ALTextToSpeech Tutorial

Overview | API | Tutorial

This tutorial explains how to say a sentence, change the voice effects, or change the language and the voice of the synthesis engine.

Note

All the examples provided are written in Python.

Creating a proxy on the module

Before using the TTS commands, you need to create a proxy on the TTS module.

# Creates a proxy on the text-to-speech module
from naoqi import ALProxy

IP = "<IP ADDRESS>"
tts = ALProxy("ALTextToSpeech", IP, 9559)

Saying a text string

You can say a sentence using the say function.

# Example: Sends a string to the text-to-speech module
tts.say("Hello World!")

Modifying pitch

The API allows some modifications of the voice’s pitch. Example:

tts.setParameter("pitchShift", 1.1)

This command raises the pitch of the main voice. 1.1 is the ratio between the fundamental frequency of the transformed voice and the original one.

Modifying double voice parameters

The double voice rendering can be modified using 3 parameters:

  • doubleVoice: the ratio between the fundamental frequency of the transformed voice and the original one.
  • doubleVoiceLevel: the ratio between the volume of the second voice and the first one.
  • doubleVoiceTimeShift: the time shift between the second voice and the first one.

For example, a “robotic sounding” voice can be generated using these commands:

tts.setParameter("doubleVoice", 1)
tts.setParameter("doubleVoiceLevel", 0.5)
tts.setParameter("doubleVoiceTimeShift", 0.1)
tts.setParameter("pitchShift", 1.1)

Changing the language of the synthesis engine

The language of the synthesis engine can be changed using the setLanguage function. The list of the available languages can be obtained with the getAvailableLanguages function.

# Example: set the language of the synthesis engine to English:
tts.setLanguage("English")

Changing the voice of the synthesis engine

You can also change the voice of the synthesis engine with the setVoice function. The list of the available voices can be obtained with the getAvailableVoices function. When you change the voice, the current language is automatically changed by the language corresponding to this voice.

# Example: use the voice of Kenny:
tts.setVoice("Kenny22Enhanced")

Saving and loading voice preferences

The voice preferences are the set of synthesis and FX parameters that allows to customize voices. If you want to keep a set of synthesis and FX parameters, you can save it in a ”.xml” preference file in the “/home/nao/naoqi/preferences” folder and load it with the loadVoicePreference method.

The preference file must be formatted as described below:

<ModulePreference schemaLocation="ModulePreference.xsd" name="aldebaran-robotics.com@ALTextToSpeech_Voice_defaultEnglish">
  <Preference value="Kenny22Enhanced" type="string" name="sourceVoice" description="Synthesis source voice"/>
  <Preference value="0.0" type="float" name="doubleVoice" description="Ratio of pitch shifting applied to the doubling voice"/>
  <Preference value="0.0" type="float" name="doubleVoiceLevel" description="Level of the doubling voice"/>
  <Preference value="0.0" type="float" name="pitchShift" description="Ratio of the pitch shifting applied to the main voice"/>
  <Preference value="0.125" type="float" name="doubleVoiceTimeShift" description="Delay (ms) between the double voice and the main voice"/>
</ModulePreference>

The name of the ”.xml” file must begin by ALTextToSpeech_Voice_ and finish by the name of the voice you want to load with the loadVoicePreference method.

For example, the following piece of code loads the set of voices parameters contained in the “ALTextToSpeech_Voice_NaoOfficialVoiceEnglish.xml” file of the preference folder.

tts.loadVoicePreference("NaoOfficialVoiceEnglish")
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