Interesting post from Jon Udell that could have some application for Hypothesis users. Jon (who is the Director of Integration for Hypotheis) has been tinkering with methods to make annotating audio on the web possible. His post is technical, but it gives a glimpse into how he is thinking about the challenge of linking to and annotating multimedia on the web.
While this is still early days, Jon's experiments show that annotating audio is something that can be done using the built in HTML5 media players that come standard with most current browsers. Here is an example from NPR that Jon has annotated.
To be clear, this is not something that Hypothesis supports right now (afaik). This is more like Jon working on the open taking a first crack at it (indeed, the annotation I tested from NPR worked in Firefox and Chrome, but not MS Edge, which illustrates the early experimental nature of his work). But it does appear that annotating audio and video is on their roadmap.
Considering how much more multimedia is on the web today, it isn't hard to see how linking and annotating could both be incredibly useful tools for educators.
Source: Annotating web audio, Jon Udell, January, 2018