Renaming a filename without using tags

I have some MP3s that I would like to change the filenames of, without using tags, but then to retag them at the same time, so: a combined rename and retag operation, all in one.

Can mp3tag do this, or will I have to use batch file commands or another program entirely to rename first?

I simply lack the phantasy to imagine how one could rename and tag at the same time (it's probably sequential anyway) as a batchjob.
Could you give an example?
Or perhaps you have a look at the converter Filename-Filename and see what that can do for you.
And then there is the converter Filename-Tag - perhaps that also has some of the functions you need.
But without example I have to poke around in the mirky.

In the past I've done it outside of mp3tag with a bunch of MS-DOS "rename" commands in a batch file.

The thing is, I would like to specify a list of old > new filenames and send that to mp3tag (like the Text File > Tag function), and then to send a bunch of new tags using the actual Text File > Tag function.

Is this simply possible, using only mp3tag?

in a way: yes.
As the filename is used as identification you cannot rename it during the import. So you have to use a trick:
You could write a textfile that has all the data in it: the old filename, the new filename and the new tag data.
The trick is to write the new filename to a user-defined field, e.g. %new_filename%.
After the import the files still have the old name but the new tag data including the user-defined field NEW_FILENAME.
You then apply the Converter Tag-Filename with the mask
%new_filename%
Afterwards you can delete the user-defined field.

Thanks for the tip, ohrenkino!

I tried it just now, looks promising and of course it works, although I made use of the "comment" field instead of a user-defined one, as I'm not sure how to do that.

"Comment" is quite useful for me as I never normally use it, and it's an established MP3 tag already.

One thing, though: is there a way to clear a single type of tag from selected files? I find that the Remove Tag button (the red cross) nukes them all.

You create a user-defined field if you use a name that is not already a standard field. The list of standard fields can be found in the online help.
But: NEW_FILENAME is definitely a user-defined name.
So, for your text file you can define something like this:
%filename%;%new_filename%;%artist%;%title%

To get rid of fields again:

Select the files.
Press Alt-T to open the extended tags dialogue.
Select the entry for the field you want to delete and now press the red x button. Do this for all the fields you want to delete. Then click on OK to save the changes.

If you want to get rid of a certain field frequently, then you can create an action for this.

I'm using the %_filename_ext% tag for the original filename, and I find I have to provide the path (from the working directory) and the extension. However, it seems that only the filename, no path or extension, is needed for the %new_filename% tag - is that correct?

Yes.

Thanks for the information, it's been a great help to know such stuff.

But as for whether or not I'll put it into practice, I doubt it, as too many files have changed, and I've been using a simpler system that I think works out better, or at least more practical.

Thanks again!

If you want to streamline the process then I would think that the way of creating a new filename first could be subject to rationalization - the main concern for me there is that you do not recycle information.
If the filenames should have anything to do with the contents of the file then I guess that mp3tag would certainly have functions to generate new filenames out of file properties and tags. The program would then recycle the information and you are saved from typing it in all by yourself.
And even if you simply want to number them then there is also a function for that.
This would reduce the effort of thinking of new filenames, typing them in, starting the batchjob.