Low-Complexity Enhancement Layer Compression for Scalable Lossless Video Coding Based on HEVC

Abstract

Lossless compression is desired, especially for professional applications like medical imaging. However, scalability may be necessary to transmit a fast preview of pictures when the channel capacity is limited. Furthermore, there may be the need for random access to single frames of a losslessly reconstructed video. We present and evaluate a lossy-to-lossless scalable video coding system in which the scalability is achieved by using a lossy base layer (BL) in conjunction with lossless compression of the reconstruction error in the enhancement layer (EL). High Efficiency Video Coding (HEVC) is employed for encoding the BL. For compression of the EL, we propose a low-complexity scheme called sample-based weighted prediction for EL coding (SELC). Furthermore, EL compression using JPEG-LS and the scalable extension of HEVC (SHVC) are evaluated. The performance of scalable coding using each of these three methods is compared with lossless single-layer (SL) coding using the intra-main RExt configuration. Experimental results show that the scalable coding with SELC achieves average bitrate savings of 7.3% compared with the lossless SL coding, while average bitrate reductions of only 6.3% and 3.9% are obtained using JPEG-LS and SHVC, respectively. Concerning runtime, the additional encoder runtimes of SELC and JPEG-LS compared with the BL coding are negligible. In contrast to that, the runtime of the SHVC EL encoder is much higher and similar to the runtime of the BL encoder.