Low latency directional filtering for inter-layer prediction in scalable video coding using HEVC

In scalable video coding, reconstructed base-layer samples can be used as predictor for compressing enhancement-layer samples. This inter-layer predictor typically exhibits specific type of artifacts, arising from coarse quantization and upsampling processes. To suppress these artifacts, we propose an inter-layer filtering scheme which adapts to local orientations. On a sample-by-sample basis, it first determines the orientation class by comparing simple gradient measurements. According to the determined orientation, a corresponding directional filter constructed with predetermined coefficients, is selected and then applied. Our filtering scheme achieves low encoding latency and also avoids complicated normalization processes typically associated with other low-latency filtering methods. Based on complexity analysis and simulation results, we demonstrate that, compared with other inter-later filtering approaches, our method provides a viable complexity-efficiency trade-off for practical scalable video applications.