Flash streaming player: shoutcast (mp3 / aacplus), Windows media audio
http://www.adobe.com/devnet/flashplayer/articles/hd_video_flash_player.html explains Flash 9 h.264 and aac support. Presumably Flash can play aac audio without h.264 video. Someone wrote an ogg vorbis player in Flash ( http://drawlogic.com/2008/10/04/as3-fvorbis-flash-ogg-vorbis-player/ ) and the performance was acceptable. It is not written in ActionScript. It is written in another language that compiles to Flash compatible bytecode.
If you want to play wma, look no further than Silverlight. http://silverlight.net/forums/p/2786/7569.aspx lists all supported codecs. Silverlight 3 also allows you to create your own audio codecs in managed code.
JOrbis is a Java applet that can play ogg / vorbis including internet radio.
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SHOUTcast can be handled but not very well. Flash can trigger a scream-stream, but only as a simple MP3-over-HTTP request, so you don't get metadata. And since Flash fetches the stream as a whole file, the memory is filled with the loaded MP3. You can work around it by switching to a new stream every time so often, discarding old stream data, but this can leave a little desynchronization for each call again.
I've used minicaster for this before.
I don't know of anything that would play AAC or WMA. Flash 10 gives you direct access to audio output, allowing you to record / transfer an AAC or WMA decoder to ActionScript, but the performance will be terrible.
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Another way to play AAC shoutcast streams in a flash player would be to send the shoutcast stream to the wowza media server (this is easy to do from the wowza media server side, using a file as a folder content, for example shoutcast.stream, and launch it from the http panel : // [wowza address] / streammanager)
after that just play your scream thread using the wowza link you created:
rtmp://[wowza address]/live/flv:shoutcast.stream/playlist.m3u8
eg.
I noticed that you can use a full flash player if you can switch the stream link to .flv (seen this with Icecast v2 KH versions)
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