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High Efficiency Video Coding (HEVC)is the latest video coding standard established, which introduces a number of new coding tools such as hierarchical structures of coding unit (CU), prediction unit (PU) and transform unit (TU) to improve the compression capacity of encoding. Compared with H.264/AVC, the compression performance increased by nearly 50% at the cost of the algorithm complexity increasing...
While adaptive splitting the quadtree-structured coding units according to the video content is utmost important in achieving the best encoding performance of the High Efficiency Video Coding (MPEG-H HEVC/H.265), the newest video coding standard, its optimal decision requires much computation. To resolve this complexity problem, we extend the keypoint-based CU depth decision (KCD) method by further...
High Efficiency Video Coding (HEVC), the newest video coding standard established, aims to significantly improve the compression performance compared with H.264/AVC and other existing video coding standards. In the intra coding of HEVC, this improvement is achieved by adopting the coding tree unit (CTU) structure and providing up to 35 prediction modes for each prediction unit (PU). However, the computational...
In many multimedia applications, image encryption has to be conducted prior to image compression. This paper proposes an Encryption-then-Compression system using a JPEG XR friendly perceptual encryption method, which enables to be conducted prior to JPEG XR compression. The proposed encryption method can provide approximately the same compression performance as that of JPEG XR compression without...
Motion estimation (ME) plays an essential role in video coding, but ME is also the most time-consuming part. Therefore, the algorithm for ME should be optimized for guaranteeing the real time performance of encoder. UMHexagonS algorithm, as one of the fast ME algorithms, has been accepted by AVS+. An improved UMHexagonS algorithm is proposed in this paper. In the proposed algorithm, the fixed asymmetrical...
With the explosive growth of video data, content-based video analysis and management technologies such as indexing, browsing and retrieval have drawn much attention. Video shot boundary detection (SBD) is usually the first and important step for those technologies. Great efforts have been made to improve the accuracy of SBD algorithms. However, most works are based on signal rather than interpretable...
Broadcast providers are looking for new opportunities to increase user experience and user interaction on their content. Their main goal is to attract and preserve viewer attention to create a big and stable audience. This could be achieved with a second screen application that lets the users select their own viewpoint in an extremely high resolution video to direct their own first screen. By allowing...
High Efficiency Video Coding (HEVC) achieves high efficiency by introducing a new coding structure in adoption of coding unit (CU), prediction unit (PU) and transform unit (TU). However, it also imposes great computation burden on the mode decision of encoders. In this paper, we propose a fast CU depth decision scheme to reduce the encoder complexity for HEVC. Firstly, the relationship between rate-distortion...
Depth-image-based rendering (DIBR) technique is widely used to synthesize virtual views in many applications including multiview and free viewpoint video systems. An inherent problem of DIBR oriented view synthesis is that holes may appear in the synthesized view. Hole filling techniques generally extrapolates/interpolates the hole regions with the neighboring information based on an assumption that...
Cloud-based video monitoring system has many advantages and interesting applications. However, it has a critical problem of invading privacy. For example, if cloud servers or transmission channels are attacked, their private data can be leaked to the attackers. If we use well-known encryption schemes such as AES or DES, the security lifetime will increase but it requires additional computational operations...
In distributed video coding (DVC), channel coding technique plays a key role to improve the coding performance. However, many iterative channel coding schemes such as LDPC codes and turbo codes suffer from error floor region, which can give some negative impact to the DVC such as degradation in rate-distortion performance. In this paper, to reduce this error floor problem in rate adaptive LDPC code,...
Due to the shared nature of IP networks, the available network bandwidth is not constant and varies during transmission. In order to have better quality, efficient bandwidth utilization and network congestion management, the outgoing bitrate of a streaming application should adapt to changes in network traffic as fast as possible. The adaption time is very critical and plays an important role in the...
Gartner predicts that by 2013 mobile devices will overtake PCs as the most popular type of device used for accessing Internet-based services. Meanwhile, mobile phones are becoming increasingly complex and powerful. However, battery technology has not been increasing at the same pace and hence, there is an urgent need for solutions to balance the battery performance of mobile devices and their functionality...
In this paper, we propose to compare two different H.264/AVC intra transrating architectures based on frequency position selectivity and frequency level selectivity respectively, using intra high-definition video bitstreams. We evaluate these solutions in terms of bitrate reduction and visual quality using both PSNR and Video Quality Metric (VQM) experiments. Simulation results show that the frequency...
Motion estimation and compensation is an essential part of several video coding standards. Moreover motion information takes significant part of compressed bit stream, especially in low bit rate situation. This paper proposes an efficient technique which merges motion-based competitive spatio-temporal technique and multi-frames references scheme for efficient motion information prediction. Simulation...
Adaptive arithmetic coding is a general technique for coding the symbols of a stochastic process based on an adaptive model. The adaptive model provides the code symbol statistics and is updated along with encoding/decoding processes when more encoded/decoded symbols are fed as samples to the adaptive model. The coding performance depends on how well the adaptive model fits the symbol statistics....
Distributed video coding allows the compression of video frames in a distributed fashion leading to a rather simple computational encoding, but requiring a complex decoding. The main drawback however is the decoding complexity making some practical applications difficult. Nowadays, most distributed video coding schemes are based on efficient channel codes such as LDPC and Turbo codes. This is the...
In traditional video broadcast systems, the encoders have to insert periodical I frames (a.k.a. key frame) in order to allow newly arrived receivers to be able to start the decoding process in a timely manner. However, such insertion of periodical I frames will result a loss of encoding efficiency as these frames could actually have been encoded into more bit-rate efficient P/B frames instead. This...
In this work, we aim to develop a fast block mode decision in the multiview video coding (MVC) for the non-anchor pictures, especially with motion skip (MS) mode enabled to further exploit the inter-view correlations for higher coding efficiency. To combat with the complexity increase with the additional adopted MS mode, one primary contribution of this work is to speed up the MS mode decision by...
In a digital television scenario, the video signal may have different bit rates, encoding formats, and spatial resolutions according to the type of transmission, the application, and the receiver. To flexibly deliver video to users with different available resources, the content needs to be adapted dynamically. Video transcoding is the operation of converting a video from one format into another....
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