configuration options that can be adjusted:

​
_profanity_filter
bool
default:"False"

Filter profanity from transcription

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_automatic_punctuation
bool
default:"False"

Automatically add punctuation

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_no_verbatim_transcripts
bool
default:"False"

Whether to disable verbatim transcripts

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_boosted_lm_words
list
default:"None"

List of words to boost in the language model

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_boosted_lm_score
float
default:"4.0"

Score applied to boosted words

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Example with Advanced Configuration

# Configure service with advanced parameters
stt = RivaSTTService(
    api_key="your-nvidia-api-key",
    params=RivaSTTService.InputParams(
        language=Language.EN_US
    )
)

# Configure advanced options
stt._profanity_filter = True
stt._automatic_punctuation = True
stt._boosted_lm_words = ["PipeCat", "AI", "speech"]

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Notes

  • Uses NVIDIA’s Riva AI Services platform
  • Handles streaming audio input
  • Provides real-time transcription results
  • Manages connection lifecycle
  • Uses asyncio for asynchronous processing
  • Automatically cleans up resources on stop/cancel