In the JEM, there are two affine motion modes: AF_INTER mode and AF_MERGE mode. For CUs with both width and height larger than 8, AF_INTER mode can be applied. An affine flag in CU level is signaled in the bitstream to indicate whether AF_INTER mode is used. In the AF_INTER mode, a candidate list with motion vector pair {(v0, v1)|v0={vA, vB, vc}, v1={vD,vE}} is constructed using the neighboring blocks.
In JEM, the non-merge affine mode can be used only when the width and the height of the current block are both larger than 8; the merge affine mode can be used only when the area (i.e. width×height) of the current block is not smaller than 64.