Mp3tag and files created by mp3wrap

I have been testing a free utility called mp3wrap ( which is (according to it's publicity) "a command-line utility that wraps quickly two or more mp3 files in one single large playable mp3, without losing filenames and ID3 information". The point is to create a single large file, which can be easily split back into its component files if desired. The claim is that the wrapped file is a valid mp3 file. I have tried it, and it certainly works, but Mp3Tag is unable to correctly identify the length of the wrapped file. For example, the combined length of 24 files on my system is shown by Mp3Tag to be 1hour 11 minutes. I then wrap them, and Mp3Tag shows the length of the wrapped file to be 43 minutes. I have played the wrapped file, and it is definitely 1hr 11 minutes.

Is anyone here familiar with Mp3Wrap, and can you tell me why Mp3Tag does not identify the correct length of the wrapped file?

As I am very new to these sorts of things, are there any problems with wrapped files which would prevent knowledgeable people from using them?

(The main purpose I have for using them is for posting audiobook CDs to a newsgroup where some people want the CDs in their original form - all the small tracks - but the news group policy is to keep the number of posted files and headers to a minimum. The group also does not allow zip or rar files to be posted. Hence, my idea is to post the files in a wrapped form. People who like big files can play the wrapped file as a single mp3, and other people can split the file back to its component files).

I use Mp3Tag version 2.43, Windows XP Pro SP3.

Though there is commercial container format in the market field of audiobooks, I have never heard of mp3wrap/mp3split tools. It seems to be a clever but oldish project from 2003, not supported anymore.

You can check a copy of your mp3 wrapped file with the foobar 2000 application.
Use the track right click "Utils" menu functions "Fix VBR MP3 Header" and "Rebuild MP3 Stream" and see what happens with your mp3 wrapped file.