In the current VSEI working draft, the neural-network post-filter characteristics SEI message is defined on CVS and activated by the neural-network post-filter activation SEI message on PU. When there are some cases of activating all pictures in CVS, for example, in chroma format transformation, activating them for each picture is inefficient. Therefore, this contribution proposes alternative solutions. One method is to activate all pictures in the CVS, and the other is to activate pictures indicating the nuh_layer_id and the TemporalID of the NAL unit header.