Subband coding of video with adaptive vector quantization

A low bit rate adaptive video coding technique is proposed. The redundancy within adjacent video frames is exploited by motion-compensated interframe prediction, and the motion-compensated frame difference (MCFD) signal is decomposed by using a quadrature mirror filter (QMF) structure. The subband signals are vector quantized adaptively. The MCFD signals are low correlated, hence transform coding techniques are not very suitable for this kind of signal source. At 0.25-0.3 bits/pixel range, 38-40-dB peak-to-peak signal-to-noise ratio is achieved with the proposed scheme for four monochrome test sequences used: cindy, mono, duo, and quartet. The visual quality of the encoded test sequences is good, almost indistinguishable from the originals. The proposed technique outperforms the adaptive transform coding and adaptive vector quantization techniques for the tested sequences