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2015-02-01-use-libav
  Title                     ffmpeg/libav conflict management:
                            USE=libav
  Author                    Michał Górny <mgorny@gentoo.org>
  Posted                    2015-02-01
  Revision                  2

The support for automatic choice between ffmpeg and libav is going to be
deprecated in favor of explicit choice via USE flags. This change aims
to solve multiple repeating issues, including Portage undesirably
wanting to replace one package with the other, lack of proper reverse
dependency on ffmpeg/libav upgrades and some of the hard-to-understand
upgrade failures involving blockers. It also may be used to make ffmpeg
and libav co-installable in the future.

The current USE=ffmpeg will maintain its role of enabling optional
support for ffmpeg or a compatible implementation (libav) in a package.
However, whenever appropriate additional USE=libav will be introduced to
control the preference of one implementation over the other.

Users who currently use libav need to enable USE=libav in
/etc/portage/make.conf. It should be noted that users still need to
enable USE=ffmpeg on packages with optional libav support as well.
Users who currently use ffmpeg need to take no action.

Please also note that some packages support only one of the two
implementations. An attempt to install one of those packages may result
in blockers requiring the user changes the global USE=libav state.

Please do not alter the state of 'libav' flag on a per-package basis
(e.g. via package.use). The flag needs to be set globally to have
consistent value throughout all packages. Otherwise, blockers will
prevent upgrades.

2015-04-16-ffmpeg-default
  Title                     FFmpeg default
  Author                    Ben de Groot <yngwin@gentoo.org>
  Posted                    2015-04-16
  Revision                  1

Since the choice between ffmpeg and libav has been made more
explicit, there has been a lot of discussion about what the
default implementation should be. It can be concluded that
media-video/ffmpeg has wider support, and would be somewhat
more convenient for most end-users.

For this reason the default implementation has been switched
back from media-video/libav to media-video/ffmpeg by removing
the libav useflag from the base profile.

If the libav useflag is already globally enabled or disabled
in /etc/portage/make.conf, then no further action is required.

Users who implicitly relied on libav being enabled in their
profile, and who wish to continue using libav, should enable
USE=libav in their /etc/portage/make.conf file.