For encoding, a frame of video data can be segregated into macroblocks, which can be segregated into slices, which in turn can be segregated into slice groups. A macroblock identifier (ID) can be associated with each of the macroblocks. When at least one slice from each of the slice groups has been encoded, the macroblock IDs associated with the encoded slices can be compared to determine an order in which the encoded slices are to be placed in an access unit for the frame. Of the encoded slices, the slice that includes the macroblock with the lowest macroblock ID will be placed in the access unit before the other encoded slices.