Google Text-To-Speech With PHP (Simple Example)

Welcome to a tutorial on how to implement Google Cloud Text-to-Speech in PHP. So you are working on a PHP text-to-speech project, but only to find that Google’s documentation is kind of all over the place? Well, here is a simple working example of mine – Read on!

 

 

TABLE OF CONTENTS

 

 

EXAMPLE CODE DOWNLOAD

Source code on GitHub Gist

Just click on “download zip” or do a git clone. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

 

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PART 1) GOOGLE CLOUD ACCOUNT & TTS LIBRARY

Before we get into the code, there are quite a number of things you have to do.

 

1A) REGISTRATION

First, go through the “baptism by registration”:

• Register with Google Cloud if you have not already done so.
• Follow these instructions –
  • Create a project.
  • Enable text-to-speech API.
  • Create a service account.
  • Create a JSON key for your app.

 

 

1B) KEEP THE CREDENTIALS SAFE

Now, it’s easier to just download the credentials as a key.json file. But remember to keep it safe, there are 2 simple ways:

• If your public HTTP folder is at D:\http, just put the credentials outside. Maybe at D:\key.json.
• Put the credentials in a protected folder.
  • Create a lib folder.
  • Create a lib/.htaccess file – deny from all.
  • Move key.json inside lib/.
  • This is for Apache only. NGINX and IIS users – Do your own homework.

 

1C) GET THE TTS LIBRARY

• Install Composer if you have not already done so.
• Open the terminal, and navigate to your project folder – cd YOUR/PROJECT/.
• Run composer require google/cloud-text-to-speech.

Yep. That’s it for the “setup”.

 

 

PART 2) GET AVAILABLE VOICES

<?php
// (A) LOAD TTS LIBRARY
require "vendor/autoload.php";
use Google\ApiCore\ApiException;
use Google\Cloud\TextToSpeech\V1\ListVoicesResponse;
use Google\Cloud\TextToSpeech\V1\TextToSpeechClient;
$textToSpeechClient = new TextToSpeechClient(["credentials" => "key.json"]); // CHANGE TO YOUR OWN!
 
// (B) SAVE ENTIRE LIST TO FILE
try {
  $response = $textToSpeechClient->listVoices();
  file_put_contents("voices.json", $response->serializeToJsonString());
} catch (ApiException $ex) { print_r($ex); }
unset($response);
 
// (C) FILTER ENGLISH ONLY
$all = json_decode(file_get_contents("voices.json"), 1);
$en = [];
foreach ($all["voices"] as $v) { if (substr($v["name"], 0, 2) == "en") {
  $en[] = [
    "code" => $v["languageCodes"][0],
    "name" => $v["name"],
    "gender" => $v["ssmlGender"]
  ];
}}
 
// (D) SAVE FILTERED LIST
file_put_contents("voices-filtered.json", json_encode($en));
echo "OK";

Google offers a whole load of different voices and languages, we can use the library to get all of them – $textToSpeechClient->listVoices(). In this script, we generate:

• voices.json List of all the voices.
• voices-filtered.json English voices only.

Feel free to modify this to fit your own needs. Save the list into a database, or even generate HTML dropdown options directly.

 

 

PART 3) TEXT INPUT PAGE

<form method="post" target="_blank" action="3-process.php">
  <label>Voice</label>
  <select name="voice"><?php
    $all = json_decode(file_get_contents("voices-filtered.json"), 1);
    foreach ($all as $v) {
      printf("<option value='%s@%s'>%s (%s)</option>",
        $v["code"], $v["name"],
        $v["name"], $v["gender"]
      );
    }
  ?></select>
 
  <label>Text</label>
  <textarea name="txt" required></textarea>
 
  <label>Rate</label>
  <input type="range" min="0.5" max="4.0" value="1" step="0.5" name="rate" oninput="this.nextElementSibling.value = this.value">
  <output class="hint">1</output>

  <label>Pitch</label>
  <input type="range" min="-20" max="20" value="0" step="1" name="pitch" oninput="this.nextElementSibling.value = this.value">
  <output class="hint">0</output>
 
  <label>Gain</label>
  <input type="range" min="-15" max="15" value="5" step="1" name="gain" oninput="this.nextElementSibling.value = this.value">
  <output class="hint">5</output>

  <input type="submit" value="Go!">
</form>

Just a simple HTML form to select the voice, enter the text, rate, pitch, and gain.

 

 

PART 4) PROCESS TEXT-TO-SPEECH

<?php
// (A) LOAD TTS LIBRARY
require "vendor/autoload.php";
use Google\ApiCore\ApiException;
use Google\Cloud\TextToSpeech\V1\AudioConfig;
use Google\Cloud\TextToSpeech\V1\AudioEncoding;
use Google\Cloud\TextToSpeech\V1\SsmlVoiceGender;
use Google\Cloud\TextToSpeech\V1\SynthesisInput;
use Google\Cloud\TextToSpeech\V1\SynthesizeSpeechResponse;
use Google\Cloud\TextToSpeech\V1\TextToSpeechClient;
use Google\Cloud\TextToSpeech\V1\VoiceSelectionParams;
 
// (B) TEXT INPUT
$input = new SynthesisInput();
$input->setText($_POST["txt"]);
// $input->setSsml("<speak>" . $_POST["txt"] . "</speak>");
 
// (C) VOICE SETTING
$v = explode("@", $_POST["voice"]);
$voice = new VoiceSelectionParams();
$voice->setLanguageCode($v[0]);
$voice->setName($v[1]);
$audioConfig = new AudioConfig();
$audioConfig->setAudioEncoding(AudioEncoding::MP3);
$audioConfig->setSpeakingRate($_POST["rate"]); // 0.25 to 4.0
$audioConfig->setPitch($_POST["pitch"]); // -20 to 20
$audioConfig->setVolumeGainDb($_POST["gain"]); // -96 to 16
 
// (D) TEXT TO SPEECH
$textToSpeechClient = new TextToSpeechClient(["credentials" => "key.json"]); // CHANGE TO YOUR OWN!
$res = $textToSpeechClient->synthesizeSpeech($input, $voice, $audioConfig);
file_put_contents("demo.mp3", $res->getAudioContent());
echo "OK";

Lastly, we simply “forward” the submitted form to Google Cloud. Save the MP3 file to wherever you want.

 

 

 

SPEECH SYNTHESIS MARKUP LANGUAGE (SSML)

Just a quick sidenote that some voices in Cloud Text-To-Speech support SSML. For the uninitiated, you can call his “fine-tuning”. For example, adding emphasis:

<speak>
  This is <emphasis level="strong">SPARTA</emphasis>!
</speak>

There are a lot more, check out the link below if you want to learn more.

 

LINKS & REFERENCES

• Google Cloud Text To Speech PHP – GitHub
• SSML – Google Cloud