# Video Error-Resilience Research Based on Error-Resilient Screen Content
## 1 Introduction  
With the rapid development of multimedia technology, video resolution has been constantly improving. The storage and transmission of high-definition and ultra-high-definition video bring great challenges to video coding technology. Under the background of emerging video applications and continuous innovation of network and computer technology, high-efficiency video coding (HEVC) has further optimized the H.264 coding standard according to the characteristics of high definition (HD) video. Compared with H.264/AVC, 50% bit-rate can be saved for HEVC in terms of high profile on the premise of the same video coding quality. Consequently, HEVC is widely accepted and applied [1]. Screen content image is generally composed of natural and computer-generated images--image [2]. The encoding method of screen content image can adapt to the content of both images at the same time. At present, this coding method is widely used in remote desktop sharing, video conference, radio and television, and other video applications [3]. In modern coding standards, time-domain prediction is used to eliminate the redundancy, and video data are highly dependent on each other. Packet loss will cause serious distortion after subsequent decoding. Fault-tolerant coding algorithms can reduce the errors in the process of video transmission [4]. In order to make better use of the characteristics of screen content video and improve the encoding efficiency of screen content video, VCEG and MPEG jointly issued a proposal solicitation announcement of screen content video encoding in January 2014, and officially started the work of formulating HEVC-SCC standard [5]. After a two-year proposal collection, experimental verification, performance evaluation, and other work, the videocoding standard for screen content was developed and completed in February 2016 [6]. Nevertheless, the distortion will still appear in a loss of packets for HEVC-SCC due to the bad network transmission environment, which will undermine the quality of video and affect the user experience. Therefore, the video fault tolerance mechanism is discussed to improve video quality based on HEVC-SCC in this paper. In the literature, various error-resilient mechanisms are discussed. [PERSON] et al. [7] have proposed a two-stage method to improve the error robustness of HEVC by reducing the time error propagation in the case of frame loss. In the coding stage, the number of prediction units that depend on a single reference is reduced to distribute the use of reference pictures; in the streaming stage, the MV prediction mismatch at the decoder is reduced by the priority sorting algorithm of motion vectors. In another scheme [8], frame loss simulation and corresponding error concealment are proposed to find the most effective method where the decoder is used to recover lost frames. [PERSON] et al. [9] have proposed a redundant coding method with macroblock rate and potential distortion information. The proposed algorithm is based on the given redundancy rate constraint and can achieve error resistant wireless video transmission without relying on retransmission. [PERSON] [10] put forward a method of macroblock classification based on texture characteristics, motion characteristics, and other information, and then redundantly encoded important macroblocks. A joint rate-distortion optimization algorithm for primary and redundant images is proposed and this method [11] traverses all coding modes and coding parameter combinations of redundant macroblocks and selects the best combination of rate-distortion as the final coding mode. In [12], two macroblock coding modes are added to enhance the transmission robustness of the coded bit stream. [PERSON] [13] utilized the main frame and redundant frame to generate different descriptions of MDC and analyzed the relationship between redundant frame and quantization coefficient of main frame.