Windows 7: WMP 12: Good field for storing music origin info?

Is there an obvious field (Windows Media Player 12) in which to store the origin of music tracks that I have on my system? Until now I've been using Subgenre, but this is not such a good fit.

I've just come across "Content Provider" and this seems ideal. None of my 16,706 tracks have a value in this field, so I wouldn't be stepping on anyone's toes, probably.

Assuming there's no reason not to use this field, is there a practical way of moving the content of the Subgenre field into the Content Provider field? I've used OLE to read the WMP catalog, but so far I've never tried to update it this way. I'm a bit leery about experimenting on my music catalog...
Is the WMP catalog even the right thing to update? Maybe I should be looking at the IDV3 tags instead? I've never been sure of the relationship between the WMP Catalog and the IDV3 tags.



I can't use a mechanism which updates every track having a Subgenre, because changes to Subgenre are reflected in the IDV3 tags, which changes the file, so each changed track gets updated in my offsite backup, and my network can only cope with a few albums per day.

In case you're wondering why I'd want this information, it's so that I stand a chance of being able to prove that my music is legal, should the RIAA thought police think otherwise.

You can use lots of the tags in the MP3 for that kind of thing. I use 'grouping' for that purpose. Manipulating the tags in bulk is a bit more of an issue but there are several programs that can help. Media Monkey (has a free version) can assign tags to groups all at once. I use and really like Tag&Rename (shareware) for anything having to do with tags and managing my MP3 files--my lib is about the same size as yours. I don't know if either one can move a value from one tag to another automagically, never tried that. Bought T&R a long time ago and he keeps supporting it and issuing updates for as long as you want to get them--you could email him and see if it's something it will do. There are other packages out there that are probably as good but T&R works and at this point I'm completely familiar with it.

I use OLE to manipulate my tags in bulk. Starting with code like this:
Player=.OLEObject~New("WMPlayer.OCX.7")
If you're a programmer, and you code in a language that interfaces with OLE, you can have hours of endless fun playing with this stuff. Let me know if you'd like some help with this.

I ended up using the field "UserCustom1" (there is also a "UserCustom2") as it obviously won't collide with anything else on my system. For my purposes, it also has the advantage that it doesn't map to an ID3 tag. When I make system-wide changes that map into ID3 tags, it takes my backup system almost a week to ship out the changed files to my offsite backup mechanism (a Linux server in my friend's garage).

i cant help wondering why you think the RIAA will end up on your doorstep someday.
if you purchase online then there will be a record, if they are your cd rips then presumably you still have the cd's.
anyhow it is very very unlikely the copyright police would single you out