decoding mp3 in a commercial product

[cool mr croc]

I can use any number of free libraries to decode mp3, currently I'm using core audio on mac and libav on windows, but where do they stand on the mp3 license you need to purchase for commercial products? As core audio is part of mac, does that mean the license has been paid for? are there any libraries I can use for windows that come with a license already?

I had been putting a lot of effort into ridding myself the need of FMOD, but now FMOD seems a very cheap alternative to paying the mp3 license myself.

[heepoo]

you can use lame to work with MP3 files
but you need to use it as a dll because it is a GPL licensed library

[cool mr croc]

I wouldnt be able to distribute the lame dll, would i need to alert the user to install it, then create code to search for it?

[helios]

I don't think you can get around paying royalties by simply not distributing the decoder with your main program. Patents cover using the technology, not simply distributing it.
Patents are issued on a country-by-country basis, so if you live somewhere where MP3 is not patented (e.g. a country without software patents) you don't have to pay any royalties.

http://mp3licensing.com/patents/index.html

Mandatory IANAL.

[cool mr croc]

well im in england, i heard all the patents had expired here and that theyre only still applicable in US. if that were true could i do what i want and distribute to who i want or would i ned to not distribute to us?

[helios]

AFAIK, yes, but you'd be well advised to check with a lawyer who specializes in patent law.

[cool mr croc]

audacity seem to get away with it by using the LAME codec as a 3rd party user installed library. it downloads from a server in Argentina.

[helios]

Well, Audacity is not a commercial application. Also there are subtleties depending on how code interfaces with other code.
For instance, if I have an application that exposes a generic plugin interface for decoding arbitrary formats and someone makes a plugin that decodes MP3, then surely I can't be held accountable for that. The one infringing the patent (or not) is the developer of that plugin. I wouldn't be surprised to find out that that library was developed by someone who lives here specifically because we don't have software patents, and that it interfaces with Audacity in the manner I just described.