1

Smplayer is the best frontend for mplayer which in turn is the best video player.

Smplayer should be the primary video player in KDE.

Due to patent issues I do not think this is feasible, but I am not sure.

Though it might be shipped with many distro's the mPlayer back end is not because of patent issues, so making a non-functioning (at installation) player the default would not make sense

I found the only problem with CSS decryption, but I'm not quite sure.

Is the choice [and information on patents] during the installation would be possible?

mplayer also supports a number of patented audio and video codecs. I am not sure if it is possible to build mplayer without them.

Whatever the case, this is not going to happen because KDE's focus is on phonon. Unless smplayer changes to use phonon the idea will not implemented.

Instead of Smplayer why dont make vlc the default video player?
Using it as a phonom back-end and also replace the dragon player with vlc gui I think will be better. VLC is really a nice player.

I think the plan is to make the VLC phonon backend the default one. But once again, they are not going to make VLC itself the default video player unless it becomes a KDE project. Distributions are free to make it as such, but being the default would imply it is part of KDE SC, which VLC is not and almost certainly never will be.

Well, after many years of not using the SMPlayer, I downloaded the latest version 18.2.2, and as I can see they managed to solve old bugs from all previous version.. Finally..

I believe Ubuntu 12.04 currently does not follow the global defaults set under System Settings->Details->Default applications My Lowe's Life.

What you can do is go to that video's location in the File Manager, right click, then select Properties, go to the Open with tab, select the application you want (in your case that would be SMPlayer), the click Set as default.