Abstract: In this paper, an image sequence coding scheme for very low bit-rate video coding is presented. We examine the performance of various codebooks to remove the spatial redundancy within the difference frame. When the codec is configured to operate at 10.1 kbit/s, average PSNR values in excess of 32.86dB and 25.6dB are achieved for the 'Miss America' and 'Carphone' sequences respectively. We also present a new methodology for adaptive vector quantization (AVQ), where the codebook is updated with new vectors. The new vectors replace less significant ones in the codebook based on a novel scoring criterion that utilizes a forgetting factor and codebook half- life. The proposed method gives rise to an additional performance enhancement of around 1 dB over conventional techniques of AVQ. Furthermore, the methods do not suffer from blocking effects due to the inherent properties of both the temporal and spatial coding. !10
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