Speaking addresses with SSML

This tutorial demonstrates how to use Speech Synthesis Markup Language (SSML) to speak a text file of addresses. You can mark up a string of text with SSML tags to personalize synthetic audio from Text-to-Speech.

Plaintext SSML rendering of plaintext
123 Street Ln
<speak>123 Street Ln</speak>
1 Number St
<speak>1 Number St</speak>
1 Piazza del Fibonacci
<speak>1 Piazza del Fibonacci</speak>

Objective

Send a synthetic speech request to Text-to-Speech using SSML and Text-to-Speech client libraries.

Costs

Refer to the Text-to-Speech pricing page for cost information.

Before you begin

Downloading the code samples

To download the code samples, clone the Google Cloud GitHub samples for the programming language that you intend to use.

Java

This tutorial uses code in the texttospeech/cloud-client/src/main/java/com/example/texttospeech/ directory of the Google Cloud Platform Java samples.

To download and navigate to the code for this tutorial, run the following commands from the terminal.

git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git
cd java-docs-samples/texttospeech/cloud-client/src/main/java/com/example/texttospeech/

Node.js

This tutorial uses code in the nodejs-text-to-speech/samples directory of the googleapis repository.

To download and navigate to the code for this tutorial, run the following commands from the terminal.

git clone https://github.com/googleapis/nodejs-text-to-speech.git
cd nodejs-text-to-speech/samples/

Python

This tutorial uses code in the texttospeech/cloud-client directory of the Google Cloud Platform Python samples.

To download and navigate to the code for this tutorial, run the following commands from the terminal.

git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git
cd python-docs-samples/texttospeech/cloud-client/

Installing the client library

This tutorial uses the Text-to-Speech client library.

Java

This tutorial uses the following dependencies.

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-texttospeech</artifactId>
  <version>0.117.0-beta</version>
</dependency>

Node.js

From terminal, run the follow command.

npm install @google-cloud/text-to-speech

Python

From terminal, run the follow command.

pip install --upgrade google-cloud-texttospeech

Setting up your Google Cloud Platform credentials

Provide authentication credentials to your application code by setting the environment variable GOOGLE_APPLICATION_CREDENTIALS. Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename. This variable only applies to your current shell session, so if you open a new session, set the variable again.

Linux or macOS

export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

For example:

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/[FILE_NAME].json"

Windows

With PowerShell:

$env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

For example:

$env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

With command prompt:

set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

Importing libraries

This tutorial uses the following system and client libraries.

Java

// Imports the Google Cloud client library
import com.google.cloud.texttospeech.v1.AudioConfig;
import com.google.cloud.texttospeech.v1.AudioEncoding;
import com.google.cloud.texttospeech.v1.SsmlVoiceGender;
import com.google.cloud.texttospeech.v1.SynthesisInput;
import com.google.cloud.texttospeech.v1.SynthesizeSpeechResponse;
import com.google.cloud.texttospeech.v1.TextToSpeechClient;
import com.google.cloud.texttospeech.v1.VoiceSelectionParams;
import com.google.common.html.HtmlEscapers;
import com.google.protobuf.ByteString;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Paths;

Node.js

// Imports the Google Cloud client library
const textToSpeech = require('@google-cloud/text-to-speech');

// Import other required libraries
const fs = require('fs');
//const escape = require('escape-html');
const util = require('util');

Python

from google.cloud import texttospeech

import html

Using Text-to-Speech API

The following function takes a string of text tagged with SSML and the name of an MP3 file. The function uses the text tagged with SSML to generate synthetic audio. The function saves the synthetic audio to the MP3 filename designated as a parameter.

Java

/**
 * Generates synthetic audio from a String of SSML text.
 *
 * <p>Given a string of SSML text and an output file name, this function calls the Text-to-Speech
 * API. The API returns a synthetic audio version of the text, formatted according to the SSML
 * commands. This function saves the synthetic audio to the designated output file.
 *
 * @param ssmlText String of tagged SSML text
 * @param outFile String name of file under which to save audio output
 * @throws Exception on errors while closing the client
 */
public static void ssmlToAudio(String ssmlText, String outFile) throws Exception {
  // Instantiates a client
  try (TextToSpeechClient textToSpeechClient = TextToSpeechClient.create()) {
    // Set the ssml text input to synthesize
    SynthesisInput input = SynthesisInput.newBuilder().setSsml(ssmlText).build();

    // Build the voice request, select the language code ("en-US") and
    // the ssml voice gender ("male")
    VoiceSelectionParams voice =
        VoiceSelectionParams.newBuilder()
            .setLanguageCode("en-US")
            .setSsmlGender(SsmlVoiceGender.MALE)
            .build();

    // Select the audio file type
    AudioConfig audioConfig =
        AudioConfig.newBuilder().setAudioEncoding(AudioEncoding.MP3).build();

    // Perform the text-to-speech request on the text input with the selected voice parameters and
    // audio file type
    SynthesizeSpeechResponse response =
        textToSpeechClient.synthesizeSpeech(input, voice, audioConfig);

    // Get the audio contents from the response
    ByteString audioContents = response.getAudioContent();

    // Write the response to the output file
    try (OutputStream out = new FileOutputStream(outFile)) {
      out.write(audioContents.toByteArray());
      System.out.println("Audio content written to file " + outFile);
    }
  }
}

Node.js

/**
 * Generates synthetic audio from a String of SSML text.
 *
 * Given a string of SSML text and an output file name, this function
 * calls the Text-to-Speech API. The API returns a synthetic audio
 * version of the text, formatted according to the SSML commands. This
 * function saves the synthetic audio to the designated output file.
 *
 * ARGS
 * ssmlText: String of tagged SSML text
 * outfile: String name of file under which to save audio output
 * RETURNS
 * nothing
 *
 */
async function ssmlToAudio(ssmlText, outFile) {
  // Creates a client
  const client = new textToSpeech.TextToSpeechClient();

  // Constructs the request
  const request = {
    // Select the text to synthesize
    input: {ssml: ssmlText},
    // Select the language and SSML Voice Gender (optional)
    voice: {languageCode: 'en-US', ssmlGender: 'MALE'},
    // Select the type of audio encoding
    audioConfig: {audioEncoding: 'MP3'},
  };

  // Performs the Text-to-Speech request
  const [response] = await client.synthesizeSpeech(request);
  // Write the binary audio content to a local file
  const writeFile = util.promisify(fs.writeFile);
  await writeFile(outFile, response.audioContent, 'binary');
  console.log('Audio content written to file ' + outFile);
}

Python

def ssml_to_audio(ssml_text, outfile):
    # Generates SSML text from plaintext.
    #
    # Given a string of SSML text and an output file name, this function
    # calls the Text-to-Speech API. The API returns a synthetic audio
    # version of the text, formatted according to the SSML commands. This
    # function saves the synthetic audio to the designated output file.
    #
    # Args:
    # ssml_text: string of SSML text
    # outfile: string name of file under which to save audio output
    #
    # Returns:
    # nothing

    # Instantiates a client
    client = texttospeech.TextToSpeechClient()

    # Sets the text input to be synthesized
    synthesis_input = texttospeech.types.SynthesisInput(ssml=ssml_text)

    # Builds the voice request, selects the language code ("en-US") and
    # the SSML voice gender ("MALE")
    voice = texttospeech.types.VoiceSelectionParams(
        language_code='en-US',
        ssml_gender=texttospeech.enums.SsmlVoiceGender.MALE)

    # Selects the type of audio file to return
    audio_config = texttospeech.types.AudioConfig(
        audio_encoding=texttospeech.enums.AudioEncoding.MP3)

    # Performs the text-to-speech request on the text input with the selected
    # voice parameters and audio file type
    response = client.synthesize_speech(synthesis_input, voice, audio_config)

    # Writes the synthetic audio to the output file.
    with open(outfile, 'wb') as out:
        out.write(response.audio_content)
        print('Audio content written to file ' + outfile)

Personalizing synthetic audio

The following function takes in the name of a text file and converts the contents of the file into a string of text tagged with SSML.

Java

/**
 * Generates SSML text from plaintext.
 *
 * <p>Given an input filename, this function converts the contents of the input text file into a
 * String of tagged SSML text. This function formats the SSML String so that, when synthesized,
 * the synthetic audio will pause for two seconds between each line of the text file. This
 * function also handles special text characters which might interfere with SSML commands.
 *
 * @param inputFile String name of plaintext file
 * @return a String of SSML text based on plaintext input.
 * @throws IOException on files that don't exist
 */
public static String textToSsml(String inputFile) throws Exception {

  // Read lines of input file
  String rawLines = new String(Files.readAllBytes(Paths.get(inputFile)));

  // Replace special characters with HTML Ampersand Character Codes
  // These codes prevent the API from confusing text with SSML tags
  // For example, '<' --> '&lt;' and '&' --> '&amp;'
  String escapedLines = HtmlEscapers.htmlEscaper().escape(rawLines);

  // Convert plaintext to SSML
  // Tag SSML so that there is a 2 second pause between each address
  String expandedNewline = escapedLines.replaceAll("\\n", "\n<break time='2s'/>");
  String ssml = "<speak>" + expandedNewline + "</speak>";

  // Return the concatenated String of SSML
  return ssml;
}

Node.js

/**
 * Generates SSML text from plaintext.
 *
 * Given an input filename, this function converts the contents of the input text file
 * into a String of tagged SSML text. This function formats the SSML String so that,
 * when synthesized, the synthetic audio will pause for two seconds between each line
 * of the text file. This function also handles special text characters which might
 * interfere with SSML commands.
 *
 * ARGS
 * inputfile: String name of plaintext file
 * RETURNS
 * a String of SSML text based on plaintext input
 *
 */
function textToSsml(inputFile) {
  let rawLines = '';
  // Read input file
  try {
    rawLines = fs.readFileSync(inputFile, 'utf8');
  } catch (e) {
    console.log('Error:', e.stack);
    return;
  }

  // Replace special characters with HTML Ampersand Character Codes
  // These codes prevent the API from confusing text with SSML tags
  // For example, '<' --> '&lt;' and '&' --> '&amp;'
  let escapedLines = rawLines;
  escapedLines = escapedLines.replace(/&/g, '&amp;');
  escapedLines = escapedLines.replace(/"/g, '&quot;');
  escapedLines = escapedLines.replace(/</g, '&lt;');
  escapedLines = escapedLines.replace(/>/g, '&gt;');

  // Convert plaintext to SSML
  // Tag SSML so that there is a 2 second pause between each address
  const expandedNewline = escapedLines.replace(/\n/g, '\n<break time="2s"/>');
  const ssml = '<speak>' + expandedNewline + '</speak>';

  // Return the concatenated String of SSML
  return ssml;
}

Python

def text_to_ssml(inputfile):
    # Generates SSML text from plaintext.
    # Given an input filename, this function converts the contents of the text
    # file into a string of formatted SSML text. This function formats the SSML
    # string so that, when synthesized, the synthetic audio will pause for two
    # seconds between each line of the text file. This function also handles
    # special text characters which might interfere with SSML commands.
    #
    # Args:
    # inputfile: string name of plaintext file
    #
    # Returns:
    # A string of SSML text based on plaintext input

    # Parses lines of input file
    with open(inputfile, 'r') as f:
        raw_lines = f.read()

    # Replace special characters with HTML Ampersand Character Codes
    # These Codes prevent the API from confusing text with
    # SSML commands
    # For example, '<' --> '&lt;' and '&' --> '&amp;'

    escaped_lines = html.escape(raw_lines)

    # Convert plaintext to SSML
    # Wait two seconds between each address
    ssml = '<speak>{}</speak>'.format(
        escaped_lines.replace('\n', '\n<break time="2s"/>'))

    # Return the concatenated string of ssml script
    return ssml

Putting it all together

This program uses the following input.

123 Street Ln, Small Town, IL 12345 USA
1 Jenny St & Number St, Tutone City, CA 86753
1 Piazza del Fibonacci, 12358 Pisa, Italy

Passing the above text to text_to_ssml() generates the following tagged text.

<speak>123 Street Ln, Small Town, IL 12345 USA
<break time="2s"/>1 Jenny St &amp; Number St, Tutone City, CA 86753
<break time="2s"/>1 Piazza del Fibonacci, 12358 Pisa, Italy
<break time="2s"/></speak>

Running the code

To generate an audio file of synthetic speech, run the following code from the command line.

Java

Linux or MacOS

From the java-docs-samples/texttospeech/cloud-client/ directory, execute the following command on the command line.

$ mvn clean package

Windows

From the java-docs-samples/texttospeech/cloud-client/ directory, execute the following command on the command line.

$ mvn clean package

Node.js

Linux or MacOS

In the hybridGlossaries.js file, uncomment the TODO (developer) commented-out variables.

In the following command, replace projectId with your Google Cloud project ID. From the nodejs-text-to-speech/samples directory, execute the following command on the command line.

$ node ssmlAddresses.js projectId

Windows

In the hybridGlossaries.js file, uncomment the TODO (developer) commented-out variables.

In the following command, replace projectId with your Google Cloud project ID. From the nodejs-text-to-speech/samples directory, execute the following command on the command line.

$env: C:/Node.js/node.exe C: ssmlAddresses.js projectId

Python

Linux or MacOS

From the python-docs-samples/texttospeech/cloud-client/ directory, execute the following command on the command line.

$ python ssml_addresses.py

Windows

From the python-docs-samples/texttospeech/cloud-client/ directory, execute the following command on the command line.

$env: C:/Python3/python.exe C: ssml_addresses.py

Checking your output

This program outputs an example.mp3 audio file of synthetic speech.

Java

Navigate into java-docs-samples/texttospeech/cloud-client/resources/ directory.

Check the resources directory for an example.mp3 file.

Node.js

Navigate into nodejs-text-tospeech/samples/resources/ directory.

Check the resources directory for an example.mp3 file.

Python

Navigate into python-docs-samples/texttospeech/cloud-client/resources.

Check the resources directory for an example.mp3 file.

Listen to the following audio clip to check that your example.mp3 file sounds the same.


Troubleshooting

  • Forgetting to set the GOOGLE_APPLICATION_CREDENTIALS environment variable on the command line generates the error message:

    The Application Default Credentials are not available.

  • Passing text_to_ssml() the name of a non-existent file generates the error message:

    IOError: [Errno 2] No such file or directory
    

  • Passing ssml_to_audio() a ssml_text parameter which contains None generates the error message:

    InvalidArgument: 400 Invalid input type. Type has to be text or SSML
    

  • Make sure that you are running the code from the correct directory.

What's next

Cleaning up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this tutorial, use the Google Cloud Console to delete your project if you do not need it.

Deleting your project

  1. In the Cloud Console, go to the Projects page.
  2. In the project list, select the project you want to delete and click Delete.
  3. In the dialog box, type the project ID, and click Shut down to delete the project.
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