Hmmm. Well, all I can tell from your posts is that you had an unspecified problem, you enabled and installed VLC and Clementine and, possibly, something else from the multimedia repo, and someone on the Videolan forum says you shouldn't use the multimedia repo.
First of all, if you are running Wheezy,
there is no stable backports for it. Stable backports is for the stable version of Debian, which is currently Squeeze. Installing anything to Wheezy from backports would be a step backwards in package versions. Until Wheezy moves out of testing and becomes the new stable branch, there will be no backports repo for it.
Second, it's easy for a first party to blame a second party for using "the wrong repository", especially when no troubleshooting has been attempted and very little is known about the second party's installation or problems. The libavutil "problem" is from a January 2010 post. A lot has changed since then. I do realize the thread you pointed to goes up through February of 2013. Still, I see no one in that thread has attempted to get to the bottom of posted problems by attenpting to do basic troubleshooting. Maybe that's not the focus of the Videolan forum. I don't know.
Third, the multimedia repo is one of the
first additional repos I
always add to my Debian Wheezy sources list. The reason is that the repo has more up-to-date codecs that the "official" repos don't have. The multimedia repo also has some codecs that the "official" repos just don't have, at all, period. libdvdcss comes to mind. In any event, I've never had a dependency problem or non-functioning application problem as a result of doing so. The DebWeb and DebRazor respins I've done both have the multimedia repo enabled by default in the sources list. The Deb-e17 respin I'll be publishing today or tomorrow also has it enabled.
Just as a test, I played an mp4 video in VLC in the DebWeb respin.
No problems, no stuttering, no error messages and no crashes. The VLC version?
I then tried playing an mp3.
The only problem there is that I now want to listen to the entire Back in Black album again. For the umpteenth time. I've discovered with using the package manager GUI, Synaptic, that sometimes apparent package conflicts are not really conflicts at all. Sometimes, the package list just needs to be updated by clicking the Update button. Sometimes, there may be "cruft" left over from previous uninstalls. If there are any packages in the auto-removable section, I remove them. All of them. If one or more are packages I actually want installed, I make a note of them and reinstall after having refreshed the package list again. Afterwards, they seldom show as auto-removable. The same goes for old configurations from removing packages. There's a section in Synaptic for removable configuration files, and I remove any found there.
I do tend to get long-winded. But, to summarize, not all dependency problems are caused by the wrong choice of repositories. Neither are all application problems. It's easier to point a finger at the repo used than it is to get to the bottom of a user's problems. The problems a user encounters must be spelled out, specifically, before anyone can offer meaningful help in solving said problems.