1. A method of determining deblocking parameters for coded video, comprising, iteratively: performing deblocking of a decoded picture according to a deblocking vector, estimating a deblocking error from the deblocked, decoded picture, the estimated error determined from comparing the deblocked decoded picture to source picture data, if the estimated error exceeds a predetermined threshold, for each of a plurality of vector dimensions: incrementing the deblocking vector in the respective dimension, deblocking the decoded picture according to the advanced dimension, and estimating a deblocking error from the decoded picture deblocked according to the advanced dimension; revising the deblocking vector for a next iteration according to a gradient derived from the estimated deblocking errors of the vector dimensions.