Your transcript feature will be the best feature if It will be like lynda.com player.
1) Boundaries (with adjustable size) for subtitle text. Main idea is to keep player near to text subtitles for keeping eye on video and subtitles below video player in the same time.
2) Current subtitle auto-focus within subtitles boundaries, after rewind in player time bar. Also a “Resume Auto-Scroll” button.
3) Subtitles as links with background highlighting when mouse hover and when subtitle is current.
In some all lynda.com transcript features.