I received some constructive feedback on my post arguing that internet radio should retire MP3 streaming.
Twitter user Mark Mollineaux pointed out that browser-compatibility is a consideration:
@RadioSurvivor MP3 has by far the best cross-browser compatibility. I'd prefer an open standard like ogg, but many browser's won't play it–
— Mark Mollineaux (@bufordsharkley) May 11, 2015
This is important because having in-browser support for your stream’s codec means that the listener doesn’t have to download or install any kind of player app or plug-in. Even though plug-ins like Flash often seem ubiquitous, there are schools and work-places that prohibit adding any plug-ins. So, if your station’s stream requires one, then you won’t reach listeners in these places.
HTML5Test.com lets you compare browser feature sets, so I assembled a comparison of all major web browsers (Chrome, Firefox, Internet Explorer, Opera and Safari) for their audio codec support. It turns out that both MP3 and AAC are supported by the most recent versions of all of them. Only users of much older versions, like Internet Explorer 8 (the current version is 11) are out of luck. This means that a station can safely switch over its primary stream to AAC stream with very little risk.
Nathan Moore, General Manager at WTJU-FM, let me know that his station uses the open source and royalty-free Ogg Opus codec as its streaming default. Opus can be seen as a more modern descendent of the Ogg Vorbis codec which was developed to provide an alternative to MP3 that wasn’t restricted by royalty fees.
I tuned in to WTJU’s 256kbps streams and found that they sound very good. The principal knock against Opus is that it is much less widely supported than AAC or MP3. Amongst major desktop browsers Chrome, Firefox and Opera will all play Opus streams, but the default browsers for Windows and MacOS, Internet Explorer and Safari, will not. Neither Android nor iOS support Opus natively, either. That said, Opus is the newest audio codec–version 1.0 was released in 2012.
The point still remains that there are very good alternatives to MP3 that provide superior quality at lower bitrates, and which are widely supported enough that MP3 can be made secondary, or even abandoned altogether.