Analysis of prediction mode decision in spatial enhancement layers in H.264/AVC SVC

Abstract

On top of the prediction modes defined in the H.264/AVC standard, Scalable Video Coding defines prediction modes for inter-layer prediction. These inter-layer prediction modes allow the re-use of coded data from the base layer, at the cost of increasing the search space at the encoder and as a result increase the encoding time. In this paper, we investigate the relation between the coding decisions taken in the base layer and the enhancement layer. Our tests have shown that a number of relations can be clearly identified. We have observed that the co-located macroblock of a base layer macroblock coded in P_8×8 mode has a 40% chance of being coded in P_8×8 mode as well. Further, we have observed that the PSkip mode is only used when the quantization parameter in the enhancement layer is high. For macroblocks coded in B_Skip mode, the co-located macroblock in the enhancement layer will be coded in the B_Skip mode when it is highly quantized (probability of 63 % to 92 % for quantization parameter 30). These observations can be used to construct a model for fast mode decision in SVC. © Springer-Verlag Berlin Heidelberg 2007.