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

Ronald S. Bultje rsbultje at gmail.com
Mon Apr 4 14:34:39 CEST 2016


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?

Ronald


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