1. A method for decoding video data, the method comprising: determining that a coding unit (CU) in a B slice is partitioned into one or more prediction units (PUs); and for at least one of the PUs of the CU: determining, based on a size characteristic of the PU, that the PU is restricted to uni-directional inter prediction; and parsing, from a bitstream, an inter prediction mode indicator for the PU, wherein when the PU is restricted to uni-directional inter prediction, the inter prediction mode indicator is able to indicate that the PU is either uni-directionally inter predicted based on a list 0 or uni-directionally inter predicted based on a list 1 , wherein when the PU is not restricted to uni-directional inter prediction, the inter prediction mode indicator is able to indicate the PU is either uni-directionally inter predicted based on the list 0 , uni-directionally inter predicted based on the list 1 , or bi-directionally predicted.