Fluctuating KBps

[Jeff]

I have an mp3 file recently downloaded that when played with WinAmp, the numbers in the KBps display rapidly fluctuates, (112,128,160,192,224,256...) The song sounds perfect, but what could be causing the jumping numbers, (just curious). I didn't think an mp3 file could go beyond 160KBps which I think is oversampling?

Thanks http://forums.winamp.com/ubb/redface.gif) Jeff

[rew]

A variable bitrate encoded file.

[Olivier]

Yes, with more words:
The file you're playing is a VBR (Variable Bit Rate) encoded file. This means the used encoder is smart enough to use the needed bitrate in function of the spectral profile of the encoded packet of the stream/file.
By this way you "can" (theoritically) obtain similar-audio-quality smaller file than an CBR (Constant Bit Rate) file, if the encoder is "smart enough"...
But problem can appear, e.g. elapsed time can be false by fast forward or rewind a file, but it depends of the player you use...

Just to give you more info.