H.320 Overview Multimedia Teleconferencing Standards The ITU-T T.120, H.320, H.323, and H.324 standards comprise the core technologies for multimedia teleconferencing. The T.120 standards address Real Time Data Conferencing (Audiographics), the H.320 standards address ISDN Videoconferencing, the H.323 standard addresses Video (Audiovisual) communication on Local Area Networks, and the H.324 standard addresses High Quality Video and Audio Compression over POTS modem connections. Each of these standards has been developed in accordance with the process described above. The IMTC expects to continue to contribute, through its members, to the future enhancement of the standards to incorporate new functionality and capabilities. H.320 Overview The H.320-series governs the basic video-telephony concepts of audio, video and graphical communications by specifying requirements for processing audio and video information, providing common formats for compatible audio/video inputs and outputs, and protocols that allow a multimedia terminal to utilize the communications links and synchronization of audio and video signals. Like the other multimedia teleconferencing standards, H.320 applies to multipoint and point-to-point sessions. The H.320 suite addresses videoconferencing over circuit switched services like ISDN or Switched-56. The components of the H.320 standard are summarized in Table 1. Table 1: Multimedia Teleconferencing Standards Recommendations in Force H.320 - Narrow-band Visual Telephone Systems and Terminal Equipment H.221 - Frame Structure for a 64 to 1920 kbit/s Channel in Audiovisual Teleservices H.261 - Video Codecs For Audiovisual Services at Px64 Kbps HTML Other Formats H.230 - Frame-synchronous Control and Indication Signals for Audiovisual Systems H.231 - Multipoint Control Unit for Audiovisual Systems Using Digital Channels up to 2 Mbit/s H.243 - System for Establishing Communication Between Three or More Audiovisual Terminals Using Digital Channels up to 2 Mbit/s G.711 - Pulse Code Modulation (PCM) of Voice Frequencies G.722 - 7 kHz Audio-coding Within 64 kbit/s G.728 - Coding of Speech at 16 kbit/s Using Low-delay Code Excited Linear Prediction Draft Recommendations PictureTel H.324 Archive - H.324, "Visual Telephone Terminals over GSTN", includes: H.263 - Video Coding For Low Bitrate Communication HTML MS-Word H.324 - Visual Telephone Terminals over GSTN H.245 - Control of Communications Between Multimedia Terminals H.223 - Multiplexing Protocols for Low Bitrate Multimedia Terminals G.723 - Dual Rate Speech Coder for Multimedia Telecommunications Transmitting at 6.4 and 5.3 kbit/s H.321 - Visual Telephone Terminals over ATM H.322 - Visual Telephone Terminals over Guaranteed Quality of Service LANs H.221 Frame structure for a 64 to 1920 Kbps channel in audiovisual teleservices. Ratified H.320 Asosiasi Penyelenggara Jasa Internet Indonesia [APJII] Indonesian Internet Service Provider Association Grha Citra Caraka [GCC], TELKOM Bldg, Mezzanine Fl. Jln Jend Gatot Subroto 52, Jakarta 12710 - INDONESIA MAIN-NOC: http://www.iix.net.id [Network Access Point - NAP] I: http://www.apjii.or.id V:+62-21 526 8777 F:+62-21 526 8789 E: [EMAIL PROTECTED] -- STOP-LANGGANAN: 'unsubscribe' ke: [EMAIL PROTECTED] START-LANGGANAN: 'subscribe' ke: [EMAIL PROTECTED]
