Not long ago I read (I think on Ray Kurtzviel's blog) that software has been developed that will raise resolution in music and graphics samples. That is, take a sample with low resolution and infer a higher resolution output. That, of course was a lab thing. I was just wondering if its available yet commercially.
There are some smart upscaling software and hardware devices for images. Most here would agree that expensive hardware scaling with a Teranex or similar gives the best results. Others swear by the upscaling in the Kona cards ans software like Innobits Video Purifier do high quality software upscaling with some smart noise reduction.
With sound it is possible to use high bit rate floating point processing to apply EQ and other processing without causing distortions introduced by rounding errors. This can improve the sound but the original frequency response and distortion is not changed.