Select provider of libav* libraries

[Andreas Cadhalpun]

Hi Reinhard,

On 07.06.2015 22:08, Reinhard Tartler wrote:
> On Sat, Jun 6, 2015 at 3:05 PM, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com <mailto:andreas.cadhalpun at googlemail.com>> wrote:
>> The problem I see is run-time linking a GPLv2-only program with a GPLv3+
>> library. I think this makes such a Live DVD undistributable, because the
>> licenses are not compatible.
> 
> The problem is that neither of the involved licenses talk about "run-time"
> nor "compile-time" linking. The point is the creation of a derived work.

Yes.

> You are right that in this situation, it is not clear at all of the live cd
> is a derived work, or a compilation of independent works. The former would
> be rather problematic, but my understanding is that a live cd is rather
> the latter.

OK, in that case build-conflicts from the GPLv2-only programs on
libavcodec-extra* should be totally sufficient.

>>>> Would it be hard to patch the build system?
>>>
>>> To do what exactly?
>>
>> To implement this in a dh7-style debian/rules file.
> 
> I do appreciate the dh7-style brevity for simple packages. But for
> complex packages, such as libav that makes use of multiple compilation
> passes, I found the provided abstractions that make it so attractive
> to use get quickly in the way.

I don't think so. Since in the dh7-style everything can be overridden,
it is just as flexible as the pre-dh7-style, but contains less boilerplate.

>> Not having the libavcodec-extra flavor is not only a regression
>> (having no AMR encoder), but also an improvement (simpler debian/rules,
>> no license incompatibility to worry about, faster build, ...).
>> I happen to think the improvement factor is bigger than the regression
>> factor, but others may disagree.
> 
> 
> As Fabian points out, it is not only AMR, but (currently) also libvo-aacenc.

I think the native aac encoder is better than the libvo-aacenc encoder, but
if we provide a libavcodec-extra flavor, we can enable that as well.

Best regards,
Andreas

1: https://lists.debian.org/debian-legal/2015/06/msg00005.html