Standardization of Freeze Frame TV Codecs.

摘要

The purpose of this report is to recommend a protocol and a compression technique to be considered as the standard for freeze frame teleconferencing equipments. The recommendations in Section 4 is based on (a) an analysis of freeze frame teleconferencing equipments presently in use, (b) consideration of previous and presently on-going standardization efforts in related areas by respected technical organizations, and (c) the unique requirements teleconferencing places on freeze frame technology; ie, compression, transmission, resolution, gray scale, storage, and display. Freeze frame technology as used in this report is a technique by means of which images normally requiring a wide band communication circuit for transmission can be transmitted over narrow band circuits. This is accomplished by selecting individual frames or fields from a television signal train for transmission. The concept of motion is, of course, lost, but the information content of a frame is conveyed in its entirety (up to the specifications of the codec). The trade-off is channel bandwidth versus transmission time. (RH)