1. A method for detecting block artifacts, comprising: identifying a plurality of overlapping blocks in a picture from a sequence of moving video pictures with respect to a current block, where each one of said plurality of overlapping blocks covers a portion of the current block and a portion of an adjacent block; transforming at least one of the plurality of overlapping blocks into respective transform coefficients corresponding to at least one of a luminance component and a chrominance component; identifying a block artifact for the at least one of the plurality of overlapping blocks when a coefficient of said respective transform coefficients corresponding to the at least one of the plurality of overlapping blocks is larger than a value; determining a blockiness value for a block boundary between a first block and a second block in the picture, including: accessing lines of pixels, each of the lines of pixels having pixels from the first block and the second block, determining a respective filtered value for each of the lines of pixels, and determining the blockiness value for the block boundary in response to the filtered values, the determining the blockiness value excluding a minimum or a maximum of the filtered values; and determining an artifact strength of the block artifact responsive to at least one of the identifying a block artifact and the determined blockiness value.