Video B H264 ROI region3 range configure register.
| X | Configures the horizontal start macroblocks of region 3 in Video B. |
| Y | Configures the vertical start macroblocks of region 3 in Video B. |
| X_LEN | Configures the number of macroblocks in horizontal direction of the region 3 in video B. |
| Y_LEN | Configures the number of macroblocks in vertical direction of the region 3 in video B. |
| EN | Configures whether or not to open Video B ROI of region 3 .\0:Close ROI\1:Open ROI. |