Global Motion Compensation (GMC)
Global motion compensation (GMC) helps in zooming (bringing the camera closer) and panning (swivelling the camera), if the objects remain static in type and only change in size and position within an image. Activation of GMC is advisable if nature films or landscape documentation are to be compressed.
Quarter Pixel (QP)
Quarter pel or quarter pixel affects the precision in filtering of macro blocks. DivX 4 works with half pel (1.5, 1.5); 1.25, 1.75, etc. are possible starting with DivX 5. Conventional division of an image into macro blocks is refined on the basis of integers - 16x16 or 8x8 - using the supplementary information from what are known as virtual blocks. This allows the motions of objects in images to be reproduced more realistically.
BD, GMC And QP - Not In The Standard Version
QP, GMC and BD cannot be used for encoding in the standard version. But decoding is still possible, even if these functions were used for encoding.
