1.5 Prerequisites/Preconditions

H26XPF specifies only the payload formats for H.261 or H.263 video streams. It requires the establishment of an RTP stream, a mechanism for obtaining H.261 or H.263 video frames for it to convert to packets, and a mechanism for rendering H.261 or H.263 video frames that are converted to packets.

H26XPF requires an upper layer to select only one of the three payload formats explicitly.