Video Playback Laggy (VLC, .avi or .mkv)

[Dubslow]

Hey guys,
Just got a bunch of movies from a friend. Tried to play a HD Star Wars .mkv with VLC, but it was pretty clearly lagging. Then I tried a Disney movie from 1963 as a .avi, but that appeared to lag too, and I don't think it's the movie. I'm pretty positive that I have the capability to play HD movies. I can play a 256x256 Minecraft texture pack still at maxed out graphics with no lag.

AMD Phenom II X6 1055T Thuban 2.8GHz 6 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Six-Core Desktop Processor HDT55TFBGRBOX

GeForce GTX 460 (Fermi) 768MB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card

8 GB of RAM

I have installed the restricted NVIDIA drivers as Ubuntu requested on install.

(Still running 10.10 Maverick)

What can I do? Am I missing some codecs?

[handy]

You've done the Restricted Formats thing:

https://help.ubuntu.com/community/Re...cted%20Formats

& it sounds like you must already have libdvdcss2 & such:

https://help.ubuntu.com/community/Medibuntu

[Dubslow]

I got the dvd thing working (I had previously tried to install that package with apt-get but it hadn't worked) but I already had the restricted extras. As for the .mkv, it went much better after I killed the Minecraft server I had running, as well as compiz. Compiz was taking half of my CPU, and killing that made the video run fine. On the other hand, it seems like I should be able to run compiz and HD .mkv's at the same time.

[handy]

I haven't had problems with watching videos for very many months now. & I have been using the -git AMD/ATi open-source driver stack & kernel now for well over 18 months.

Though, I must say, I NEVER use Compiz or the like, for two reasons: Primarily I don't use a DE, & I'm not interested in those pretties. Secondarily, such 3D desktop stuff just seems like a terribly inefficient waste of system resources to me.

When I say that, I'm not making a personal judgement, it is just the way I see it, & in reality I'm just a boring old fart.