Obtaining image coding quantization offsets based on images and temporal layers

摘要

A method of video encoding, for video divided into image groups comprising plural temporal layers, comprises: obtaining a set of quantization offsets to be applied to an image group, a different quantization offset being obtained for at least two images belonging to the same temporal layer; and determining a quantization parameter (QP) for image encoding based on the obtained quantization set. Alternatively, a related method is also disclosed wherein a same quantization offset is obtained for at least two images belonging to different temporal layers. Thus, the quantization offset is determined not only based on the level of the temporal layer an image belongs to but also based on the quality of the reference image used for predictive encoding. Offsets may be related to the number of images using an image as a reference image for temporal prediction, the temporal distance of an image to its reference image having the lowest quantization offset, or the value of a quantization parameter applied to the reference image. Accordingly, a better rate distortion (RD) performance in a scalable video coding (SVC) scheme is obtained.