Hybrid 3D subband-predictive VQ coder for VLBR applications

A dual-mode 3D based subband video coder operating at very low bit rates for PSTN and mobile networks, is proposed. When operating in baseline mode, the input video sequence is coded using a hybrid SIM3 algorithm. In 3D mode, the encoder performed subband temporal-spatial analysis using a short length QMF filter on the motion compensated frame difference frames and the resulting subbands are vector quantized using different constrained techniques. Histogram studies and modelling are also performed on the subbands and codebooks are designed according to known source distribution. Simulation results are presented at 19.2 kbit/s at 5 frame/s on QCIF format videoconferencing and videotelephony type of sequences. Subjective evaluation revealed that the annoying `blocking´ artifacts are not visible when operating in 3D mode. In addition, due to its dual-mode capability, it also performed better than SIM3 both objectively and subjectively during period of aggressive scene changes