Research On Error Concealment Technology On H.264/AVC SVC

As a Scalable Video Coding (SVC) extension of the H.264/AVC standard, H.264/AVC SVC incorporates efficiently the function of scalability of temporal,spatial and quality as well as the good encoding performance. It supports transmitting and decoding partial bit streams to meet the constraint of different applications and transport environment. However, such compressed video is very sensitive to data loss in error-prone channels (e.g., IP or wireless communication networks). Channel errors can not only damage current frame, but also propagate to subsequent frames, which can significantly degrade the image quality. Error concealment (EC), which doesn't impose any additional complexity on video encoder, provides a feasible solution for error handling by recovering the damaged areas, using space and time redundant information of image and characteristics of human visual system. Therefore, it is a promising technique in theory and practice to design error concealment methods based on H.264/AVC SVC.In this paper, firstly, we briefly outline the main techniques in the order of coding framework, temporal, spatial and quality scalability in H.264/AVC SVC, and give an in-depth analysis of inter-layer prediction techniques and drift controlling techniques. Secondly, we describe spatial, frequency and temporal EC methods in turn, and introduce the five error EC algorithms in JSVM. Then an adaptive block-based EC scheme is presented to tackle the slice lose problem in spatial enhancement. Finally, on the base of introducing streaming media protocols and LiveMedia project, we design and implement a real-time streaming media transmission system.The major innovations finished are as follow:1. Based on the deep analysis of the EC module of JSVM, slice support is implemented into it to check and conceal the lost slice. Then we present a new EC scheme to tackle the slice lose problem in spatial enhancement layer based on H.264/AVC SVC. In the proposed scheme, the lost macroblock is concealed by base layer skip (BLSkip) method, or by temporal error concealment in enhancement layer (ELTEC) using external boundary matching algorithm (EBMA). Utilizing base layer MB mode, local motion similarity degree (LMSD) and blocking artifact information, the aforementioned two methods are switched adaptively. Simulation results show that the proposed methods improves the subjective video quality and obtains an average PSNR gain of about 0.21dB in low-delay application and 0.36dB in high-delay application, compared with BLSkip+FC in JSVM in the condition of equal packet loss rate.2. Based on the research on the transmission mechanism of real-time streaming media, LiveMedia library is enhanced to support H.264/AVC video stream. According to the scalability of SVC, we propose a new system solution, which provides the function of transmitting bit-stream from base layer and enhancement layer independently. Experimental results indicate that the proposed solution can not only transmit H.264/AVC video stream reliably, but also transmit SVC video stream efficiently.