I have some PowerPoint files that contain audio narration on every slide. I am viewing these slides using LibreOffice Impress. Is there a way to increase the playback speed of these narrations? I would like to adjust the speed to 1.25x, 1.5x or even 2x.
No, I am not aware that LibreOffice can do this.
You might try the tool “Audacity”. But then you have to set up your individual audio clips again.