Abstract
Scalable video coding is being expected in video transmission applications due to adapting for wide variety of capabilities on video terminals and network conditions. SNR scalability, where video quality is adjusted without changing the number of coded pixels, is a suitable method for such scenarios and several types of techniques have been proposed. Especially the layered coding technique has been studied in which after coded original image as the base layer, the differential image between the decoded image of base layer and original image is coded as the enhancement layer. Recently FGS (Fine Granular Scalable) technique is high profile, since it makes finer rate scalability possible because quantization is multistage and the differential image can be decoded from a part of enhancement layer bitstream. In MPEG-4 FGS, quantization is processed in DCT domain, therefore subjective quality is not always improved since quantization noise (e.g. blocking noise) occurs on the enhancement layer. This paper proposes PDS (Pixel Domain Scalable) video coding technique, in which subjective quality is possible to be adjusted more directly. For the fundamental study, this paper proposes the multistage scalar quantization PDS, and also discusses the effectiveness with the preliminary results of subjective tests.
