As a reading system supporting video and audio playback I would like to have a way to provide script and synchronize with video/audio

[Jeffxz]

Introduction

I would like to define a way to let reading system synchronize script with audio/video if publisher could provide one.

This could be very useful for a11y or using video to learn languages. Sometimes temporarily I could not listen to video (noisy or some reasons) but I would still like to continue reading (script). Also for language learning books with audio/video it could be very helpful to synchronize with script.