I’m surprised at how good MP3 can be. I’ve just tried a website that lets you do ABX tests between 128 and 320 kbps MP3 files. Presumably 320 kbps is meant to represent the “known transparent” sample (which should be true for my case). After getting one correct answer out of three, I stopped because it just wasn’t going to work out.
What’s surprising is not really the bitrate (I have previously ABX-tested Vorbis q2 (~96 kbps) and found it to be almost transparent); it’s that MP3 encoders have gone a long way since the last time I tried them. I guess most of their notoriety is carried over from the Napster era which, come to think of it, ended around ten years ago.
On a related note, MP3 and H.264 share an ironic trait: both are patent-encumbered, yet the best encoders for for them are free / open source software (LAME and x264). The difference is that MP3 is inferior to pretty much any of the other formats in use today.