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Proceedings Paper

A Fixed Quality, Variable Rate Finite State Vector Quantizer For Encoding Video Over Packet Networks
Author(s): Hsiao-hui Shen; Richard L. Baker
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Paper Abstract

The advent of packet-switched networks has renewed interest in variable rate video coding schemes which can deliver a specified level of image quality. This paper describes one such scheme, using a variable rate Finite State Vector Quantizer (FSVQ). The codec alternates between an intraframe mode, for encoding foreground (moving) areas, and an interframe mode, for background areas. Separate FSVQs are used for the two modes, each with its own set of super-codebooks. Background blocks having low residual energies are conditionally replenished. The codec maintains a fixed SNR by using sub-codebooks having various numbers of codevectors and dimensions, making it an adaptive multi-rate FSVQ. Image quality is controlled by a set of SNR status variables which dynamically select classes of sub-codebooks. Each status variable is a temporally filtered measure of the SNR in a pre-assigned region of the frame that is updated each frame time. The codec may also be configured to include a rate buffer so that image quality can be degraded in a controlled fashion, should the attached network become congested. Distortion during non-congested operation is maintained to within about 1 dB of the desired value over a range of SNRs up to about 45 dB, with rates as high as 1.5 bpp.

Paper Details

Date Published: 25 October 1988
PDF: 11 pages
Proc. SPIE 1001, Visual Communications and Image Processing '88: Third in a Series, (25 October 1988); doi: 10.1117/12.968980
Show Author Affiliations
Hsiao-hui Shen, University of California Los Angeles (United States)
Richard L. Baker, University of California Los Angeles (United States)

Published in SPIE Proceedings Vol. 1001:
Visual Communications and Image Processing '88: Third in a Series
T. Russell Hsing, Editor(s)

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