Use the Text to Speech API

Similarly to its Speech to text APIs, Azure Speech in Foundry Tools offers a Text to speech API for speech synthesis:

As with speech recognition, in practice most interactive speech-enabled applications are built using the Azure Speech SDK.

The pattern for implementing speech synthesis is similar to that of speech recognition:

1. Use a SpeechConfig object to encapsulate the information required to connect to your Azure Speech resource. Specifically, its location and key.
2. Optionally, use an AudioConfig to define the output device for the speech to be synthesized. By default, this is the default system speaker, but you can also specify an audio file, or by explicitly setting this value to a null value, you can process the audio stream object that is returned directly.
3. Use the SpeechConfig and AudioConfig to create a SpeechSynthesizer object. This object is a proxy client for the Text to speech API.
4. Use the methods of the SpeechSynthesizer object to call the underlying API functions. For example, the SpeakTextAsync() method uses the Azure Speech service to convert text to spoken audio.
5. Process the response from the Azure Speech service. In the case of the SpeakTextAsync method, the result is a SpeechSynthesisResult object that contains the following properties:
   • AudioData
   • Properties
   • Reason
   • ResultId

When speech has been successfully synthesized, the Reason property is set to the SynthesizingAudioCompleted enumeration and the AudioData property contains the audio stream (which, depending on the AudioConfig may have been automatically sent to a speaker or file).

Example - synthesizing text as speech

The following Python example uses Azure Speech in Foundry Tools to generate spoken output from text.

import azure.cognitiveservices.speech as speechsdk

# Speech config encapsulates the connection to the resource
speech_config = speechsdk.SpeechConfig(subscription=KEY, endpoint=ENDPOINT)

# Audio output config determines where to send the audio stream (defaults to speaker)
audio_config = speechsdk.audio.AudioOutputConfig(use_default_speaker=True)

# Use speech synthesizer to synthesize text as speech
speech_synthesizer = speechsdk.SpeechSynthesizer(speech_config=speech_config,
                                                 audio_config=audio_config)
text = "My voice is my password!"
speech_synthesis_result = speech_synthesizer.speak_text_async(text).get()

# Did it succeeed?
if speech_synthesis_result.reason == speechsdk.ResultReason.SynthesizingAudioCompleted:
    # Yes!
    print("Speech synthesized for text [{}]".format(text))
elif speech_synthesis_result.reason == speechsdk.ResultReason.Canceled:
    # No - Ty to find out why not
    cancellation_details = speech_synthesis_result.cancellation_details
    print("Speech synthesis canceled: {}".format(cancellation_details.reason))
    if cancellation_details.reason == speechsdk.CancellationReason.Error:
        if cancellation_details.error_details:
            print("Error details: {}".format(cancellation_details.error_details))