I've done both your suggestions, the first results in something like this:
ubuntu:~$ sudo apt-get install libdbus-1-3
Reading package lists... Done
Building dependency tree
Reading state information... Done
libdbus-1-3 is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
ubuntu:~$ sudo apt-get install tvheadend
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
tvheadend : Depends: libdbus-1-3 (>= 1.9.14) but 1.6.18-0ubuntu4.4 is to be installed
E: Unable to correct problems, you have held broken packages.
can I uninstall somehow libdbus-1-3 and install it again?
The second has the following output:
(long list of updated/checked packages)
Reading package lists... Done
ubuntu:~$ sudo apt-get autoclean
Reading package lists... Done
Building dependency tree
Reading state information... Done
ubuntu:~$ sudo apt-get clean
ubuntu:~$ sudo apt-get autoremove
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
ubuntu:~$