[Libav-user] Licensing Issues with Modifying libavformat/libavformat.av

[Phil Turmel]

On 06/17/2016 09:46 AM, billcame at comcast.net wrote:
> I am compiling FFmpeg for both Mac and Windows.  For Mac, I can compile
> the source unmodified as is and use it.  For Windows, I have to modify
> libavformat/libavformat.av in order to allow 2 functions to be exported
> in avformat.dll.  This is the only modification.  The two functions are
> accessible from the unmodified source code compiled as dylibs.
> 
> Is this considered a configuration option while building?  I am
> concerned about licensing issues modifying FFmpeg source.  When FFmpeg
> is configured, it is compiled without "--enable-gpl" and without
> "--enable-nonfree" but with "--enable-shared".

Based on that, you're fine as long as you host your modified source tree
for anyone who gets your binaries (or just include source in your
distribution method) and allow your users to modify further and
substitute their dll.