Re: [gentoo-dev] Review: USE=libav news item

[Peter Stuge]

Michał Górny wrote:
> Title: USE=libav introduction
> Author: Micha?? G??rny <mgorny@g.o>

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> Content-Type: text/plain
> Posted: 2015-01-yy
> Revision: 1
> News-Item-Format: 1.0
> Display-If-Installed: media-video/ffmpeg
> Display-If-Installed: media-video/libav
>
> 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, subslot upgrade issues
> and some of the hard-to-understand blocker issues.
>
> 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 libav over ffmpeg.
>
> Users who currently use libav (the Gentoo default) do not have to
> perform any action since USE=libav is enabled by default. It should be
> noted that those users will need to enable USE=ffmpeg on packages with
> optional libav support as well.

So far so good.

> Users who want to use the ffmpeg fork instead need to specify USE=-libav
> explicitly.

"the ffmpeg fork" above is very confusing because libav is the ffmpeg
fork, and I think what you mean here is simply "ffmpeg". I suggest:

Users who want to use ffmpeg rather than libav where that is possible
instead need to specify USE=-libav explicitly.


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

This isn't completely accurate.. It's enough to change USE=libav for
the affected packages. I'm afraid I can't offer a wording suggestion
on this one. :\


//Peter