Ericsson It has been observed that specifications of new Real-time Transport Protocol (RTP) payload formats often forget to specify registration of the format's media type in the IANA registry "RTP Payload Formats Media Types" as recommended by RFC 8088. In practice this has no real impact. One reason is that the Media Types registry is the crucial registry to register any Media Type to establish the media type used to identified the format in various signaling usage. This document resolves the situation by first updating the RTP Payload Format Media Type registry to include all the known RTP payload formats at the time of writing, then it closes this IANA Registry for any future registration. Beyond instructing IANA to close this registry, the instructions to authors in RFC 8088 are updated to reflect this.