Speech-to-Text API: Qwik Start

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Speech-to-Text API: Qwik Start

Lab 30 minutes universal_currency_alt 1 Credit show_chart Introductory
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The Speech-to-Text API enables easy integration of Google speech recognition technologies into developer applications. The Speech-to-Text API allows you to send audio and receive a text transcription from the service.

What you'll learn

In this lab, you learn how to:

  • Create an API key
  • Create a Speech-to-Text API request
  • Call the Speech-to-Text API

Setup and requirements

Before you click the Start Lab button

Read these instructions. Labs are timed and you cannot pause them. The timer, which starts when you click Start Lab, shows how long Google Cloud resources will be made available to you.

This hands-on lab lets you do the lab activities yourself in a real cloud environment, not in a simulation or demo environment. It does so by giving you new, temporary credentials that you use to sign in and access Google Cloud for the duration of the lab.

To complete this lab, you need:

  • Access to a standard internet browser (Chrome browser recommended).
Note: Use an Incognito or private browser window to run this lab. This prevents any conflicts between your personal account and the Student account, which may cause extra charges incurred to your personal account.
  • Time to complete the lab---remember, once you start, you cannot pause a lab.
Note: If you already have your own personal Google Cloud account or project, do not use it for this lab to avoid extra charges to your account.

How to start your lab and sign in to the Google Cloud console

  1. Click the Start Lab button. If you need to pay for the lab, a pop-up opens for you to select your payment method. On the left is the Lab Details panel with the following:

    • The Open Google Cloud console button
    • Time remaining
    • The temporary credentials that you must use for this lab
    • Other information, if needed, to step through this lab
  2. Click Open Google Cloud console (or right-click and select Open Link in Incognito Window if you are running the Chrome browser).

    The lab spins up resources, and then opens another tab that shows the Sign in page.

    Tip: Arrange the tabs in separate windows, side-by-side.

    Note: If you see the Choose an account dialog, click Use Another Account.
  3. If necessary, copy the Username below and paste it into the Sign in dialog.

    {{{user_0.username | "Username"}}}

    You can also find the Username in the Lab Details panel.

  4. Click Next.

  5. Copy the Password below and paste it into the Welcome dialog.

    {{{user_0.password | "Password"}}}

    You can also find the Password in the Lab Details panel.

  6. Click Next.

    Important: You must use the credentials the lab provides you. Do not use your Google Cloud account credentials. Note: Using your own Google Cloud account for this lab may incur extra charges.
  7. Click through the subsequent pages:

    • Accept the terms and conditions.
    • Do not add recovery options or two-factor authentication (because this is a temporary account).
    • Do not sign up for free trials.

After a few moments, the Google Cloud console opens in this tab.

Note: To view a menu with a list of Google Cloud products and services, click the Navigation menu at the top-left. Navigation menu icon

Task 1. Create an API key

Since you'll be using curl to send a request to the Speech-to-Text API, you need to generate an API key to pass in our request URL.

  1. To create an API key, click Navigation menu > APIs & services > Credentials.

  2. Then click Create credentials.

  3. In the drop down menu, select API key.

  4. Copy the key you just generated and click Close.

Click Check my progress to verify the objective.

Create an API Key

Now that you have an API key, save it as an environment variable to avoid having to insert the value of your API key in each request.

To perform the next steps, connect using SSH to the instance provisioned for you.

  1. In the Navigation menu, select Compute Engine. You should see a linux-instance listed in the VM instances window.

  2. Click on the SSH button in line with the linux-instance. You will be brought to an interactive shell.

  3. In the command line, enter in the following, replacing <YOUR_API_KEY> with the API key you copied from previously generated:


You remain in this SSH session for the rest of the lab.

Task 2. Create your Speech-to-Text API request

Note: You will use a pre-recorded file that's available on Cloud Storage: gs://cloud-samples-tests/speech/brooklyn.flac. Listen to the audio file before sending it to the Speech-to-Text API.
  1. Create request.json in the SSH command line. You'll use this to build your request to the Speech-to-Text API:
touch request.json
  1. Open the request.json:
nano request.json Note: You can use your preferred command line editor (nano, vim, emacs) or gcloud. This lab will provide instructions for nano.
  1. Add the following to your request.json file, using the uri value of the sample raw audio file:
{ "config": { "encoding":"FLAC", "languageCode": "en-US" }, "audio": { "uri":"gs://cloud-samples-tests/speech/brooklyn.flac" } }
  1. Press control + x and then y to save and click Enter to close the request.json file.

The request body has a config and audio object.

In config, you tell the Speech-to-Text API how to process the request. The encoding parameter tells the API which type of audio encoding you're using while the file is being sent to the API. FLAC is the encoding type for .raw files. Learn more about encoding types in the RecognitionConfig Guide.

There are other parameters you can add to your config object, but encoding is the only required one.

In the audio object, you pass the API the uri of the audio file in Cloud Storage.

Click Check my progress to verify the objective.

Create your Speech-to-Text API request

Now you're ready to call the Speech-to-Text API!

Task 3. Call the Speech-to-Text API

  1. Pass your request body, along with the API key environment variable, to the Speech-to-Text API with the following curl command (all in one single command line):
curl -s -X POST -H "Content-Type: application/json" --data-binary @request.json \ "${API_KEY}"

Your response should look something like this:

{ "results": [ { "alternatives": [ { "transcript": "how old is the Brooklyn Bridge", "confidence": 0.98267895 } ] } ] }

The transcript value will return the Speech-to-Text API's text transcription of your audio file, and the confidence value indicates how sure the API is that it has accurately transcribed your audio.

You'll notice that you called the syncrecognize method in the request above. The Speech-to-Text API supports both synchronous and asynchronous speech to text transcription. In this example you sent it a complete audio file, but you can also use the syncrecognize method to perform streaming speech to text transcription while the user is still speaking.

You created a Speech-to-Text API request then called the Speech-to-Text API.

  1. Run the following command to save the response in a result.json file:
curl -s -X POST -H "Content-Type: application/json" --data-binary @request.json \ "${API_KEY}" > result.json

Click Check my progress to verify the objective.

Call the Speech-to-Text API


You used the Speech-to-Text API to retrieve a transcript of an input audio file.

Next steps / Learn more

This lab is also part of a series of labs called Qwik Starts. These labs are designed to give you a little taste of the many features available with Google Cloud. Search for "Qwik Starts" in the lab catalog to find the next lab you'd like to take!

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Manual Last Updated February 13, 2024

Lab Last Tested October 13, 2023

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