marked as "reference base picture". long_term_base_pic_num is used (with memory_management_base_control_operationequal to 2) to mark a long-term reference base picture as "unused for reference". When the associated nemory_management_base_control_operation is processed by the decoding process, long_term_base_pic_num shall be equal to a long-term picture number assigned to one of the reference pictures marked as "used for long-term reference" and as "reference base picture". The resulting long-term picture number is constrained as follows: If field_pic_flag is equal to 0, the resulting long-term picture number shall be one of the set of long-term picture numbers assigned to reference frames or complementary reference field pairs marked as "reference base picture". NOTE 3 - When field_pic_flag is equal to 0, the resulting long-term picture number must be a long-term picture number assigned to a complementary reference field pair in which both fields are marked as "used for long-term reference" and "reference base picture" or a reference frame in which both fields are marked as "used for long-term reference" and "reference base picture". Otherwise (field_pic_flag is equal to 1), the resulting long-term picture number shall be one of the set of long-term picture numbers assigned to reference fields marked as "reference base picture". G.7.4.4 Slice data semantics The semantics specified in clause 7.4.4 apply. G.7.4.4.1 Slice data in scalable extension semantics The semantics specified in clause 7.4.4 apply with the following modifications. mb_skip_run specifies the number of consecutive skipped macroblocks for which, when decoding an EP slice, mb_type shall be inferred to be P_Skip and the macroblock type is collectively referred to as a P macroblock type, or for which, when decoding an EB slice, mb_type shall be inferred to be B_Skip and the macroblock type is collectively referred to as a B macroblock type. The value of mb_skip_run shall be in the range of 0 to PicSizeInMbs - CurrMbAddr, inclusive. mb_skip_flag equal