pUnits = pic_height_in_map_units_minus1 (7-15) PicSizeInMapUnits = PicWidthInMbs * PicHeightInMapUnits (7-16) frame_mbs_only_flag equal to 0 specifies that coded pictures of the coded video sequence may either be coded fields or coded frames. frame_mbs_only_flag equal to 1 specifies that every coded picture of the coded video sequence is a coded frame containing only frame macroblocks. The allowed range of values for pic_width_in_mbs_minus1, pic_height_in_map_units_minus1, frame_mbs_only_flag is specified by constraints in Annex A. Depending on frame_mbs_only_flag, semantics are assigned to pic_height_in_map_units_minus1 as follows: If frame_mbs_only_flag is equal to 0, pic_height_in_map_units_minus1 plus 1 is the height of a field in units of macroblocks. Otherwise (frame_mbs_only_flag is equal to 1), pic_height_in_map_units_minus1 plus 1 is the height of a frame in units of macroblocks. The variable FrameHeightInMbs is derived as FrameHeightInMbs=(2-frame_mbs_only_flag)* PicHeightInMapUnits (7-17) Rec. ITU-T H.264 (01/2012) mb_adaptive_frame_field_flag equal to 0 specifies no switching between frame and field macroblocks within a picture. mnb_adaptive_frame_field_flag equalto 1specifies the possible use of switching between frame and field macroblocks within frames. When mb_adaptive_frame_field_flag is not present, it shall be inferred to be equal to 0. direct_8x8_inference_flag specifies the method used in the derivation process for luma motion vectors for B_Skip, B Direct 16x16 and B_Direct_8x8 as specified in clause 8.4.1.2. When frame_mbs_only_flag is equal to 0, direct_8x8_inference_flag shall be equal to 1. frame_cropping_flag equal to 1 specifies that the frame cropping offset parameters follow next in the sequence parameter set. frame_cropping_flag equal to 0 specifies that the frame cropping offset parameters are not present. frame_crop_left_offset,frame_crop_right_offset,frame_crop_top_offset,frame_crop_bottom_offset specify the samples of the pictures in the coded video sequence that are output from 