My os: Linux Mint 17.1 (x64) + CinnamonI tried to make my linux play wma files and i broke something, because i can't play any videos now. What i tried:deleting ~/.gstreamer-1.0 folderrunning sudo /usr/share/doc/libdvdread4/install-css.sh (maybe this broke my system?)trying to install some libraries through apt-get (for example those having libavcodec in name and possibly others)Now when i try to run mplayer i get the error:> mplayermplayer: error while loading shared libraries: libavcodec.so.54: cannot open shared object file: No such file or directoryOther players (vlc) don't work either. So i tried updating my system. sudo apt-get update throwed some errors:(...)Err http://ppa.launchpad.net trusty/main Sources  404  Not FoundGet:21 http://packages.linuxmint.com rebecca/upstream i386 Packages [30,0 kB]Err http://ppa.launchpad.net trusty/main amd64 Packages  404  Not FoundHit http://archive.ubuntu.com trusty-updates/restricted Translation-enErr http://ppa.launchpad.net trusty/main i386 Packages  404  Not Found(...)W: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/dists/trusty/main/source/Sources  404  Not FoundW: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/dists/trusty/main/binary-amd64/Packages  404  Not FoundW: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/dists/trusty/main/binary-i386/Packages  404  Not FoundE: Some index files failed to download. They have been ignored, or old ones used instead.sudo apt-get upgrade didn't work at all:Reading package lists...Building dependency tree...Reading state information...You might want to run 'apt-get -f install' to correct these.The following packages have unmet dependencies: audacity : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                     libavcodec-extra-54 (>= 6:9.13) but it is not installed ffmpeg : Depends: libavcodec54 (>= 7:1.2.5~) but it is not installed or                   libavcodec-extra-54 (>= 7:1.2.5~) but it is not installed gstreamer1.0-libav : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                               libavcodec-extra-54 (>= 6:9.13) but it is not installed libavdevice53 : Depends: libavcodec54 (>= 7:1.2.5~) but it is not installed or                          libavcodec-extra-54 (>= 7:1.2.5~) but it is not installed libavfilter3 : Depends: libavcodec54 (>= 7:1.2.5~) but it is not installed or                         libavcodec-extra-54 (>= 7:1.2.5~) but it is not installed libavformat54 : Depends: libavcodec54 (>= 7:1.2.5~) but it is not installed or                          libavcodec-extra-54 (>= 7:1.2.5~) but it is not installed libchromaprint0 : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                            libavcodec-extra-54 (>= 6:9.10) but it is not installed libopencv-highgui2.4 : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                                 libavcodec-extra-54 (>= 6:9.10) but it is not installed mencoder : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                     libavcodec-extra-54 (>= 6:9.11) but it is not installed mplayer : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                    libavcodec-extra-54 (>= 6:9.11) but it is not installed vlc-nox : Depends: libavcodec54 (>= 6:9.1-1) but it is not installed or                    libavcodec-extra-54 (>= 6:9.18) but it is not installedE: Unmet dependencies. Try using -f.then i tried sudo apt-get -f install:Reading package lists... DoneBuilding dependency treeReading state information... DoneCorrecting dependencies... DoneThe following packages were automatically installed and are no longer required:folder-color-switcher gir1.2-nemo-3.0 nemo-emblemsnemo-folder-color-switcher python-nemo python-psutilUse 'apt-get autoremove' to remove them.The following extra packages will be installed:libavcodec54The following NEW packages will be installed:libavcodec540 upgraded, 1 newly installed, 0 to remove and 13 not upgraded.Need to get 2715 kB of archives.After this operation, 7309 kB of additional disk space will be used.Do you want to continue? [Y/n] YWARNING: The following packages cannot be authenticated!libavcodec54Install these packages without verification? [y/N] yErr http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/ trusty/main libavcodec54 amd64 7:1.2.6-1~trusty1404  Not FoundE: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/pool/main/f/ffmpeg/libavcodec54_1.2.6-1~trusty1_amd64.deb  404  Not FoundE: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?Then i run sudo apt-get update --fix-missing which gave me similar errors to sudo apt-get update.I also tried synaptic package manager, which during start stated You have 11 broken packages on your system!.... I tried Edit => Fix Broken Packages which appeared to do nothing (not even throw an error).  Then i chose Broken dependencies filter, marked all packages there for reinstall and after several screens i got errors:W: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/pool/main/f/ffmpeg/libavcodec54_1.2.6-1~trusty1_amd64.deb  404  Not FoundW: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/pool/main/f/ffmpeg/ffmpeg_1.2.6-1~trusty1_amd64.deb  404  Not FoundW: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/pool/main/f/ffmpeg/libavdevice53_1.2.6-1~trusty1_amd64.deb  404  Not FoundW: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/pool/main/f/ffmpeg/libavfilter3_1.2.6-1~trusty1_amd64.deb  404  Not FoundW: Failed to fetch http://ppa.launchpad.net/jon-severinsson/ffmpeg/ubuntu/pool/main/f/ffmpeg/libavformat54_1.2.6-1~trusty1_amd64.deb  404  Not FoundSo anyone knows what/how did i break and how can i fix it? Thank you.
Broken Packages problem
linux mint
I fixed it like this:Open Software SourcesIn PPA tab search for entries with ffmpeg in name and remove all of themThen run these commands in terminal (they update/clean whole system. If you don't want to upgrade distro you may omit the line with dist-upgrade part): sudo apt-get -f installsudo apt-get updatesudo apt-get upgradesudo apt-get dist-upgradesudo apt-get autoremovesudo apt-get autocleansudo apt-get cleanOptionally install mplayer and/or vlc for playing video/audio files:  sudo apt-get install mplayersudo apt-get install vlcand everything works as usual again.