Transcribing a real-time stream using a medical custom vocabulary - Amazon Transcribe

Transcribing a real-time stream using a medical custom vocabulary

To improve transcription accuracy in a real-time stream, you can use a custom vocabulary using either HTTP/2 or WebSocket streams. To start an HTTP/2 request, use the StartMedicalStreamTranscription API. You can use a custom vocabulary in real-time using either the AWS Management Console, the StartMedicalStreamTranscription API, or by using the WebSocket protocol.

To use the AWS Management Console to transcribe streaming audio of a medical dictation, choose the option to transcribe a medical dictation, start the stream, and begin speaking into the microphone.

To transcribe streaming audio of a medical dictation (AWS Management Console)

  1. Sign in to the AWS Management Console.

  2. In the navigation pane, under Amazon Transcribe Medical, choose Real-time transcription.

  3. For Medical specialty, choose the medical specialty of the clinician speaking in the stream.

  4. For Audio input type, choose either Conversation or Dictation.

  5. For Additional settings, choose Custom vocabulary.

    1. For Vocabulary selection, choose the custom vocabulary.

  6. Choose Start streaming.

  7. Speak into the microphone.

The following is the syntax for the parameters of an HTTP/2 request.

POST /medical-stream-transcription HTTP/2
host: transcribestreaming.us-west-2.amazonaws.com
authorization: Generated value
x-amz-target: com.amazonaws.transcribe.Transcribe.StartMedicalStreamTranscription
x-amz-content-sha256: STREAMING-MED-AWS4-HMAC-SHA256-EVENTS
x-amz-date: 20220208T235959Z
x-amzn-transcribe-session-id: my-first-http2-med-stream
x-amzn-transcribe-language-code: en-US
x-amzn-transcribe-media-encoding: flac
x-amzn-transcribe-sample-rate: 16000
x-amzn-transcribe-vocabulary-name: my-first-med-vocab
x-amzn-transcribe-specialty: PRIMARYCARE
x-amzn-transcribe-type: CONVERSATION
x-amzn-transcribe-show-speaker-label: true
Content-type: application/vnd.amazon.eventstream
transfer-encoding: chunked

Parameter descriptions:

  • host: Update the AWS Region ('us-west-2' in the preceding example) with the AWS Region you are calling. For a list of valid AWS Regions, see AWS Regions and Endpoints.

  • authorization: This is a generated field. To learn more about creating a signature, see Signing AWS requests with Signature Version 4.

  • x-amz-target: Don't alter this field; use the content shown in the preceding example.

  • x-amz-content-sha256: This is a generated field. To learn more about calculating a signature, see Signing AWS requests with Signature Version 4.

  • x-amz-date: The date and time the signature is created. The format is YYYYMMDDTHHMMSSZ, where YYYY=year, MM=month, DD=day, HH=hour, MM=minute, SS=seconds, and 'T' and 'Z' are fixed characters. For more information, refer to Handling Dates in Signature Version 4.

  • x-amzn-transcribe-session-id: The name for your streaming session.

  • x-amzn-transcribe-language-code: The encoding used for your input audio. Refer to StartMedicalStreamTranscription or Supported languages and language-specific features for a list of valid values.

  • x-amzn-transcribe-media-encoding: The encoding used for your input audio. Valid values are pcm, ogg-opus, and flac.

  • x-amzn-transcribe-sample-rate: The sample rate of the input audio (in Hertz). Amazon Transcribe supports a range from 8,000 Hz to 48,000 Hz. Low-quality audio, such as telephone audio, is typically around 8,000 Hz. High-quality audio typically ranges from 16,000 Hz to 48,000 Hz. Note that the sample rate you specify must match that of your audio.

  • x-amzn-transcribe-vocabulary-name: The name of the vocabulary you want to use with your transcription.

  • x-amzn-transcribe-specialty: The medical specialty being transcribed.

  • x-amzn-transcribe-type: Choose whether this is a dictation or a conversation.

  • x-amzn-transcribe-show-speaker-label: To enable diarization, this value must be true.

  • content-type: Don't alter this field; use the content shown in the preceding example.

To partition speakers in WebSocket streams with the API, use the following format to create a pre-signed URI to start a WebSocket request and set vocabulary-name to the name of the custom vocabulary. 

GET wss://transcribestreaming.us-west-2.amazonaws.com:8443/medical-stream-transcription-websocket
?language-code=en-US
&X-Amz-Algorithm=AWS4-HMAC-SHA256
&X-Amz-Credential=AKIAIOSFODNN7EXAMPLE%2F20220208%2Fus-west-2%2Ftranscribe%2Faws4_request
&X-Amz-Date=20220208T235959Z
&X-Amz-Expires=300
&X-Amz-Security-Token=security-token
&X-Amz-Signature=Signature Version 4 signature 
&X-Amz-SignedHeaders=host
&media-encoding=flac
&sample-rate=16000
&session-id=sessionId
&specialty=medicalSpecialty
&type=CONVERSATION
&vocabulary-name=vocabularyName
&show-speaker-label=boolean