Cyberlink Powerdvd have a feature called "software decoding with truetheater enhancement". For example: "to up scale the original video to a higher resolution version, which is sharper and artifact-free. TrueTheater HD is capable of boosting 480p video to 1080p."
How can I have these features in MPlayer? Is there any way?
Well you can go to Prefences -> Video -> and enable post-processing by default with max quality, deinterlacing and choose driver for rendering. The best driver for rendering is probably madvr, but you can't run it on ubuntu. I think gl would be good enough and will use (probably) gpu acceleration, so you'll have a speed-up.
