Provided are techniques for low complexity video coding. For example, a video coder may be configured to calculate a first sum of absolute difference (SAD) value between a CU block and a corresponding block in a reference frame for the largest coding unit (LCU). The video coder may define conditions (e.g., background and/or homogeneous conditions) for the branching based at least in part on the first SAD value. The video coder may also determine the branching based on detecting the background or homogeneous condition, the branching including a first branch corresponding to both a first CU size of the CU block and a second CU size of a sub-block of the CU block. The video coder may then set the first branch to correspond to the first CU size, if the first CU size or the second CU size satisfies the background condition.