[FFmpeg-devel] [PATCH] Dynamic plugins loading

[Reimar Döffinger]

On Sat, Nov 06, 2010 at 12:30:36PM +0200, Felipe Contreras wrote:
> On Sat, Nov 6, 2010 at 11:47 AM, Reimar D?ffinger
> <Reimar.Doeffinger at gmx.de> wrote:
> > On Sat, Nov 06, 2010 at 11:18:54AM +0200, Felipe Contreras wrote:
> >> FFmpeg's lack of dynamic plugin loading prevents it from getting into
> >> the Fedora distribution. Period.
> >
> >> So we come again to the same: you don't care about Fedora. Fedora has
> >> a philosophy, and that's that.
> >>
> >> Basically what you are saying is that Fedora needs to change their
> >> philosophy in order to conform to FFmpeg.
> >
> > Well, I think we are still trying to figure out the philosophy,
> > sometimes it is claimed to be "no patents" then it seems to be more
> > like "no patents unless those we for some reason considered safe" or
> > possibly "let's better not look, we might find a patent issue" and
> > now according to you it's not related to patents but it's just
> > that "dynamic plugin loading" is an absolute requirement.
> 
> You are mixing everything. It's very simple; FFmpeg has code with
> patents claimed by MPEG LA and other parties... that can't go into
> Fedora, but people should be able to install that support from a third
> party (rpmfusion.org).
> 
> The only solution provided so far that is transparent to the end-user
> is dynamic plug-in loading.

No, that is no solution. Packages from different source that depend
on internal APIs for which we guarantee no compatibility is a horror
that Debian users have experienced enough, and here the involved
dynamic libs were only different libav* versions and MPlayer.
I see no reason why this wouldn't be far worse for plug-ins.

> However, I just heard in fedora-devel that
> it might be possible to use a SONAME trick which seems to be used for
> nvidia-libGL.so. A hack, but there's no better option for some
> libraries.

I do not know about better, but there are sure other options.
First, you say that FFmpeg is not in Fedora at all, which needs
to be "solved" first, otherwise we might just waste our time,
related to this:

> libvpx contains a _single_ codec that is claimed to be public domain,
> there's no need for plugins.

What is the difference to FFmpeg only compiled with VP8 decoder support,
which according to you is not in Fedora either?
Next, apt at least provides a way to select a certain package from a certain
source, so e.g. if someone has rpmfusion enabled they'd get the "full" FFmpeg,
otherwise the "basic". This has some issues, but sure is possible.
Then there's the option of adding proper support for this. I mean a lot of
programs and even libraries can be built with very different configurations
(e.g. I think libSDL can be built with framebuffer-only or X support, if your
packaging system does not support these kinds of alternatives everyone needs
to install X even if they only want to use a framebuffer SDL program).
So it seems really questionable to me that FFmpeg is the place that needs fixing.

Reimar