Duration disappears on some songs

Hi, I'm new to the forums (signed up about a minute ago)
I've been searching for so long and I can't seem to find a topic that is somewhat similar to mine. So here goes:

I'm not really familiar with the program. I've used it for just two days. And the way I used it is this:

I launch it, I click on "change directory" choose the music folder I want to edit, I wait for it to load and then I edit everything manually.

I usually just delete the comments and track number sections because I prefer them empty.
So say I load "music folder A" with 20 songs (song1 - song20), Once they're all listed on the main window, I then proceed to manually remove all the comments and track numbers. After that, I press ctrl+A to select all the files and then click on the save button.

I then open up windows explorer to check if my changes were saved. The comments section doesn't really show but the track number does, so I usually base it there.

The problem is, once I save it, the duration disappears on some songs.

That being said, I'd like to clarify a few things:

  1. They all had durations prior to saving my "tags"
  2. I did NOT touch the duration column, I don't even go near it.
  3. I saw somewhere here that if files don't play, I should check the validity of the file. Someone suggested mp3val. I've downloaded it and evaluated all my files prior to "tagging" All were scanned and turned out OK.
  4. This does not happen to all the files. Just to one or two every folder. Say for "music folder A" with song1 - song20, after removing the comments and track numbers and saving, one song will somehow end up without a duration, rendering it unplayable.

Am I doing something wrong?
If so, please help me.. So far 6 mp3 files have already lost their durations, cannot be played and I must download again.

Lastly, I apologize if this was posted before. I'm very unfamiliar with the forums and I only searched the site through Google. I'm sorry if this has been discussed.

Any help will be greatly appreciated.

Did you check whether these files had an "extended tag" "length" to them? In MP3tag:
select your tracks,
press Alt-T
check the list of displayed tags:
if you see a "length" tag, then something is wrong as you cannot edit length tags. They are determined during compilation.

if you cannot be sure that your manipulations may lead to corrupt files then create backups before editing.

If you have found a track that "looses" its length then check if you can play the backup file. If so, try to recode it.

Also, there is foobar2000 that has built-in utilities to fix the mp3-stream and some tags. Maybe that is helpful.

To sum it all up: tagging with MP3tag does not corrupt your files unless they were corrupted already. MP3tag only delivers the message.

Thank you for your reply.

I did as you said with the current music folder I'm working on. This folder has 23 files. I selected them all then pressed alt+T like you said and the "length" did show up. So what I did was press alt+T on them one by one to determine which of my files were dysfunctional and ended up with three files.

Now that I've filtered them out as the ones having "length", I'm sort of stuck. You said there's something wrong, what exactly is wrong with it and how do I fix it?

Also, is there any way I can filter those that have length tags? I'm working on thousands of music files, it'll take me forever pressing alt+T on each of them to check for length tags.

Again, thanks for your initial reply. I didn't know there was this much technicalities with songs. Honestly it's making my head spin. But your help definitely made it easier.

Try running some of the problem files through MP3 Diags and see if any errors show up.

The program will also repair most of the problems it finds.

Thank you, I'll do that and come back with results. Thanks again.. =)

Coming back to the "length" tag:
This tag is just an indicator that something may be wrong. E.g. CDex always sets the header to VBR and adds a length field even if you have encoded files as CBR only. These files then may not allow random seek. Or upset the tagging.

Usually it is safe to delete the superfluous tags as they are useless.

So, use one of the suggested repair programs.
If the repair is not successful try to re-encode the corrupt files from your backup.
Then everything should be AOK and you should be able to continue tagging.

Oh yes: I think you can filter for the extra length field (the one that indicates trouble)

NOT %length% IS ""