That's a really insightful way of putting it. My first reaction was, 'well, duh...', but then I realized that I'd taken for granted the fact that digital video

That's a really insightful way of putting it. My first reaction was, 'well, duh...', but then I realized that I'd taken for granted the fact that digital video of (arbitrarily defined) adequate quality must have a much higher information rate than audio of the same. But surely there are animals for which the opposite is true!