[just_for_you]

This pretty much nails it.

I also do appreciate MP3's simplicity, in the sense that it's just a series of concatenated frames. It makes it really easy to just fling them over the network and get streaming audio working on a client. And there's also somewhat of an elegance (a very ugly and hacky elegance, mind you) to being able to exploit decoders ignoring malformed frames.

For example if you open an MP3 IceCast stream via HTTP in a media player like VLC, the server (if it realizes, via the HTTP request headers, that you're Icecast-aware) will occasionally barf the name of the current and following song into the MP3 stream. Meaning you don't need any higher-level streaming protocol to deal with, and can just send raw frames over the wire, where the MP3 decoder will ignore the song title as a malformed MP3 frame, but VLC will pick-up on the song title and display it for you as the server cycles from one song to the next. Kinda handy, because VLC will make use of this metadata, but at the same time, the MP3 stream's URL will also work in a web browser too, since the browser won't need to know how to deal with a higher-level protocol before being able to start receiving those frames.

Actually, nevermind all that. MP3 bad.

[dfox]

IIRC IceCast essentially extends/abuses HTTP/1.1 chunked encoding to frame such metadata. The original Nullsoft's ShoutCast protocol simply multiplexes fixed size blocks of mp3 data with length prefixed metadata packets. In both cases you can pretty easily strip the metadata out.

[grishka]

Back when di.fm was an actual online radio and gave you a stream URL to play in a player of your choice, it was dead simple. I don't know what protocol it used, but there was no chunked encoding and no content-length, simply a 200 OK HTTP response and then an endless MP3 "file" with ID3 tags inserted every now and then. You could play it with Android's MediaPlayer in like 3 lines of code.

Oh and by the way. For this exact purpose, ID3v2 has a flag called "unsynchronized" that means all 0xFF bytes in that field are replaced with 0xFF00, so that players won't play the wrong thing. You're supposed to replace them back when parsing the tag. A very hacky solution.