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Overview

AWSTranscribeSTTService provides real-time speech-to-text capabilities using Amazon Transcribe’s WebSocket API. It supports interim results, adjustable quality levels, and can handle continuous audio streams.

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Installation

To use AWSTranscribeSTTService, install the required dependencies:

pip install "pipecat-ai[aws]"

You’ll also need to set up your AWS credentials as environment variables:

  • AWS_ACCESS_KEY_ID
  • AWS_SECRET_ACCESS_KEY
  • AWS_SESSION_TOKEN (if using temporary credentials)
  • AWS_REGION (defaults to “us-east-1”)

You can obtain AWS credentials by setting up an IAM user with access to Amazon Transcribe in your AWS account.

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Configuration

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Constructor Parameters

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api_key
str

Your AWS secret access key (can also use environment variable)

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aws_access_key_id
str

Your AWS access key ID (can also use environment variable)

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aws_session_token
str

Your AWS session token for temporary credentials (can also use environment variable)

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region
str
default:"us-east-1"

AWS region to use for Transcribe service

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sample_rate
int
default:"16000"

Audio sample rate in Hz (only 8000 Hz or 16000 Hz are supported)

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language
Language
default:"Language.EN"

Language for transcription

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Default Settings

{
    "sample_rate": 16000,
    "language": Language.EN,
    "media_encoding": "linear16",  # AWS expects raw PCM
    "number_of_channels": 1,
    "show_speaker_label": False,
    "enable_channel_identification": False
}

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Input

The service processes InputAudioRawFrame instances containing:

  • Raw PCM audio data
  • 16-bit depth
  • 8kHz or 16kHz sample rate (will convert to 16kHz if another rate is provided)
  • Single channel (mono)

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Output Frames

The service produces two types of frames during transcription:

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TranscriptionFrame

Generated for final transcriptions, containing:

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text
string

Transcribed text

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user_id
string

User identifier

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timestamp
string

ISO 8601 formatted timestamp

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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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Methods

See the STT base class methods for additional functionality.

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Language Setting

await service.set_language(Language.FR)

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Usage Example

from pipecat.services.aws.stt import AWSTranscribeSTTService

# Configure service using environment variables for credentials
stt = AWSTranscribeSTTService(
    region="us-west-2",
    sample_rate=16000,
    language=Language.EN
)

# Or provide credentials directly
stt = AWSTranscribeSTTService(
    aws_access_key_id="YOUR_ACCESS_KEY_ID",
    api_key="YOUR_SECRET_ACCESS_KEY",
    region="us-west-2",
    sample_rate=16000,
    language=Language.EN
)

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

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Language Support

AWS Transcribe STT supports the following languages:

Language CodeDescriptionService Codes
Language.ENEnglish (US)en-US
Language.ESSpanishes-US
Language.FRFrenchfr-FR
Language.DEGermande-DE
Language.ITItalianit-IT
Language.PTPortuguese (Brazil)pt-BR
Language.JAJapaneseja-JP
Language.KOKoreanko-KR
Language.ZHChinese (Mandarin)zh-CN

AWS Transcribe supports additional languages and regional variants. See the AWS Transcribe documentation for a complete list.

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Frame Flow

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Metrics Support

The service supports the following metrics:

  • Time to First Byte (TTFB)
  • Processing duration

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Notes

  • Requires valid AWS credentials with access to Amazon Transcribe
  • Supports real-time transcription with interim results
  • Handles WebSocket connection management and reconnection
  • Only supports mono audio (single channel)
  • Automatically handles audio format conversion to PCM
  • Manages connection lifecycle (start, stop, cancel)