Editing Motion compensation (section)

=== Variable block-size motion compensation ===
'''Variable block-size motion compensation''' (VBSMC) is the use of BMC with the ability for the encoder to dynamically select the size of the blocks.  When coding video, the use of larger blocks can reduce the number of bits needed to represent the motion vectors, while the use of smaller blocks can result in a smaller amount of prediction residual information to encode.  Other areas of work have examined the use of variable-shape feature metrics, beyond block boundaries, from which interframe vectors can be calculated.<ref>{{Cite book|last=Garnham|first=Nigel W.|title=Motion Compensated Video Coding - PhD Thesis|publisher=University of Nottingham|year=1995|url=http://eprints.nottingham.ac.uk/13447/1/thesis.pdf|oclc=59633188}}</ref> Older designs such as [[H.261]] and [[MPEG-1]] video typically use a fixed block size, while newer ones such as [[H.263]], [[MPEG-4 Part 2]], [[H.264/MPEG-4 AVC]], and [[VC-1]] give the encoder the ability to dynamically choose what block size will be used to represent the motion.