In recent days i've been looking into a way to mix together MP3 files at the point of upload to a website, which is hosted on a linux machine.
So far, thanks to the community, i've learned that using SoX over the command line is probably the most efficient way to actually produce a mixed file from two sources. I have also discovered that Audacity may also be useable for the purpose.
Unfortunately, both of these programs being free - they do not support the MP3 format due to legal issues around patents and licensing. I know that support can be added with LAME, however this still remains illegal because LAME is also free and is not licensed by the patent owners.
So I'm looking for a way to add MP3 encoder/decoder support to Sox, Audacity or a similar command-line enabled program, so that it can be used legally within a commercial website. Searches have once again come up blank, does anyone know of a solution please?
You can simply use the LAME plugin, but purchase a patent license covering your use of the patented technology. mp3licensing.com has further information, including the royalty rates.
It appears that the last of the known MP3 patents will expire in the US on December 30, 2017.