InterDigital InterDigital This document describes RTCP messages and RTP header extensions to enable partial access and support viewport- and region-of-interest- dependent delivery of visual volumetric media such as visual volumetric video-based coding (V3C). Partial access refers to the ability to access retrieve or deliver only a subset of the media content. The RTCP messages and RTP header extensions described in this document are useful for XR services which transport coded visual volumetric content, such as point clouds.