Difference between MPEG-4 AVC and MPEG-4 ASP (DivX)

The main difference between MPEG-4 AVC and MPEG-4 ASP lies in the way each standard encodes and decodes video. AVC supports variable motion compensation blocks sizes ranging from 16x16 (macroblocks) to 4x4 (sub blocks) luminance samples with many options between the two. The ASP standard is fixed at 16x16 blocks, which inhibits a smooth transaction across the pixels, and thus lowers the viewing quality. Other differences can be viewed in the attached chart (click link above).