Opus is an advanced audio codec, first released in September 2012. It's now almost 4 years old and I'm astonished, that so few people know about it.
In a nutshell
Opus is much better than mp3 and you should switch to it as fast as possible.
- OPUS offers better sound quality than mp3
- OPUS makes the same audio files smaller than mp3
- You can already use it on most of your devices
There is no reason at all you should still use mp3 and not move to Opus (or OGG Vorbis). Both are generally better in terms of audio quality and compression rate.
Opus - Some details
Opus is offering a significantly better audio quality compared to mp3 and even OGG Vorbis1.
In reality, there is no reason to still stuck with the old mp3 audio format. It was the thing of our generation to have music in a quite reliable, small data format on different devices, but it has become old and obsolete. There is no reason at all to stick to mp3, even OGG Vorbis is significantly better in compression rate, audio quality and it's a free codec, whereas mp3 is a non-free codec witch means, that every Software and device is charged some license fees in order you can use it.
According to 1 and 3 the audio quality of OPUS is much better than mp3 and compares even to HE-AAC.
Can I already use it?
Opus is build-in in most modern Browsers. It has build-in support in Firefox and Chrome, and also Edge is about to include it2 (another reason why Edge is broken). VLC supports opus and on Android you should find at least one player, that suits you and can play Opus.
In Linux it is available as a package and ships with most of the latest distros.
How to convert files from mp3 to Opus
For Windows users:
I've not found a suitable tool for the conversion of OPUS, but you can use freac to convert your files to Ogg Vorbis
opusenc input.wav output.opus
To convert an mp3 on-the fly use the following snipped, and modify the bitrate to your needs
avconv -i input.mp3 -f wav - | opusenc --bitrate 256 - output.opus
(Found on askubuntu.com)