if the files that make up your multiple artist albums are placed in their individual album directories, have the same album tag, but different artist tags, MC will automatically assign them an "[album artist (auto)]" tag of (Multiple Artists) and we can then leverage this when creating renaming rules. If they are not in the same directory, for any reason, then the "[album artist (auto)]" field will be the same as the artist field. To force the issue here, you would need to set the [album artist] field of those albums to (Multiple Artists). It's a really neat system that Doof explained quite well in this post:
http://yabb.jriver.com/interact/index.php?board=3;topic=33255.1#msg227823So, assuming your multiple artist albums all reflect the desired [album artist (auto)] value of (Multiple Artists) :
Select file or files, right click, choose, library tools > rename files from properties. In the dialogue that shows, choose a "base directory", then, in the directories field, paste the following:
if(isequal([album artist (auto)],multiple artists,8),[album artist (auto)]\[album],if(isequal([album],unknown,8),mid([artist])\[artist]\,mid([artist])\[artist]\[album]))
and in the filename field, paste the following:
if(isequal([album artist (auto)],/(multiple,8),[track #] - [artist] - [name],[track #] - [name])
Would give the following, assuming a base path of D:\
D:\(Multiple Artists)\Greatest Hits of the Eighties\01 - Mike Oldfield - Moonlight Shadow.mp3
D:\P\Pink Floyd\Wish you were here\03 - Have a Cigar.mp3
D:\P\Pink Floyd\10 - some track without an album tag.mp3
The logic being applied is that if the artist name is in the folder path, it is not required in the filename, unless it's a (Multiple Artist) album, in which case, it might be kind of useful to have the artist in the filename. Try it on two or three files, and if you're happy, try it on a few more. If your basic tagging is OK, you should be able to select all audio and run those rules over them with confidence.
Note:
Do
Not be playing any tracks when doing this job.
If the change in structure involves moving the files from one drive to another, pay attention to the messages in the status bar at the bottom of MC, they will tell you when the task is complete.
If the change in structure does not require a change of drive name, the process will be done in a matter of seconds.
See how you get on, and don't worry too much if things go awry, as there's a high probability that any mistakes or oversights can be just as easily rectified.
The above information makes several assumptions regarding the present state of multi artist albums and disc # tags. The info is there for you to make of what you will. It may be that it will do for you exactly as it is, or perhaps it will need a little tweaking here or there.
If you give precise information about the current state of your tags, and how you ultimately want things arranged on your hard drive, you'll get a more precise answer. You with me here? If you do use the strings above, and things don't work quite as expected, don't get stressed, just say what happened, and what you'd rather had happened and we'll take it from there, or state exactly what you want, in order to find out exactly what you need to get there.
-marko.