Robust 3-dimensional subband video coder based on dithered pyramid vector quantizer

We present our results on the development of a robust video coder. The system consists of 3-dimensional subband filtering, optimized scalar quantization of the lowest temporal-spatial frequency subband and modified pyramid vector quantization for high frequency subbands. To improve the visual quality of the system at low bit-rates, dithering is used for the pyramid vector quantizers and its effectiveness is proved by a pair-comparison subjective test. To increase robustness to noise, productive enumeration is used for the pyramid vector quantizers. Also, with phase scrambling, the distribution of the lowest temporal-spatial band is changed to Gaussian which results in a better scalar quantization coding gain for this band and, by using a folded binary code, less sensitivity to noise. Results shows that at a high bit-error rate (5/spl times/10/sup -3/), the coder in average loses only 4 dB in peak signal-to-noise ratio.