Methods of encoding and decoding for video data are described for encoding or decoding coefficients for a transform unit. In particular, the significant-coefficient flags for a coefficient group are encoded and decoded based upon a context determination, and the context is determined based upon the values of neighboring flags. The neighborhood used to determine the context varies depending on whether the significant-coefficient flag to be encoded or decoded is in the two right columns or two bottom rows of the coefficient group or not. The upper-left corner may also have a different neighborhood. If the flag is in one of the two right columns or two bottom rows one of the alternative context neighborhoods is used to avoid relying on significant-coefficient flags in other coefficient groups.