ed slice extension NAL units with svc_extension_flag equal to 1 are also referred to as coded slice in scalable extension NAL units and coded slice extension NAL units with SVC_extension_flag equal to 0 are also referred to as coded slice MVC extension NAL units. Rec. ITU-T H.264 (01/2012) 7.4.3 Slice header semantics When present, the value of the slice header syntax elements pic_parameter_set_id, frame num, field_pic_flag, bottom_field_flag, idr_pic_id, pic_order_cnt_lsb, delta_pic_order_cnt_bottom, delta_pic_order_cnt[0] delta_pic_order_cnt 1], sp_for_switch_flag, and slice_group_change_cycle shall be the same in all slice headers of a coded picture. first_mb_in_slice specifies the address of the first macroblock in the slice. When arbitrary slice order is not allowed as specified in Annex A, the value of first mb in slice is constrained as follows: If separate_colour_plane_flag is equal to 0, the value of first mb in slice shall not be less than the value of first mb in slice for any other slice of the current picture that precedes the current slice in decoding order. Otherwise (separate_colour_plane_flagise equal to 1), the value of first_mb in slice shall not be less than the value of first mb in for any other slice of the current picture that precedes the current slice in decoding order and has the same value of colour_plane_id. The first macroblock address of the slice is derived as follows: If MbaffFrameFlag is equal to 0, first_mb_in_slice is the macroblock address of the first macroblock in the slice, and first mb in slice shall be in the range of 0 to PicSizeInMbs - 1, inclusive. Otherwise (MbaffFrameFlag is equal to 1), first mb in slice * 2 is the macroblock address of the first macroblock in the slice, which is the top macroblock of the first macroblock pair in the slice, and first mb in slice shall be in the range of 0 to PicSizeInMbs / 2 - 1, inclusive. slice_type specifies the coding type of the slice according to Table 7-6. Table 7-6 - Name association to slice_type slice_type Name of slice_typ