As part of a video encoding or decoding operation on video data, a video coder performs a coding operation for a current video unit of the video data. As part of performing the coding operation for the current video unit, the video coder determines the availabilities of one or more video units that neighbor the current video unit. In order to determine the availability of a video unit that neighbors the current video unit, the video coder identifies, based on availabilities of video units that neighbor a parent video unit of the current video unit, an entry in a lookup table. The identified entry indicates the availability of the video unit that neighbors the current video unit. The video coder then performs a coding operation on the current video unit based on whether the video unit that neighbors the current video unit is available.