motion estimation/search algorithms

[cuban]

I'm interested in motion search algorithms (especially ones with sub-pel accuracy), and i'm looking for some detailed specifications (not just ideas). I found some articles on google, but that is still not satifying me. For example, i haven't found anythig useful about uneven multi hex algorithm (i know it's implemented in x264). If anyone has any kind of info i will be grateful.

The reason why i'm looking for these algorithms is that i will have to implement a motion compensated deinterlacer (for my studies).

Of course, i found, that IEEE has tons of papers about it, but unfortunatelly i dont have their subscription :(

greets :)

[Guest]

Check your PM.

[imcold]

Isn't subpel motion search accuracy archieved by "whole pel" searching on upsampled image?

[cuban]

Isn't subpel motion search accuracy archieved by "whole pel" searching on upsampled image?

Well, there are different kinds of subpel motion search algorithms. There are matching based techinques, gradient based or even spatio-temporal filters based... When we think about subpel accuracy, there is some kind of "upsampling", but thats not that easy. There are lots of constrains for motion vectors that must be satisfied. For example, in x264 encoder there are 7 various subpixel refinement algorithms (used with the 1pel accuracy motion search alg) .