[FFmpeg-devel] Support master branch of OpenJPEG and Grok J2K codecs

[Aaron Boxer]

Hi Ronald,


On Mon, Apr 4, 2016 at 8:34 AM, Ronald S. Bultje <rsbultje at gmail.com> wrote:

> Hi,
>
> On Mon, Apr 4, 2016 at 7:59 AM, Aaron Boxer <boxerab at gmail.com> wrote:
>
> > On Mon, Apr 4, 2016 at 7:13 AM, wm4 <nfxjfg at googlemail.com> wrote:
> >
> > > On Sun, 3 Apr 2016 17:31:25 -0400
> > > Aaron Boxer <boxerab at gmail.com> wrote:
> > >
> > > > Hi Folks,
> > > >
> > > > Here is a small patch to get FFmpeg working with both OpenJPEG master
> > and
> > > > Grok master, for J2K support.  The comment on the commit has all of
> the
> > > > details; the main change is to remove the OPJ_STATIC flag from
> > configure,
> > > > so that FFmpeg can be configured with a dynamic build of both codecs.
> > > >
> > > > I also want to reiterate that because FFmpeg can be distributed under
> > GPL
> > > > v3, and Grok is licensed under the AGPL, there are no licensing
> issues
> > > > regarding distributing FFmpeg together with Grok.
> > > >
> > > > Quoting from Wikipedia:
> > > >
> > > > "By contrast, GPLv3 and AGPLv3 each include clauses (in section 13 of
> > > each
> > > > license) that together achieve a form of mutual compatibility for the
> > two
> > > > licenses. These clauses explicitly allow the "conveying
> > > > <https://en.wiktionary.org/wiki/convey#Verb>" of a work formed by
> > > linking
> > > > code licensed under the one license against code licensed under the
> > other
> > > > license,[3]
> > > > <
> > https://en.wikipedia.org/wiki/Affero_General_Public_License#cite_note-3
> > > >
> > > > despite the licenses otherwise not allowing relicensing under the
> terms
> > > of
> > > > each other.[4]
> > > > <
> > >
> >
> https://en.wikipedia.org/wiki/Affero_General_Public_License#cite_note-fsf2-4
> > > >
> > > > In this way, the copyleft of each license is relaxed to allow
> > > distributing
> > > > such combinations.[4] "
> > > > <
> > >
> >
> https://en.wikipedia.org/wiki/Affero_General_Public_License#cite_note-fsf2-4
> > > >
> > > >
> > > > So, this patch will expand the choice of J2K codecs for all users who
> > use
> > > > FFmpeg under the GPLv3 license.
> > >
> > > AGPL is evil. That alone warrants creating a better, actually free
> > > version of the decoder.
> > >
> >
> > The only difference between AGPL and GPL is the proviso that users
> > connecting to a program using AGPL code
> > must be provided with the full source code for the program. This is to
> > close the loophole in the GPL where
> > someone can take free software, put it in the "cloud", and then treat it
> as
> > closed, non-free software, because they
> > do not have to distribute modifications.
> >
> > Please explain why you think this is a Bad Thing (TM)  ?
>
>
> Because it's a fork, not in the codebase sense but in the licensing sense,
> but the effect is the same. We will not be able to combine multiple
> branches of the fork because each of them is only compatible in its own
> direction - "LGPL code can be merged into AGPL code to create AGPL code"
> but not the other way around.
>
> That is fundamentally unfair for those of us that actually _want_ a
> LGPLv2.1-or-later codebase. Why would you get all our spoils but not the
> other way around?
>

Sorry, I was wrong in my original statements. I've learned a bit more about
how these
licenses work.

This is not a fork. FSF allows GPL 3 and AGPL 3 code to be combined.
If FFmpeg can be distributed according to GPL 3, then it can included AGPL
3 code.

Very simple.

Cheers,
Aaron



>
> Ronald
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