Bandwidth compression of digital colour-television signals using block-adaptive d.p.c.m.

This paper describes an adaptive algorithm which is capable of composite coding of broadcast-quality colour-television signals at a low bit rate. The technique involves block-adaptive predictors and block-adaptive variable-length and fixed-length quantisers. The adaptation algorithm has been extended to work at any desirable sampling frequency. As a result the low bit rate is obtained by a reduction of signal redundancy with regards to the statistical variation of each block of incoming samples. A bit-rate of only 28.34 Mb/s is obtained for a Pal colour-bar signal yielding a 50dB s.n.r. at a sampling frequency of twice the subcarrier frequency (sub-Nyquist).