Coded Block Pattern Research Articles

Fast Mode Decision Using Inter-View and Inter-Component Correlations for Multiview Depth Video Coding

With the development of three-dimensional (3-D) display technologies, 3-D video has attracted more and more interest. Multiview video plus depth (MVD) is one of the most popular representation formats of 3-D video. In MVD coding system, multiview depth video needs to be coded and transmitted in addition to the texture video. This paper presents a novel fast mode decision (FMD) method for odd views in multiview depth video coding. First, the inter-view and inter-component coding correlations are analyzed to provide efficient reference information. Then, with a view to the characteristics of different types of frames, different early termination strategies are proposed. For the nonanchor frame, the early termination criterion is based on the rate-distortion cost information of the even views and the coded block pattern information. For the anchor frame, the criterion is set stricter to maintain the coding accuracy. Experimental results show that the proposed method can reduce 78.07% coding time on average, without significant loss of video quality.

Efficient Motion and Disparity Estimation Optimization for Low Complexity Multiview Video Coding

The use of variable block-size motion estimation (ME), disparity estimation (DE), and multiple reference frames selection aims to improve the coding efficiency of multiview video coding (MVC), however, this is at the cost of high computational complexity of these advanced coding techniques, which are not suitable for real-time video broadcasting applications. In this paper, we propose an efficient ME and DE algorithm for reducing the computational complexity of MVC. Firstly, according to the characteristics of the coded block pattern and rate distortion (RD) cost, an early DIRECT mode decision algorithm is proposed. Then, based on the characteristics of the initial search point in the ME/DE process and the observation that the best point is center-biased, an early ME/DE termination strategy is proposed. If the ME/DE early termination is not satisfied, the ME/DE search window will be reduced by applying the optimal theory. At last, two block matching search strategies are proposed to predict the best point for the ME/DE. Experimental results show that the proposed algorithm can achieve 50.05% to 77.61%, 64.83% on average encoding time saving. Meanwhile, the RD performance degradation is negligible. Especially, the proposed algorithm can be applied to not only the odd views but also the even views.

General Architecture for MPEG-2/H.263/H.264 to H.264 Inter P Frame Video Transcoding

The latest international video coding standard H.264/AVC significantly achieves better coding performance compared to prior video coding standards such as MPEG-2 and H.263, which have been widely used in today’s digital video applications. To provide the interoperability between different coding standards, this paper proposes an efficient and general architecture for MPEG-2/H.263/H.264/AVC to H.264/AVC inter P frame transcoding, using the original information such as coded mode type (CMT), coded block pattern (CBP) and motion vector (MV). The experimental results conducted on H.264/AVC reference software JM12.2 reveal that average 93 % of computation (re-encoding) time can be saved (corresponding to a speed-up factor of 16), while still preserving good coding performance when compared with complex cascaded pixel domain transcoding (CCPDT). The results also indicate that the proposed algorithm significantly outperforms other distinct algorithms, in both rate-distortion performance and computation performance.

DIRECT Mode Early Decision Optimization Based on Rate Distortion Cost Property and Inter-view Correlation

In this paper, an Efficient DIRECT Mode Early Decision (EDMED) algorithm is proposed for low complexity multiview video coding. Two phases are included in the proposed EDMED: 1) early decision of DIRECT mode is made before doing time-consuming motion estimation/disparity estimation, where adaptive rate-distortion (RD) cost threshold, inter-view DIRECT mode correlation and coded block pattern are jointly utilized; and 2) false rejected DIRECT mode macroblocks of the first phase are then successfully terminated based on weighted RD cost comparison between 16 16 and DIRECT modes for further complexity reduction. Experimental results show that the proposed EDMED algorithm achieves 11.76% more complexity reduction than that achieved by the state-of-the-art SDMET for the temporal views. Also, it achieves a reduction of 50.98% to 81.13% (69.15% on average) in encoding time for inter-view, which is 29.31% and 15.03% more than the encoding time reduction achieved by the state-of-the-art schemes. Meanwhile, the average Peak Signal-to-Noise Ratio (PSNR) degrades 0.05 dB and average bit rate increases by , which is negligible.

Fast mode decision based on texture–depth correlation and motion prediction for multiview depth video coding

The motion estimation and disparity estimation are used to remove the temporal and inter-view redundancies in multiview plus depth video coding, however, the variable block-size ME and DE make the computational complexity increase dramatically. This drawback limits it to be applied in real-time applications. In this paper, based on the mode correlations between depth video and its corresponding texture video, motion prediction and coded block pattern, we propose a fast mode decision algorithm to reduce the computational complexity of multiview depth video coding. Experimental results show that the proposed algorithm can achieve 67.18 and 69.90 % encoding time saving for even and odd views, respectively, while maintaining a comparable rate-distortion performance. In addition, with the dramatic encoding time reduction, the proposed algorithm becomes more suitable for real-time applications.

Fast mode decision algorithm for scalable video coding based on luminance coded block pattern

A fast mode decision algorithm is proposed to reduce the com- putation complexity of adaptive inter layer prediction method, which is a motion estimation algorithm for video compression in scalable video cod- ing (SVC) encoder systems. SVC is standard as an extension of H.264/ AVC to provide multimedia services within variable transport environments and across various terminal systems. SVC supports an adaptive inter mode prediction, which includes not only the temporal prediction modes with varying block sizes but also inter layer prediction modes based on correlation between the lower layer information and the current layer. To achieve high coding efficiency, a rate distortion optimization technique is employed to select the best coding mode and reference frame for each MB. As a result, the performance gains of SVC come with increased com- putational complexity. To overcome this problem, we propose fast mode decision based on coded block pattern (CBP) of 16 × 16 mode and refer- ence block of best CBP. The experimental results in SVC with combined scalability structure show that the proposed algorithm achieves up to an average 61.65% speed up factor in the encoding time with a negligible bit increment and a minimal image quality loss. In addition, experimental results in spatial and quality scalability show that the computational com- plexity has been reduced about 55.32% and 52.69%, respectively. © 2013

A novel early SKIP mode detection method for coarse grain quality in H.264/SVC

Various fast mode decision algorithms are proposed to reduce computational complexity for the H.264/scalable video coding standard. In this article, we focus on skip mode detection for coarse grain quality (CGS). We propose a fast skip mode detection approach by exploiting surrounding skip patterns, rate distortion (RD) cost and coded block pattern (CBP). Experimental results show that, with 0.589% BDBR and 0.011 dB BDPSNR loss on average, the proposed method achieves considerable encoding time reduction compared with the reference software. Compared with the state-of-the-art early skip algorithm, the proposed method also achieves 9.98% time reduction on average.

Mode decision acceleration for scalable video coding through coded block pattern

This paper presents a fast mode decision to accelerate the encoding process of scalable video coding (SVC) through coded block pattern (CBP) analysis. CBP contains residual information of each macroblock (MB) and provide cues for mode prediction in encoding process. The proposed algorithm makes use of the existing mode information in base layer (BL), enhancement layer (EL) and CBP to remove invalid modes for the mode prediction of the current MB in EL coding. Also, the EL’s modes in the highest temporal level of a group of picture are determined by high correlation exists in adjacent frames. Experimental results show that the proposed algorithm saves an average of 68% of EL motion estimation time with minor degradation in PSNR and with few bitrate increase of SVC quality and spatial scalabilities when compared to JSVM 9.19.14. Our algorithm outperforms the best-known method by 17% EL motion estimation time saving in average.

Context-adaptive coded block pattern coding for H.264/AVC

For coding of quantized transform coefficients, a coded block pattern (CBP) is a key syntax element to represent the existence of coefficients in a macroblock efficiently. In H.264/AVC, the CBP is coded by using a fixed variable length coding table, called Exp-Golomb codes. However, since the CBP is highly affected by the change of quantization parameter (QP), in this paper, we show the CBP distributions according to the change of QP and propose an context-adaptive CBP coding method. The proposed scheme selects the coding table adaptively based on the context of neighbors' CBP. Experimental results show that the proposed scheme reduces average 1.15% in total bit rate and 12.54% in CBP bit rate compared to the anchor, H.264/AVC.

스케일러블 비디오 부호화를 위한 효율적인 엔트로피 부호화 방법

Generally existing video codec employs entropy coding to deal with residual signals with considering temporal and spatial properties. Scalable Video Coding(SVC) which is extension of H.264/AVC has three technical concepts for removing redundancies between inter-layers. In spite of using novel prediction method between inter-layers in SVC, it is still using same entropy coding method to residual signals. According to the studies, the residual obtained by inter-layer prediction technique has different features of residual signal acquired by spatial or temporal prediction technique. In this paper, we propose an efficient entropy coding method which codes the residual signal obtained by inter-layer prediction with regarding its features adequately. We re-designed the Coded Block Pattern(CBP) table suitably for inter-layer texture prediction. The experiments show that the proposed method can further reduce the BD-Bitrate up to average 2.20% in 4CIF and 1.14% in CIF resolution compared to the existing JSVM 9.18.

가변 블록 부호화에서 CBP를 이용한 고속 인터모드 결정 방법

In this paper, we propose the method that reduce computational complexity for intermode decision using CBP(coded block pattern) and coded information of colocated-MB(macro block). Proposed method classifies MB into best-CBP and normal-CBP according to the characteristics of CBP. On best-CBP, it eliminates the computation for mode on intermode decision process because the probability for SKIP mode and M-Type mode is 96.3% statistically. On normal-CBP, it selectively eliminates the amount of computation for bit-rate distortion cost, because it uses coded information of colocated-MB and motion vector cost in deciding SKIP mode and M-Type mode. The simulation results show that the proposed method reduces total coding time to 58.44% in average, and is effective in reducing computational burden in videos with little motion.

Perceptual video encryption scheme for mobile application based on H.264

Security video communication is a challenging task, especially for wireless video applications. A perceptual video encryption scheme is proposed based on exploiting the special feature of entropy coding in H.264. The encryption scheme is compose of coded block pattern permutation, sign of trailing ones scrambling and levels of nonzero coefficients encryption. The important syntax elements and sensitive coded elements are chosen to encrypt using mathematical operations, permutation and stream ciphers. Experimental results show that the proposed perceptual scheme can achieve high security at a relatively low compression ratio and bandwidth cost, as well as rather low complexity and time cost, so it is suitable for security multimedia services for mobile device and wireless application.

A first approach to speeding-up the inter mode selection in MPEG-2/H.264 transcoders using machine learning

The H.264 standard achieves much higher coding efficiency than the MPEG-2 standard, due to its improved inter and intra prediction modes which come with a cost of higher computation complexity. Transcoding MPEG-2 video to H.264 is important to enable gradual migration to H.264. However, given the significant differences between the MPEG-2 and the H.264 coding algorithms, transcoding is much more complex and new approaches to transcoding are necessary. In this paper, we introduce and evaluate a low complexity macroblock partition mode decision algorithm, to be used as part of a high-efficient inter-frame prediction in MPEG-2 to H.264 transcoder. The proposed tools are used to compute an optimal MB coding mode decision with significantly reduced computational complexity. Specifically, we achieve the computational savings by using the following MB information coming from MPEG-2: the MB coding modes, the coded block pattern (CBPC) in MPEG-2, and the mean and variance of the 16 4?×?4 sub blocks of the MPEG-2 residual MBs. We use data mining algorithms to develop a decision tree for H.264 coding mode decisions. The decision trees are built using RD optimized mode decisions and result in highly efficient mode decisions, with significantly reduced computational complexity. The proposed transcoder is 35% faster than the RD optimized H.264 reference transcoder without a significant PSNR degradation (0.05 dB on average). The proposed transcoder performs over 0.4 dB better on average than the SAE cost based H.264 transcoding.

An Error Detection Method Based on Coded Block Pattern Information Verification for Wireless Video Communication

A novel error detection method based on coded block pattern (CBP) information verification is proposed for error concealment of inter-coded video frames transmitted in wireless channel. This method firstly modifies the original video stream structure by the aggregation of certain important information, and then inserts some error verification bits into the video stream for each encoded macro block (MB), these bits can be used as reference information to determine whether each encoded MB is corrupted. Experimental results on additive Gauss white noise simulation wireless channel and H.263+ baseline codec show that the proposed method can outperform other reference approaches on error detection performance. In addition, it can preserve the original video quality with a small coding overhead increase.

Symbol re-mapping methodfor improvement of TML-1 VLC coder

To improve the efficiency of variable length codeword (VLC) encoding in TML-1 for H.26L, the authors propose to adaptively change the mapping relationship between a symbol and its bit pattern in the VLC table, based on a local measurement of the symbol probability. Simulation results show that the proposed method gives a ~30 and 37% reduction in the average bit rate for macro block type and coded block pattern information, respectively.