You can also highlight and annotate in an epub reader/manager, like Calibre or MarginNote, then export those to Obsidian.
Not a direct integration per se but worth letting apps that already handle media deal with it rather than turning Obsidian into a kitchen sink. What’s next? Native mp3 and mp4? Just saying it would benefit us all if the core devs continue to focus on the core value prop.
</end mini-rant>