Performance impact while using narrator above 1.16 update, SAPI5 handling.

Summary:

While narrator is set to “narrates all” the game will freeze every time when navigating in the GUI or using inventory (e. g. opening chests). This can be reproduced by using high quality SAPI5 voices such as Ivona. Because game communicates with SAPI synchronously, the game will wait for response from TTS engine effectively freezing the game. Bug don’t occurs on linux or MacOS.

Steps to reproduce:

1. set narrator to “narrates all” or “narrates system” (narrates chat is excluded)

2. just navigate around any game screens, while going from one to another you should feel lag

3. in some cases while exiting the game can crash

Guides to achieve bug:

• use high quality TTS engine for SAPI5 (32 or 64 bit)

• use old TTS engines such as eSpeak for windows

Expected Behaviour:

Text-to-speech synthesis should be fully asynchronous and should not block the main render or server ticks, regardless of the underlying SAPI5 voice engine complexity.