DPCM predictive quantisation of picture signals - alters quantisation of differences to be transmitted in preset sequence

摘要

The system for the predictive quantisation of picture signals by the DPCM method, permits a reduction of the bit rate and total volume of data to be fed to a transmission or storage medium so as to make optimum use of the capacity of the transmission or storage medium. The quantisation of the differences to be transmitted is changed in a pre-set sequence; this may be done within a line, from line to line, or from frame to frame. A three point prediction may be used in which as many as possible adjacent picture elements which are coded with the higher bit number are used for the prediction. In this case the number of elements quantised with the higher step number is equal to the number quantised with the lower step number.