I just discovered an annoying effect of adding ID3 V2 tags and wonder if anyone can shed some light on the problem. I just recently ripped and encoded to mp3 several cds using EAC and the latest version of Lame. I have Lame set to use the alt-preset extreme setting and checked the boxes in EAC compression options under the ID3 tab to a) write ID3 V2 tags using a padding of 4 kB and b) use ID3 V2.4 instead of V2.3.
Anyway the VBR Mp3s turned out great but only an ID3 V1 tag was written. OK, no big deal, I just went into Winamp and copied from the V1 tag to create a V2, clicked update and carried on. The problem is that when I was doing some checking of file info later I discovered that the bitrates were no longer variable, they were rounded down. For instance what was originally a 235 kbit VBR, 44100Hz joint stereo mp3 was now a 160kbit, 48000Hz stereo file. Also, while the file initially said 'Yes" to original and CRCs, it now said no. Even more interesting is that when I delete the ID3 V2 tag and update, everything returns to normal.
What gives? How can writing an extra tag change the fundamental file structure? Or is Winamp just falsely reporting this info due to some kind of glitch? Any thoughts, or better yet, any solid explanations? I want the extra info and longer titles that V2 tags afford, but not at the expense of sound quality. ???

There is something called Xing header that is put first in VBR mp3 files. It contains information about how long the file is (in time domain), and this info is needed to calculate average bitrate. When you add an ID3v2 tag to the file this is also placed in the beginning of the file, and it seems like your player now doesn't find the Xing header anymore.

Edit: but when I try what you did, I can't reproduce the bug.

Edit2: I missed the part about id3v2.4 .... Use id3v2.3 instead.

Thanks for your response, but I'm still not clear on what is happening. Is the creation of the ID3 v2 tag actually able to convert a VBR file to CBR, or is it being falsely reported? Also, since EAC failed to write the V2 tags in the first place (I have no idea why), I'm forced to create the V2 tag by copying from V1 and there's no indication in Winamp as to whether the tag is V2.3 or 2.4

I think the problem here is that Winamp doesn't recognize ID3v2.4, but it is on your files. When you add another ID3v2 tag before the original one, Winamp doesn't know how to read correct file info anymore. Try removing the 2.4 tag first and re-create 2.3.

That makes sense, but how would I go about removing the v2.4 tag. I assume it was created during the initial rip. Does this mean I have to go back and rip and encode everything from scratch with the EAC option for v2.4 unchecked?

Well, I think there are programs to convert 2.4 to 2.3, I just don't know any. I think Tag can remove 2.4, but I'm not sure as I have never tried it.

No, you don't have to. The tag can be removed and I'm sure some program exists that can convert it.

Thanks for the help. I'll see if Google turns something up for removing the v2.4 tag.

I tested Tag, it can delete v2.4. You can give it a try if you don't find anything else.