Source required for art licensed under the GPL

Source required for art licensed under the GPL

It appears that there is a lot of content on which is listed as licensed under the GPL, but no source files are available.

First, the GPL is quite specific that the license applies to all copyrightable works, not just source code for computer programs. Second, the distributor of a work that is licensed under the GPL has to make the source of that work available, otherwise you are violating the license. Last, even if you think the GPL doesn't apply, and if the work is not dual-licensed under another license, then default copyright applies, which means that the work is not distributable.

The "source" of a work is defined in the GPL to be the preferred form of modification of a work. If you take a picture or record some samples, then that can reasonably called the source. However, especially for music, just the OGG or MP3 file is not the preferred form of modification. In case of music, the music score and any information required to turn it into an OGG or MP3 file is a reasonable source. That means a MOD file is fine, because it contains the source as well as the samples required to generate the final sound output. A MIDI file with setup files for a software synthesizer would also be fine.

A lot of works on OGA are dual-licensed, and I think the uploaders just intend their work to be useable by as many projects as possible. While that is very good, the GPL still requires the distributor to provide the sources. It would be best if works that don't have reasonable source files available just have their GPL license removed. If they are only available under a GPL license, then I believe the work should be removed from OGA, and the uploader informed so they can decide whether or not to provide the sources and/or allow the work to be used under a more appropriate license, like CC-BY-SA.

Since there is so much which is incorrectly licensed, it would be helpful if OGA would automatically forbid the GPL license on past and future uploads in the music category that only contain .ogg, .mp3 or .wav formats. For music it is rather clear-cut, for sound effects and images it might be harder to tell whether something is source or not. It might also help if the submission form required confirmation that the source is present when someone wants to upload something under the GPL.