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Omnidirectional video encoding and delivery are rapidly evolving fields, where choosing an efficient representation for storage and transmission of pixel data is critical. Given that there are a number of projections (pixel representations), a projection independent measure is needed to evaluate the merits of different options. We present a technique to evaluate projection quality by rendering virtual...
In this paper, we present a depth map rate control algorithm for the High Efficiency Video Coding (HEVC) Multi-View Video plus Depth (MVD) representation. The proposed algorithm is based on a bit allocation refinement technique for key frames together with a depth-map inspired R-λ model coupled with an adaptive clipping algorithm designed to exploit the depth map characteristics. This results in improved...
The paper uses EMD to construct a new transformation matrix to improve the original matrix coding algorithm and proposes a new video steganography algorithm:Improved Matrix Encoding (IME). The proposed algorithmretains the advantages of EMD and matrix encoding that it can greatly reduce the modifications of embed carrier to achieve a high embedding efficiency under the conditions of same embedding...
High Efficiency Video Coding (HEVC) is an ongoing standard, which is an extension of H.264/AVC which is the latest coding standard. In HEVC encoder an exhaustive search method is employed to select the best mode for each macro block which consumes more encoding time. Rate and Distortion tradeoff attained for encoding each macroblock introduces more computation complexity. Although, HEVC has better...
This paper proposes a new approach for the quality control of an Mpeg2 source. Actually the VBR coder is able to assure an average constant quality (namely less variable PSNR with respect to the CBR one) but it does not in a contribution application case, where the quality constraint plays an important role and a small variance of quality could be unacceptable. The reproduced quality is mostly relayed...
The paper reports research on original techniques for compression of chrominance data in video sequences transmitted at very low bit rates. Two chrominance components are converted into one scalar chrominance signal using vector quantization in chrominance plane. Three methods for scalar chrominance compression based on transform and predictive coding are described. The important issue is that presented...
In this study, a modification to ISO MPEG-1 and MPEG-2 digital video coding standards is proposed and preliminary results on its performance are reported. The proposed modification aims to improve the visual quality of MPEG-1 and MPEG-2 coding at medium-to-low bit-rate regimes by eliminating the blocking effect caused by the Discrete Cosine Transform. This goal is achieved without introducing a significant...
This paper deals with the mode decision in an MPEG-2 framework. An algorithm for mode decision is introduced. This algorithm is based on a rate-distortion criterion and takes into account the temporal dependency of the frames. This approach can allow a quality gain of more than one dB compared to the Test Model 5 (TM5) mode decision algorithm.
Video communication at very low bit-rates has made significant progress recently through the new ITU-T standard H.263. In this paper, we are reviewing the performance advances over the 1990 ITU-T standard H.261, and present a novel extension that allows robust transmission of moving video over highly unreliable channels, such as the mobile channel.
This paper presents an analysis of a rate adaptive multimedia streaming technique according to which rate changes are obtained by varying the inter-packet transmission interval, rather than altering the source coding rate. Instead of constraining the transmitter to operate in real-time, the time scale of the proposed packet scheduler can vary between zero when the network is congested, to as faster...
This paper proposes a global rate control scheme to maximize the overall encoding quality of a network-based video composition system. The input video sources are encoded using HEVC. The rate-distortion function for each input video source is modelled based on the known PSNR and bitrates at two quantization points and the R-λ model in HEVC. By solving an R-D optimization problem, the proposed scheme...
The new video coding standard, High Efficiency Video Coding (HEVC), was developed to replace H264/AVC and 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, a conceptual HEVC encoder architecture with cascaded...
High efficiency video coding (HEVC) is a video compression standard that outperforms the predecessor H.264/AVC by doubling the compression efficiency. To enhance the coding accuracy, HEVC adopts sample adaptive offset (SAO) which classifies reconstructed pixels into different categories. During the pixel classification, however, SAO cannot use the raw samples in the current code-tree-block (CTB) boundary...
This paper presents a software implementation of context adaptive variable length decoder (CAVLD) and context adaptive variable length coder (CAVLC). Efficient algorithms for coding and decoding of Coeff_Token, levels, total zeros, and run_before have been developed, which are the five vital syntax elements of CAVLC and CAVLD. The necessary blocks namely Integer Transform, quantization and their inverses...
The main purpose of the paper is to perform a quantitative and qualitative performance evaluation of the emerging standard H.265/HEVC in comparison to its predecessor H.264/AVC. The paper focuses on both the encoding and compression efficiency by measuring the PSNR values, SSIM scores and bit rate values of reference and non-reference signals. For the needs of the paper, the HEVC and AVC reference...
This paper presents results and analysis of a compression performance test carried out within standardization activities for the HEVC standard (ITU-T H.265 and ISO/IEC 23008-2) with the focus on UHD video content. The analysis is based on subjective tests, and the performance of the new standard is compared with its predecessor AVC (ITU-T H.264 and ISO/IEC 14496-2). The Degradation Category Rating...
HEVC (High Efficiency Video Coding) standard is ready to be launched for consumer electronics. With better coding efficiency, the coding complexity is high. We propose a fast CU (Coding Unit) depth decision algorithm based on SKIP mode information in the neighboring block to early terminate the CU splitting. Compared to the HEVC standard software, the proposed method can save by up to 41% of the time...
This paper deals with the most recent video coding standard H.265/HEVC. HEVC introduces new coding tools compared to older standards. Such a change has to influence the encoder complexity and will have influence on the encoding speed. In this paper, we focus on the performance of different implementations of the HEVC. The encoders are compared on the basis of final video quality and encoding speed...
Modification of the quantizer value based on a region's visual importance within a frame is a popular and widely-used procedure in perceptual video coding. The first contribution of this paper is an alternative modification scheme. Second, our previous work, where we use saliency maps in order to guide the macroblock (MB) mode decision during the ratedistortion optimization process, is extended. Modification...
High Efficiency Video Coding (HEVC) is the most recent video compression standard that achieves higher encoding efficiency over earlier popular standards like MPEG-2 and H.264/AVC. By adopting a variety of coding efficiency enhancement and parallel processing tools, HEVC is in a position to provide up to 50% more bit-rate reduction over its precursor H.264/AVC. In an HEVC encoder, transforms are applied...
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