I've found at least one sample here I'd like to edit for use in a game I'm writing to be distributed under the terms of the GPL. There's more than one CC licence and I'm not sure which one freesound uses. Is it compatible with the GPL provided my game's documentation includes the appropriate credits?
This is fine if you attribute the sample authors somewhere. If your game has credits, please credit the sample authors there. At the very minimum, you should put an AUTHORS text file in the sample directory, and/or have attribution on the website where the game can be downloaded from.
Specifically for the GPL, the "mere aggregation" clause of the GPLv2 allows for you to distribute stuff with the game that is not GPL licensed. So yeah, all things equal, it should be compatible.
Sorry for the delayed response.
I have a very similar question. My planned game has no special license. (I think the license doesn't matter here as it is not an advert game, right?) It will be proprietary (non-opensource). Maybe a stupid question: How to attribute authors, simply write their nickname used here into readme file or credits? Do I have to attribute this site as well? If I would not have to, should I? And what about sounds packed/crypted in the data files to be non-accessible for a normal user? Is it possible (even for changed/derived sounds)?
Thank you in advance.
If the sound can be heard by people playing the game, you must credit it in a way that is visible to them. Readme file works, but if you have credits programmed into the actual game you should definitely attribute there if possible.
Please see the attribution FAQ: