Select provider of libav* libraries

[Andreas Cadhalpun]

Hi IOhannes,

On 09.06.2015 09:03, IOhannes m zmölnig (Debian/GNU) wrote:
> On 2015-06-09 06:35, Fabian Greffrath wrote:
>> Am Dienstag, den 09.06.2015, 00:26 +0200 schrieb Andreas 
>> Cadhalpun:
>>> So one can just use two directories, first run configure in both 
>>> (with the different options), then compile the GPLv2 variant, 
>>> copy the object files (without allcodecs.o) to the GPLv3 folder, 
>>> build the remaining GPLv3 de-/encoders there and link the 
>>> libraries again.
>>
>> this sounds like a good idea to start with.

I have now implemented this and it works fine.
It's in the extra branch of the ffmpeg git repository [1].

> it sounds quite fragile to me.

You have a point there, but I think it's good enough for practical use.

> while reducing build time is generally a good idea, i don't think it's
> worth the additional hassle needed to manually track whichever files
> are affected by enabling/disabling a given build option.

There is no additional hassle in tracking which files are affected by
enabling the additional codecs: These are only the files containing the
additional codecs and libavcodec/allcodecs.c, which (as the name suggests)
contains a list of all codecs. I'm quite sure this is not going to change.
If this would ever be a problem, we'll notice soon enough, because I
added an autopkgtest for the extra flavor.

> unless we hit a brick wall (e.g. cancelled builds due to timeouts on
> the build servers), i would recommend to keep it simple.

How often do you build the ffmpeg package?
Or have you ever tried to build it with qemu on, say, armel or sparc64?
If you'll ever do, I'm sure you'll appreciate that it doesn't take
twice as long as it already does.

Simon McVittie seems to think the extra flavor is not a legal problem [2]
and nobody on debian-legal objected so far.
While I'm still not totally convinced that having the extra flavor is
a good idea, I think that the way I implemented it should make everyone
here reasonable happy.
Or does someone also want a libavformat-extra flavor for the samba support?

Best regards,
Andreas


1: https://anonscm.debian.org/cgit/pkg-multimedia/ffmpeg.git/commit/?h=extra&id=1d1bf4062035d6a6c12f40fcaadbf09f74d6db1b
2: https://lists.debian.org/debian-legal/2015/06/msg00005.html