Select provider of libav* libraries

[Andreas Cadhalpun]

Hi Matteo,

On 23.06.2015 21:51, Matteo F. Vescovi wrote:
> On 2015-06-23 at 17:56 (CEST), Bálint Réczey wrote:
>> [...]
>> Is there anything left to be fixed before we can start the transition?
> 
> Yes, the total disappearance of FTBFS in [1].

Most of those FTBFS are completely unrelated to this transition.
Thus the affected packages will either get fixed by their maintainers
or auto-removed from testing, totally independently of the transition
to FFmpeg.
Only gpac, gst-libav1.0 and taoframework would FTBFS due to the
transition. The first two can be fixed at any time (patches exist),
but taoframework hardcodes the sonames and thus can only be updated
after the transition has started.

> If I was a Release Team member, I wouldn't allow anything to happen
> before all that mess is fixed.

Calling this a mess is a little bit exaggerated, when comparing
with previous Libav transitions...

> Feel free to retry a call for transition once the list is empty.

It's quite unreasonable to expect this list to get empty. It hasn't
been empty at any point during the past year and I don't expect
gstreamer0.10-ffmpeg will ever get fixed. (That aside, taoframework
will always be on the list, as it hardcodes the sonames...)

Patches for all FTBFS issues caused by the transition to FFmpeg
are available/trivial, so the affected packages could be NMUed,
once the transition starts.

This should be all preparation the Release Team could possibly want.

Best regards,
Andreas