unable to play video after upgraded to ubuntu 16.04 from 14.04

[Ralf Mardorf]

On Tue, 3 May 2016 14:00:40 +0200, Ralf Mardorf wrote:
>On Tue, 3 May 2016 13:49:30 +0200, Liam Proven wrote:
>>On 29 April 2016 at 12:13, Ralf Mardorf <silver.bullet at zoho.com>
>>wrote:  
>>> On Fri, 29 Apr 2016 03:05:21 +0200, Liam Proven wrote:    
>>>>sudo apt-get clean    
>>>
>>> I wouldn't recommend to clean the complete cache, even while my
>>> cache usually is empty, but I have a backup strategy and archive the
>>> cache.    
>>
>>
>>Why not? It's just a cache. The next time you install a package, apt
>>will start rebuilding it.
>>
>>Indeed, why bother backing it up? I empty mine regularly as part of
>>routine system housekeeping. There is nothing in there you'll ever
>>need again that will not be quickly and automatically replaced,
>>surely?  
>
>It might be useful for rollback purpose. Sometimes downgrading might be
>required to fix an issue.

PS:

Perhaps unlikely for Ubuntu, but you never know. Too funny, for Arch
it's very likely that a downgrade sometimes is needed, but I usually
clean my Arch's cache, since there's a rollback repository available
and assumed the rollback repository should be broken, I still could
rebuild packages e.g. from a backup using bacman, which recreates
installed packages, or by getting it from a backup's ABS directory, a
FreeBSD alike build system. OTOH I anyway could restore my Ubuntu and
Arch from backups, without taking care about packages at all.

Usually I backup this way:

# apt-get update && apt-file update && auto-apt updatedb && auto-apt update-local && apt-get dist-upgrade && apt-get autoremove

I never used auto-apt :D, I should consider to remove it from my
upgrades. After upgrading I temporarily dump the cache in a trash
directory.

# mv -i /var/cache/apt/archives/* /root/tmp_trash/

# ls -l /root/t*
lrwxrwxrwx 1 root root 24 Sep  9  2015 /root/tmp_trash -> .local/share/Trash/files