audio player is not accessible with screen readers
I am blind, so use a screen reader to access the web. However, your audio player (not sure about video) is inaccessible with them. For example, the play button shows to my screen reader as a clickable of 'black up pointing small triangle" which is not very descriptive. However, when I do click on the triangle, the pause button is a symbol that my screen reader cannot recognize, which simply speaks as clickable. This is on windows, using jaws for windows. I haven't tested with NVDA (an open source screen reader), but with orca on linux, the clickable isn't even seen at all, and there is no way to play the audio.
For audio (and video, possibly) I can recommend able player (https://ableplayer.github.io/ableplayer/) as an alternative that is guaranteed to be accessible if done right. IT could also introduce new features, such as closed captions and transcripts on videos.