[FFmpeg-devel] [RFC] Cherry picks vs merges

[Michael Niedermayer]

Hi Remi

On Mon, Jun 02, 2025 at 06:38:54PM +0300, Rémi Denis-Courmont wrote:
[...]
> >And the "explicit license notice" you refer to is this:
> >
> >"All Librempeg modifications, and any new files not available in FFmpeg, are licensed under GPL v2,
> > unless stated otherwise."
> 
> So, which of his "modifications" (commits) have an explicit statement "otherwise"?

I see this:

commit 3ff6d301b27965b23ae5cf5211920ee16d6671c2
Author: Anton Khirnov <anton at khirnov.net>
Date:   Thu Oct 24 08:37:11 2024 +0200

    lavfi: add frame threading infrastructure

    Code under AGPL, use --enable-agpl to enable.

this code also has AGPL headers in source, there is no ambiguity here


[...]
> 
> >And it IS stated otherwise in these files by the license header in these
> >files.
> 
> It is stated that the original files were under the LGPL (or GPL), nothing else.

Many new codecs and filters where added by Paul, and he used standard LGPL license
headers for them.
Thats not a "modified existing file with LGPL" case
its genuinely new files where LGPL headers where used.


[...]

> Fortunately, the record of changes does in fact exists: the Librempeg git repo. But that being the case, we can't argue that you didn't notice that the modifications didn't have a statement "otherwise".

The files do have statements "otherwise", in the form of the LGPL license header


> 
> And sure, that's just my interpretations, but what do you think Paul *intended* here? If it come to that, the court, or more likely, FFmpeg downstreams and reverse dependencies, will probably base their decision on Paul's inferred intent, not mine, but also not yours.

IANAL but according to the principle of contra proferentem, in case of ambiguity
a clause should be interpreted against the party who wrote the clause not in favor.

That said, there is no real ambiguity, its LGPL headers, there is nothing that
REMOVES this license. The statement ADDS a GPL v2 license.
The "unless stated otherwise" excempts the AGPL code from receiving the GPL v2

That said, iam not sure how wise it is to discuss legal interpretations in public.
Generally lawyers recommand against such things.


[...]

> In fact, I believe FFmpeg itself contains some code that was relicensed from liberal licenses and yet we didn't systematically feed the changes back, did we?

If we did not, we should do that.


> 
> >You knew i was working on this and i would have appreciated a private
> >message over a public accusation
> 
> That's not fair.

all members of fflabs where aware of it as i asked about the license situation it in the private
fflabs IRC channel. I asked there because fflabs/jb has a lawyer

[...]

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you drop bombs on a foreign country and kill a hundred thousand
innocent people, expect your government to call the consequence
"unprovoked inhuman terrorist attacks" and use it to justify dropping
more bombs and killing more people. The technology changed, the idea is old.
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