The ITU Radiocommunication Assembly considering that a large and growing number of 35 mm feature films are produced in multichannel sound; that the Dolby Surround format was launched to allow the multichannel sound accompaniment from the cinema environment to be conveyed over two-channel delivery media; that the Dolby Surround format has spread widely and today is available in many households; that a large number of broadcasters are transmitting or planning to transmit these films employing the Dolby Surround system to television viewers; that a large number of home television viewers are equipped to reproduce matrix surround encoded soundtracks in their homes; that a large majority of those television viewers use the Dolby Pro Logic surround decoder; that broadcasters may produce and deliver multichannel programmes employing the same Dolby Surround format that is used with feature films; that a larger existing base of viewers are still equipped with mono and stereo reproduction equipment, which will be receiving multichannel sound; that new multichannel sound transmissions must be compatible with existing mono and stereo equipment; that production of multichannel sound requires correct technological procedures before transmission in order to assure compatibility with monophonic, stereophonic, and surround sound reproduction.
ITU-R BS.1423 SPANISH-1999 history
1999ITU-R BS.1423 SPANISH-1999 GUIDELINES FOR PRODUCING MULTICHANNEL SOUNDTRACKS USING SURROUND MATRIX TECHNIQUES