In
this zip file there is also a program (not realy good, some calculation errors, higher multiplicators mean less rounding error...) that can calculate a matrix for a integer DCT. I've made some test, and the 4x4 matrix of h.26L is the best i've seen, no other matrix is more correct than this one. Ok, there is some error if you want lossless forward - inverse transform, i don't know much about float transforms, but i think the are equal or more rounding errors than using this integer dct transform.