由于奇怪的依赖问题，无法安装 VLC 和其他程序

Question

The following packages have unmet dependencies:
 vlc : Depends: vlc-nox (= 2.1.4+git20150226+r54594+19+11~ubuntu14.04.1) but it is not going to be installed
       Depends: libsdl-image1.2 (>= 1.2.10) but it is not installable
       Depends: libtar0 but it is not installable
       Depends: libva-x11-1 (> 1.3.0~) but 1.0.15-4 is to be installed
       Depends: libva1 (> 1.3.0~) but 1.0.15-4 is to be installed
       Depends: libvlccore7 (>= 2.1.0) but it is not going to be installed
       Recommends: vlc-plugin-notify (= 2.1.4+git20150226+r54594+19+11~ubuntu14.04.1) but it is not going to be installed
       Recommends: vlc-plugin-pulse (= 2.1.4+git20150226+r54594+19+11~ubuntu14.04.1) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

我试过

1. sudo apt-get install -f
2. sudo apt-get update
3. sudo apt-get upgrade
4. sudo apt-get purge vlc vlc-nox libsdl-image1.2 libtar0 libva-x11-1 libva1 libvlccore7 vlc-plugin-notify vlc-plugin-pulse

但错误仍然存​​在。VLC 不是唯一的东西。我尝试安装的许多其他软件包都给了我类似的依赖错误，我最终放弃了安装。

我已经使用 Ubuntu 一段时间了。我只是不明白为什么会时不时发生这种情况。请帮忙 ...

编辑：

输出 apt-cache policy vlc vlc-nox libsdl-image1.2 libtar0 libva-x11-1 libva1 libvlccore7

vlc:
  Installed: (none)
  Candidate: 2.1.4+git20150226+r54594+19+11~ubuntu14.04.1
  Version table:
     2.1.4+git20150226+r54594+19+11~ubuntu14.04.1 0
        500 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ trusty/main i386 Packages
vlc-nox:
  Installed: (none)
  Candidate: 2.1.4+git20150226+r54594+19+11~ubuntu14.04.1
  Version table:
     2.1.4+git20150226+r54594+19+11~ubuntu14.04.1 0
        500 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ trusty/main i386 Packages
libsdl-image1.2:
  Installed: (none)
  Candidate: (none)
  Version table:
libtar0:
  Installed: (none)
  Candidate: (none)
  Version table:
libva-x11-1:
  Installed: (none)
  Candidate: (none)
  Version table:
libva1:
  Installed: (none)
  Candidate: (none)
  Version table:
libvlccore7:
  Installed: (none)
  Candidate: 2.1.4+git20150226+r54594+19+11~ubuntu14.04.1
  Version table:
     2.1.4+git20150226+r54594+19+11~ubuntu14.04.1 0
        500 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ trusty/main i386 Packages

Answer 1

正如您在输出中看到的那样，apt-cache policy …有些软件包没有候选安装，但事实并非如此。因此，此处的快速搜索显示，Universe 存储库中的所有包都可用，例如包libsdl-image1.2。

添加存储库：

sudo apt-add-repository universe
sudo apt-get update
sudo apt-get install vlc