wma (windows media audio) - nobody in the games scene seems to use this file format for pro games.
But why?

mp3 needs a license fee (with big projects)
ogg needs a driver/dll/...
wav is too big

but wma?

what's the problem with wma developing a windows based game - e.g. with GS? (licenses I do not know???)

Regardless of what you use, no-one is going to sue you unless your end product is worth something (except perhaps in North America, but might be mitigated if you take it on TV). Most Game Studio projects don't need to worry. Even if your game is massively successful it will probably work out at less than $1 per SKU.

I would avoid wma because it is owned by Microsoft and they might find a way to make it so your sound clips won't play on Windows if Micosoft don't want them to.

You can probably just use mp3. If you are sure you are going to sell ten or hundreds of thousands or you are worried about it, use ogg. Just remember to make your installation program intall it. Don't forget, like me).

The WMA APIs are a little annoying. It's easier to get a LAME or Ogg project set up. But once code is in place there's no reason not to use WMA. Keep in mind that there are different WMA versions, so you might have the user download updated codecs.

Now that is a statement based on facts and knowledge, brrr, . Why the heck should Microsoft turn off its own music format?

It`s all about what you want to do. Every format has its pros and cons.

For MP3 you have to pay $2700 when you reach 5000 copies of your game around. Which is quickly reached. More copies means of course more license fees. It is a Per Unit licensing. MP3 plays at nearly every Windows PC. MP3 comes with Media Player.

WMA Licensing is different from MP3. You pay the license with the software you own to create WMA. That's it. So own Wavelab or even just the Nero Wave recorder that can also save as WMA and you have paid your license. WMA plays at nearly every Windows PC. WMA comes with Media Player.

OGG has no licensing. It is free. Unfortunately the OGG codec doesn't come with Media Player. And so you have to provide the codec too when you use OGG for your music.

Honestly, WMA is my favourite format. No reason not to use it

But keep your hands away from MP3.

wma has also very good size<->quality ratio: demoloop 1.4MB/4min. (c by gameus) - looks like it's a good choice for GS games!

does ogg need an installed codec when using snd_play/loop()? i was under the impression that only streaming with media_play/loop() needs it?

Yes, that's right. But using snd_play in order to play a sound over multiple minutes might be a bad idea. Additionally the sounds will only be played in mono. So for background music you really should use media_play and install the .ogg codec if you don't want to use .wma or .mp3 files.