So, I've downloaded tons of MP3s from TESNexus to augment the vanilla Oblivion music. I dumped them all into the appropriate folder, expecting that Oblivion would magically start using them...but while Oblivion will play some of the new ones, probably around 80% of them are being ignored in-game. (For example, of the 80 Combat tracks I have, I hear the same 15 over and over again.)


Are there rules around which MP3s Oblivion will and won't use? Do they have to be a certain bitrate, named a certain way, etc.? Is there a limit to how many can be in a given folder?

No access to them at the moment, but I seem to recall that all the vanilla MP3s were encoded at a constant bitrate of 192kb/s.

Other than that, if indeed that is an issue (or a factor), perhaps some tracks are made using an incompatible encoder...? You could try re-encoding them, though I believe that would result in a loss of quality, unfortunately. And besides, I have not heard of such an issue before...

Or do the tracks have non-ANSI characters in their filenames/titles? It is possible Oblivion would have issues with that, though I do not know for certain.

The only time I added a lot of MP3s to Oblivion, I used the Better Music System mod, which seemed to handle everything quite well.

I think many of the tracks were 128kbps, in fact. But the difference in quality ingame is scarcely detectable; and generally music volume has to be toned down anyway to hear everything else that's going on. Even larger or variable bit-rates take up more space and can actually contribute to game stutter, so IMO there's little benefit in using them. I generally re-encode everything I put in my game music directory to constant 128 using Fraunhofer, and save the 320's and flac's for Foobar .
And yes, I have seen a few instances where Oblivion steadfastly refused to play a particular mp3 even if it was the only track in the folder--re-encoding was the only solution--but that's uncommon.

What's more likely going on is that the Oblivion engine doesn't like to work real hard with regard to randomizing music. It won't search the hard drive for other tracks if it can find one quickly, and then it will often choose a shorter track rather than pause to load a long one. Defragging your hard drive after adding a lot of music will help some. But far and away the best solution is Better Music System, as arafel said ... if you're lucky enough to be able to use it. Not real sure why, and I'm not willing to test it because mine still works ... but whether it's the operating system, sound card driver or something else, the dll that BMS depends on just doesn't work on some systems. There has been a call for someone to update it so that it works reliably again, but as of yet that hasn't happened.

Also keep in mind, Oblivion doesn't like the Meta Tags in MP3 files. It tends to skip those files which include such information entirely.
The more information (interpreter, album, category, you-name-it) there is in the MP3 the less likely it is Oblivion will use it. Though last time I read of it it was only the tags specifically. But with Oblivion you can never be too sure about anything.

Aha! They are 192 kb/s. Not that that is likely to be the issue.

The constant bitrate aspect to it all... might be.

Sounds like it's time for some reencoding magic then - switch everything to 192 kbps CBR and no tags, and see what happens. Thanks for the advice!

I've noticed that as well, though usually Oblivion seems to pick some tracks over others and play the crap out of them. I wish there were a system that would apply tags to a track and not play it until after a certain amount of time or a certain number of other tracks have played. Maybe BMS does this already? I tried it a long time ago, but I couldn't get it to work.