After encoding with cdex or exactaudiocopy, winamp shows always changing bitrates. Why?

The bitrate is changing because you have encoded a VBR (Variable Bitrate) MP3. If you wish to make Winamp display a static image of the average bitrate of the VBR file, go to Winamp preferences (ctrl+p), then to the Input plugins, and select Nullsoft MPEG Audio Decoder. Press the Configure button, go to the Decoder tab, and under Misc Options, check the "Show average bitrate on VBR files" box.

(below is some extra information you may or may not be aware of.)

VBR-encoded MP3's generally have better quality than CBR (Constant Bitrate) MP3's, but for guaranteed best MP3 quality you should use the alt-presets to encode your MP3's; they have been rigorously tested to give the best possible sound. If you have any questions, or have no idea what I'm talking about, don't hesitate to ask! Welcome to the forum.

Hi,
First of all, CDex and EAC are rippers, not encoders. They just read the binary data off the cd.

About the bitrate, it depends on what codec and settings you choose. If you encode using LAME in variable bitrate, it's normal that the bitrate changes all the time.

streaming (~64kbps) goal: constant bitrate, acceptable quality
audiophile goal: guaranteed quality, variable bitrate (depending on the complexity of the music).

For example, if there's a 10-second silence in the middle of your song, what would be the point to encode those 10 seconds in 256kbps ?

Thanx for answer. Yeah the programs are rippers, but the use lame for encoding. Thanx also for explanation of VBR. I thought up to now, that this changing bitrates (in downloades mp3's) are faults of the encoder.

Another question. I watched the link (alt-presets), and i think i understand the settings, but where can i change the settings in my encoder. i.e. when i use CDex, is this the "quality" setting (low, standard, very high quality...) in the encoder configuration?

First open CDex, if the title bar doesn't say 'CDex Version 1.50 Beta 10' then you need to download the newest version from:
http://cdexos.sourceforge.net/download.php

In CDex 1.50 Beta 10 this is how you enable the --alt-preset switches using the LAME DLL 'lame_enc.dll':
1. Click F4, or click the gear in the toolbar.
2. Click the Encoder tab.
3. For encoder click LAME MP3 Encoder (version 1.30, engine 3.92 MMX)
4. For quality select --alt-preset standard
You don't have to touch any other setting, now you will get the recommended encoding quality.