ixels), 4CIF (704x576 pixels) and 16CIF (1408x1152 pixels). H.310 H.310 is an ITU-T draft standard for broadcast (HDTV) quality video conferencing. It describes how MPEG-2 video can be transmitted over high-speed ATM networks. The standard includes subparts such Glossary of Terms as H.262 (MPEG-2 video standard), H.222.0 (MPEG-2 Program and Transport Stream), H.222.1 (MPEG-2 streams over ATM) and a variety of G.7XX audio compression standards. H.310 takes H.320 to the next generation of networks (broadband ISDN and ATM). H.320 An ITU-T standard formally known as "Narrow-band Visual Telephone Systems and Terminal Equipment." H.320 includes a number of individual recommendations for coding, framing, signaling and establishing connections (H.221, H.230, H.321, H.242, and H.261). It applies to point-to-point and multipoint videoconferencing sessions and includes three audio algorithms, G.721, G.722 and G.728. H.321 H.321 adapts H.320 to next-generation topologies such as ATM and broadband ISDN. It retains H.320's overall structure and some of its components, including H.261 and adds enhancements to adapt it to cell-switched networks. H.322 H.322 is an enhanced version of H.320 optimized for networks that guarantee Quality of Service (QoS) for isochronous traffic such as real-time video. It will be first used with IEEE 802.9a isochronous Ethernet LANs. H.323 H.323 extends H.320 to Ethernet, Token-Ring, and other packet-switched networks that do not guarantee QoS. It will support both point-to-point and multipoint operations. QoS issues will be addressed by a centralized gatekeeper component that lets LAN administrators manage video traffic on the backbone. Another integral part of the spec defines a LAN/H.320 gateway that will allow any H.323 node to interoperate with H.320 products. In addition to H.320's H.261 video codec H.323 also H.263, a more sophisticated video codec. Also in the family are H.225 (specifies call control messages); H.245 (specifies messages for opening and controlling channels for media streams)