ing() syntax structure shall be the IdrPicFlag of the slice header(s) of the picture that has a value of frame num equal to original_frame_num (i.e., IdrPicFlag as used in clause 7.3.3.3 shall be considered equal to original_idr_flag). D.2.9 Spare picture SEI message semantics This SEI message indicates that certain slice group map units, called spare slice group map units, in one or more decoded reference pictures resemble the co-located slice group map units in a specified decoded picture called the target picture. A spare slice group map unit may be used to replace a co-located, incorrectly decoded slice group map unit, in the target picture. A decoded picture containing spare slice group map units is called a spare picture. A spare picture SEI message shall not be present in an IDR access unit. The value of the PicSizeInMapUnits variable for the target picture (as specified later in this clause) shall be equal to the value of the PicSizeInMapUnits variable for the sequence parameter set that is active when processing the spare picture SEI message. For all spare pictures identified in a spare picture SEI message, the value of frame_mbs_only_flag shall be equal to the value of frame_mbs_only_flag of the target picture in the same SEI message. The spare pictures in the SEI message are constrained as follows: If the target picture is a decoded field, all spare pictures identified in the same SEI message shall be decoded fields. Otherwise (the target picture is a decoded frame), all spare pictures identified in the same SEI message shall be decoded frames. For all spare pictures identified in a spare picture SEI message, the values of pic_width_in_mbs_minus1 pic_height_in_map_units_minus1 shall be equal to the values of pic_width_in_mbs_minus1 and pic_height_in_map_units_minus1, respectively, of the target picture in the same SEI message. The picture associated (as specified in clause 7.4.1.2.3) with this SEI message shall appear after the target picture, in decoding order. target_frame_num indicates the frame num