On 2016-11-28 at 01:10, Charlie wrote: > On Mon, 28 Nov 2016 00:19:38 -0500 The Wanderer sent: > > <snip> > >> I have - different from your own: >>> >>> $ apt-cache policy libavutil55 >>> libavutil55: >>> Installed: 10:3.1.2-dmo2 >>> Candidate: 10:3.1.2-dmo2 >>> Version table: >>> *** 10:3.1.2-dmo2 100 >>> 100 /var/lib/dpkg/status >>> 7:3.2-2 500 >>> 500 http://ftp.us.debian.org/debian stretch/main amd64 >>> Packages >> >> This is almost certainly your problem. The version of libavutil which >> you have is from a different source, with a higher epoch version but a >> lower upstream version, and is no longer available from your selected >> repositories. In particular, it is not the same version as your other >> libav* libraries (as the snipped version information for libavformat >> indicates), and that mismatch is probably the source of the problem. >> >> Do you have any idea how this mismatched package version may have come >> about? >> >> I recommend that you explicitly install the "lower" version listed >> here (7:3.2-2), and see if your problem goes away. >> >> I don't know what tools you normally use for package installation and >> upgrade, but I would do that with the following command (in a root >> terminal): >> >> apt-get install libavutil55=7:3.2-2 > > After contemplation, my reply is: > > I'm on a different machine now, at a different place when sending this. > > I only ever use apt-get for updates, upgrades, installs and purges. > > But before I left that machine I attempted your excellent suggestion > and received this error message: > > The following packages have unmet dependencies: > libswresample2 : Depends: libavutil55 (>= 10:3.1.2) but 7:3.2-2 is to > be installed > E: Error, pkgProblemResolver::Resolve generated breaks, this may be > caused by held packages. > > I assume that I might have missed a bug report on a update/upgrade? So > I will just have to purge libswresample2, and libavutil55 (>= 10:3.1.2) Actually, it looks like libswresample2 has the same problem: the installed version has a higher epoch but lower actual version. My best guess is that at some point, you installed some package from a different repository, which depended on these higher-epoch package versions, and thus got them upgraded without upgrading the rest of your libav* package ecosystem. I would just add libswresample2 to your explicit-version install command, and see what result you get. It may give further unmet-dependencies errors; if you pursue the cascade far enough (I'd advise checking each new package with 'apt-cache policy' to see available versions before proceeding), you may be able to identify the package(s) which depend or depended on the higher-epoch libav* packages to begin with. (Purging the libav* packages will probably result in trying to uninstall various packages which depend on them, possibly including quite a few things you may actually want. Although you could always do that and reinstall the appropriate packages afterwards, "down"grading is almost certainly the superior solution.) -- The Wanderer The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. -- George Bernard Shaw
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