I'm a layman and I need someone to explain to me the basics of media players capable of embedding hd video in a website. I am building an education website that will require instructional videos. I need a video player that will allow users to adjust the playback speed of the video (possibly using a slide-bar or pre-determined speed options), and add various layers of audio to a given video (i.e. watch without sound, watch with one layer of audio, watch with audio and narration overlaid).
I don't necessarily need a developer to build this for me now, but I would be willing to pay someone to explain to me what the options for existing video players, their potential for extensibility and customization, etc.