25 October 1988 A Fixed Quality, Variable Rate Finite State Vector Quantizer For Encoding Video Over Packet Networks
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Proceedings Volume 1001, Visual Communications and Image Processing '88: Third in a Series; (1988) https://doi.org/10.1117/12.968980
Event: Visual Communications and Image Processing III, 1988, Cambridge, MA, United States
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.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hsiao-hui Shen, Hsiao-hui Shen, Richard L. Baker, Richard L. Baker, } "A Fixed Quality, Variable Rate Finite State Vector Quantizer For Encoding Video Over Packet Networks", Proc. SPIE 1001, Visual Communications and Image Processing '88: Third in a Series, (25 October 1988); doi: 10.1117/12.968980; https://doi.org/10.1117/12.968980
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