vating buffering period SEI message, it is activated. This subset sequence parameter set RBSP is called the active MVC sequence parameter set RBSP until it is deactivated when another MVC sequence parameter set RBSP becomes the active MVC sequence parameter set RBSP. A subset sequence parameter set RBSP, with that particular value of seq_parameter_set_id, shall be available to the decoding process prior to its activation. When a subset sequence parameter set RBSP (nal_unit_type is equal to 15) with a particular value of seq_parameter_set_id is not already the active MVC sequence parameter set RBSP and it is referred to by an activating buffering period SEI message (using that value of seq_parameter_set_id) that is included in an MVC scalable nesting SEI message, it is activated. This subset sequence parameter set RBSP is called the active MVC sequence parameter set RBSP until it is deactivated when another MVC sequence parameter set RBSP becomes the active MVC sequence parameter set RBSP. A subset sequence parameter set RBSP, with that particular value of seq_parameter_set_id, shall be available to the decoding process prior to its activation. NOTE 3 - The active MVC sequence parameter set RBSP is either a sequence parameter set RBSP or a subset sequence parameter set RBSP. Sequence parameter set RBSPs are activated by coded slice NAL units with nal_unit_type equal to 1 or 5 or buffering period SEI messages that are not included in an MVC scalable nesting SEI message. Subset sequence parameter sets are activated by coded slice MVC extension NAL units (nal_unit_type equal to 20) or buffering period SEI messages that are included in an MVC scalable nesting SEI message. A sequence parameter set RBSP and a subset sequence parameter set RBSP may have the same value of seq_parameter_set_id. For the following specification, the activating view buffering period SEI message for a particular value of VOIdx is specified as follows: If the access unit contains one or more than one buffering period SEI message included in an 