Get automatic punctuation

This page describes how to get automatic punctuation in transcription results from Speech-to-Text. When you enable this feature, Speech-to-Text automatically infers the presence of periods, commas, and question marks in your audio data and adds them to the transcript.

By default, Speech-to-Text does not include punctuation marks in the results from speech recognition. However, you can request that Speech-to-Text automatically detect and insert punctuation in transcription results. When you enable automatic punctuation Speech-to-Text will also automatically capitalize the first letter after each period and question mark.

To enable automatic punctuation, set the enableAutomaticPunctuation field to true in the RecognitionConfig parameters for the request. The Speech-to-Text API supports automatic punctuation for all speech recognition methods: speech:recognize, speech:longrunningrecognize, and Streaming.

The following code samples demonstrate how to get automatic punctuation details in a transcription request.

Protocol

Refer to the speech:recognize API endpoint for complete details.

To perform synchronous speech recognition, make a POST request and provide the appropriate request body. The following shows an example of a POST request using curl. The example uses the Google Cloud CLI to generate an access token. For instructions on installing the gcloud CLI, see the quickstart. 

curl -s -H "Content-Type: application/json" \
    -H "Authorization: Bearer "$(gcloud auth print-access-token) \
    https://speech.googleapis.com/v1/speech:recognize \
    --data '{
  "config": {
    "encoding":"FLAC",
    "sampleRateHertz": 16000,
    "languageCode": "en-US",
    "enableAutomaticPunctuation": true
  },
  "audio": {
    "uri":"gs://cloud-samples-tests/speech/brooklyn.flac"
  }
}'

See the RecognitionConfig reference documentation for more information on configuring the request body.

If the request is successful, the server returns a 200 OK HTTP status code and the response in JSON format:

{
  "results": [
    {
      "alternatives": [
        {
          "transcript": "How old is the Brooklyn Bridge?",
          "confidence": 0.98360395
        }
      ]
    }
  ]
}

Go

To learn how to install and use the client library for Speech-to-Text, see Speech-to-Text client libraries. For more information, see the Speech-to-Text Go API reference documentation.

To authenticate to Speech-to-Text, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 


func autoPunctuation(w io.Writer, path string) error {
	ctx := context.Background()

	client, err := speech.NewClient(ctx)
	if err != nil {
		return fmt.Errorf("NewClient: %w", err)
	}
	defer client.Close()

	// path = "../testdata/commercial_mono.wav"
	data, err := ioutil.ReadFile(path)
	if err != nil {
		return fmt.Errorf("ReadFile: %w", err)
	}

	resp, err := client.Recognize(ctx, &speechpb.RecognizeRequest{
		Config: &speechpb.RecognitionConfig{
			Encoding:        speechpb.RecognitionConfig_LINEAR16,
			SampleRateHertz: 8000,
			LanguageCode:    "en-US",
			// Enable automatic punctuation.
			EnableAutomaticPunctuation: true,
		},
		Audio: &speechpb.RecognitionAudio{
			AudioSource: &speechpb.RecognitionAudio_Content{Content: data},
		},
	})
	if err != nil {
		return fmt.Errorf("Recognize: %w", err)
	}

	for i, result := range resp.Results {
		fmt.Fprintf(w, "%s\n", strings.Repeat("-", 20))
		fmt.Fprintf(w, "Result %d\n", i+1)
		for j, alternative := range result.Alternatives {
			fmt.Fprintf(w, "Alternative %d: %s\n", j+1, alternative.Transcript)
		}
	}
	return nil
}

Java

To learn how to install and use the client library for Speech-to-Text, see Speech-to-Text client libraries. For more information, see the Speech-to-Text Java API reference documentation.

To authenticate to Speech-to-Text, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

/**
 * Performs transcription on remote FLAC file and prints the transcription.
 *
 * @param gcsUri the path to the remote FLAC audio file to transcribe.
 */
public static void transcribeGcsWithAutomaticPunctuation(String gcsUri) throws Exception {
  try (SpeechClient speechClient = SpeechClient.create()) {
    // Configure request with raw PCM audio
    RecognitionConfig config =
        RecognitionConfig.newBuilder()
            .setEncoding(AudioEncoding.FLAC)
            .setLanguageCode("en-US")
            .setSampleRateHertz(16000)
            .setEnableAutomaticPunctuation(true)
            .build();

    // Set the remote path for the audio file
    RecognitionAudio audio = RecognitionAudio.newBuilder().setUri(gcsUri).build();

    // Use non-blocking call for getting file transcription
    OperationFuture<LongRunningRecognizeResponse, LongRunningRecognizeMetadata> response =
        speechClient.longRunningRecognizeAsync(config, audio);

    while (!response.isDone()) {
      System.out.println("Waiting for response...");
      Thread.sleep(10000);
    }

    // Just print the first result here.
    SpeechRecognitionResult result = response.get().getResultsList().get(0);

    // There can be several alternative transcripts for a given chunk of speech. Just use the
    // first (most likely) one here.
    SpeechRecognitionAlternative alternative = result.getAlternativesList().get(0);

    // Print out the result
    System.out.printf("Transcript : %s\n", alternative.getTranscript());
  }
}

Node.js

To learn how to install and use the client library for Speech-to-Text, see Speech-to-Text client libraries. For more information, see the Speech-to-Text Node.js API reference documentation.

To authenticate to Speech-to-Text, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

// Imports the Google Cloud client library for API
/**
 * TODO(developer): Update client library import to use new
 * version of API when desired features become available
 */

const speech = require('@google-cloud/speech');
const fs = require('fs');

// Creates a client
const client = new speech.SpeechClient();

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 * Include the sampleRateHertz field in the config object.
 */
// const filename = 'Local path to audio file, e.g. /path/to/audio.raw';
// const encoding = 'Encoding of the audio file, e.g. LINEAR16';
// const sampleRateHertz = 16000;
// const languageCode = 'BCP-47 language code, e.g. en-US';

const config = {
  encoding: encoding,
  languageCode: languageCode,
  enableAutomaticPunctuation: true,
};

const audio = {
  content: fs.readFileSync(filename).toString('base64'),
};

const request = {
  config: config,
  audio: audio,
};

// Detects speech in the audio file
const [response] = await client.recognize(request);
const transcription = response.results
  .map(result => result.alternatives[0].transcript)
  .join('\n');
console.log('Transcription: ', transcription);

Python

To learn how to install and use the client library for Speech-to-Text, see Speech-to-Text client libraries. For more information, see the Speech-to-Text Python API reference documentation.

To authenticate to Speech-to-Text, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import argparse

from google.cloud import speech


def transcribe_file_with_auto_punctuation(path: str) -> speech.RecognizeResponse:
    """Transcribe the given audio file with auto punctuation enabled."""
    client = speech.SpeechClient()

    # path = 'resources/commercial_mono.wav'
    with open(path, "rb") as audio_file:
        content = audio_file.read()

    audio = speech.RecognitionAudio(content=content)
    config = speech.RecognitionConfig(
        encoding=speech.RecognitionConfig.AudioEncoding.LINEAR16,
        sample_rate_hertz=8000,
        language_code="en-US",
        # Enable automatic punctuation
        enable_automatic_punctuation=True,
    )

    response = client.recognize(config=config, audio=audio)

    for i, result in enumerate(response.results):
        alternative = result.alternatives[0]
        print("-" * 20)
        print(f"First alternative of result {i}")
        print(f"Transcript: {alternative.transcript}")

    return response

Additional languages

C#: Please follow the C# setup instructions on the client libraries page and then visit the Speech-to-Text reference documentation for .NET.

PHP: Please follow the PHP setup instructions on the client libraries page and then visit the Speech-to-Text reference documentation for PHP.

Ruby: Please follow the Ruby setup instructions on the client libraries page and then visit the Speech-to-Text reference documentation for Ruby.

What's next

Review how to make synchronous transcription requests.