UE4 Yandex Speech Kit

This is UE4 wrapper for Yandex Speech Kit speech recognition and synthesis cloud services.

Plugin was battle tested in several commercial simulator projects. The creators of the service are based in Russia, so russian language recognition and synthesis are there and it is main language with all features supported.

Preparation

1. Go to cloud console and create service account with editor or admin role. (1 month trial access available)

2. Create API key.

3. There are two ways how you can use your credentials.

   • 3.1 By using environment variables. Create environment variable YANDEX_API_KEY with created key as value.

   • 3.2 By assigning key directly in blueprints. This can be called anywhere.

   

   By default you need to set api key from nodes. To use environment variable, you need to set SetUseApiKeyFromEnvironmentVars to true.

ADVICE: Pay attention to security and encrypt your assets before packaging.

Speech synthesis

You need to supply text or ssml markup to async node, as well as audio quality, voice variant, speed and emotion. As output you will get sound wave object which can be played by engine.

Speech recognition

Consists of two parts. First, we need to record voice from microphone. To do that, use provided YandexMicrophoneCapture actor component as shown below. Next, construct recognition parameters and pass them to Yandex STT async node.

Probably you will need to send voice commands to you app, to increase recognition chances use CompareStrings node. Below call will return 0.454545 value, so we can treat those strings not equal, since they are similar on 45%.

Important steps

To make microphone work, you need to add following lines to Engine.ini of the project.

[Voice]
bEnabled=true

To not loose pauses in between words, you probably want to check silence detection treshold voice.SilenceDetectionThreshold, value 0.01 is good. This also goes to Engine.ini.

[SystemSettings]
voice.SilenceDetectionThreshold=0.01

Or by executing console command during runtime

Platforms supported

Windows

Links

Find out more in api documentation for corresponding sections.