[Exherbo-dev] [RFC] || ( ) dependencies and virtuals

Johannes Nixdorf mixi at shadowice.org
Sat Jan 4 16:00:59 UTC 2014

On Sat, Jan 04, 2014 at 12:00:04AM +0100, Quentin Glidic wrote:
> On 02/01/2014 22:39, Bo Ørsted Andresen wrote:
> >On Thu, 02 Jan 2014 22:33:20 +0100
> >Quentin Glidic <sardemff7 at exherbo.org> wrote:
> >>It would be the build-time vs. runtime aspect of the := dependency
> >>that would matter here. I would go with :libav and :ffmpeg
> >>(inter-blocked) so changing slot would mean changing implementation,
> >>while forcing a rebuild.
> >
> >So how about versioning of the virtuals?
> What do you mean? Versions would be library-based. The dependency
> would look like "virtual/ffmpeg:=[>=${library_version}]".

How would ${library_version} look like? ffmpeg and libav consist of many
different libraries with different versions and a specific version might
mean something completely different for ffmpeg and libav.

For example the minor version of libavformat was bumped from 9 to 10 in
libav in the commit 435214a757fc71d1680b12d6f930254cab3935d1 "Add an HDS
live fragmenting muxer". The same commit later landed in ffmpeg with
641358addcffe0cca55c547316781b11e9315dbc and they bumped the libavformat
minor version in the commit from 20 to 21.

To quote mpv's source code again:
# libavfilter as it can be used by vf_lavfi is 3.45.101 in FFmpeg, and
# 3.5.0 in Libav. Completely useless version numbers.

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