[FFmpeg-devel] FFmpeg code Attribution

[Reimar Döffinger]

On Wed, Mar 23, 2016 at 03:24:47PM -0400, Aaron Boxer wrote:
> Hello Again,
> 
> I took a look at the FFmpeg j2k code. Now, I've worked with OpenJPEG for
> many years, and I would say at least 20% of the code in FFmpeg was either
> directly copied from OpenJPEG, or is very similar to OpenJPEG code.

Similarity is truly and utterly irrelevant, where it came from matters.

> I think the people who did the work on the FFmpeg codec would readily admit
> that they copied a certain amount directly from the other project.
> 
> So, I think that the OpenJPEG BSD license should appear on those files with
> copied code from OpenJPEG, to comply with the BSD license. I can list some
> of the files (there aren't many) if people are interested.

You should very much ask the authors.
Adding copyright/license from someone who is not the author is
wrong and highly objectionable (and at best marginally better than
not attributing code copied), and similarity is not enough
to conclusively show anything in most cases.
It is not that rare that there are only a few ways to do something
and it will of course look the same.
If it is copied the authors will hopefully admit to it (and hopefully
be more careful about attribution in the future).