PowerPoint Keyboard Shortcuts to Play and Control Video During ... - Adobe
To seek forward 0.25 seconds, then pause, press Alt + Shift + right arrow To seek backward 0.25 seconds, then pause, press Alt + Shift + left arrow Control the volume of a video during a slide show To increase the volume, press Alt + up arrow. To decrease the volume, press Alt + down arrow. To mute the sound, press Alt + U.