I'm not an audio guy. Can anyone explain like I'm five why this new codec was needed? How does it affect me as a consumer of audio? Who out there was saying "Gosh, I want to do X, but it's really tough because existing codecs force me to choose between high quality and low delay"? What is an example of "X" in that sentence?
Say you wanted to write a live audio chat app to talk to your friends. If you'd chosen the Speex codec, then voice would come over fine, but trying to show off your new guitar skills would fail because what they heard would sound horrible.
If you'd chosen the Vorbis codec, then everything would sound great, but there'd be a weird "lag" between participants, as if one of them were on the moon. Also, adding too many listeners would severely strain your internet connection's capacity.
Opus has latencies as good as Speex, and can be high-, medium-, or low-quality depending on bandwidth needs.
Look at the graph in the article. Opus is as good as or slightly better than all the existing codecs at their strong points, and much better than them at their weak points.
