Macroblock Size Research Articles

Authenticated encryption mode with blocks skipping

Block symmetric ciphers are one of the most important components of modern information security systems. At the same time, in addition to the structure of the applied block symmetric cipher, the cryptographic strength and performance of the information protection system is largely determined by the applied encryption mode. In addition to high performance and high-quality destruction of block statistics, modern encryption modes should also protect encrypted information from occurred or intentionally introduced errors. In this paper, we have developed an encryption mode with blocks skipping and using a pseudo-random key sequence generator, which allows checking the integrity of encrypted information with accurate detection of the place where an error was introduced. In this case, the error detection accuracy is determined by the adjustable parameter of the macroblock size and can be set depending on the level of importance of the protected information. The developed encryption mode is characterized by the following key advantages: reducing the number of required encryption operations by half, while providing a high level of cryptographic quality; more effective destruction of macroblock statistics due to the use of an additional generator of pseudo-random key sequences, the impossibility of propagation of the occurred (intentionally introduced) error outside the macroblock, as well as higher values of the number of protection levels due to the possibility of classifying the initial states of the applied generators of pseudo-random key sequences. As proposed in this paper, the mode of authenticated encryption with blocks skipping can be recommended for use on mobile platforms that are demanding both in terms of the quality and reliability of the protected information and are limited in terms of computing and power resources.

Block Matching Algorithm (BMA) of the Hybrid Adaptive Rood Pattern Search (ARPS) Based on Its Motion Speed

There are several numbers famous proposed Block Matching Algorithm (BMA) in video coding technique and among it, the ARPS is a well known BMA technique that produce lower computational complexity and higher quality of the encoded video at the same time. In general, a video will has a lot of temporal redundancy among its neighborhood frames especially for a low motion video which make encoding a low motion video with smaller MB and bigger p size seemed impractical and vice versa. In this paper, the hybrid version of ARPS technique is used depending on its motion video type either low, medium, or high motion video. Basically this hybrid model works by setting the Macro Block (MB) and Search Range Size, p according to the motion type. Low motion video will be use higher size of MB and smaller size of p, medium motion has medium size of MB and p, and high or fast motion video will use smaller MB and bigger p size. The experimental result shows that by using the hybrid BMA technique, it can produce a better quality of the constructed frame and also it achieve less computational complexity at the same time.

Super-resolution with selective filter based on adaptive window and variable macro-block size

Super-resolution (SR) covers a set of techniques whose objective is to improve the spatial resolution of a video sequence or a single frame. In this scope, fusion SR techniques obtain high-resolution (HR) frames taking as a reference several low-resolution (LR) frames contained in a video sequence. This paper is based on a selective filter to decide the best LR frames to be used in the super-resolution process. Additionally, each frame division into macro-blocks (MBs) is analyzed both in a fixed block size approach, which decides which MBs should be used in the process, and in a variable block size approach with an adaptive MB size, which has been developed to set an appropriate frame division into MBs with variable size. These contributions not only improve the quality of video sequences, but also reduce the computational cost of a baseline SR algorithm, avoiding the incorporation of non-correlated data. Furthermore, this paper explains the way in which the enhanced algorithm proposed in it outperforms the quality of typical SR applications, such as underwater imagery, surveillance video, or remote sensing. The results are provided in a test environment to objectively compare the image quality enhancement obtained by bilinear interpolation, by the baseline SR algorithm, and by the proposed methods, thus presenting a quantitative comparison based on peak signal-to-noise ratio (PSNR) and Structural SIMilarity (SSIM) index parameters. The comparison has also been extended to other relevant proposals of the state of the art. The proposed algorithm significantly speeds up the previous ones, allowing real-time execution under certain conditions.

An adaptive macroblock-mean difference based sorting scheme for fast normalized partial distortion search motion estimation

This work presents an efficient lossy partial distortion search (PDS) algorithm called adaptive mean difference based partial distortion search (AMDNPDS). The proposed AMDNPDS algorithm reduces computations by using a halfway-stop technique in the calculation of the macroblock (MB) distortion measure and applying a diagonal search pattern for stationary or quasi-stationary candidate MBs. For the matching point reduction, a MB is divided into 4×4 sub-MBs with each sub-MB sorted by subtracting the MB mean value. Therefore, the mean difference pixels are retrieved one at time to obtain the accumulated partial SAD used as a constraint for checking the validity of a candidate MB. The proposed scheme can accelerate the convergence speed and efficiently eliminate the impossible candidates earlier, resulting in substantial computation reduction. The experimental results show the proposed algorithm reduces the check pixels by about 11.02 times on average compared with the typical partial distortion search (PDS) when the motion MB size is 16×16 and the search range is ±15. Compared with other lossy PDS algorithm such as normalized PDS (NPDS), which achieved reductions of 1.82 times on average, reductions in computational complexity were achieved. In addition, the proposed algorithm achieved 59.78% of total motion estimation (ME) time saving compared to the NPDS algorithm and 58% total ME time in comparison to the prediction error prioritizing-based NPDS (PEPNPDS) algorithm when using H.264/AVC JM 18.2 reference software according to different types of sequences, while maintaining a similar bit-rate without losing picture quality.

A Comparison of Different Block Matching Algorithms for Motion Estimation

In this paper, four different block matching algorithms using motion estimation are evaluated where the effects of the macro block size used will be reviewed to find the best algorithm among them is scrutinized to determine the most optimal algorithm. Four different block matching algorithms are considered and implemented. Each algorithm is evaluated using different movies from the TRANS database [11] and comparisons are made through the Peak Signal to Noise Ratio (PSNR) and search points per macro block (i.e. computation time) for different sizes of macro blocks and search areas. The results suggest that among all the evaluated algorithms, ARPS has the best PSNR based on computation time.

Advanced SIMD를 이용한 화면 간 예측 고속화방법

본 논문에서는 ARM Cortex-A9 듀얼코어 플랫폼에서 지원하는 병렬처리 기법 중 하나인 Advanced SIMD기반의 NEON을 적용한 H.264/AVC 고속화 움직임추정 방법론을 연구하였다. 다양한 움직임추정 방법 중 하나인 전역탐색기법에 NEON을 적용하여 각 매크로블록의 SAD 연산횟수를 1/4 감소시켰다. 해당 매크로블록의 픽셀 값들을 8개의 16bit NEON 레지스터에 할당하였고, NEON에서 지원하는 Intrinsic 함수를 사용하여 동시에 128bit 연산을 수행하였다. 이러한 방법으로 계산된 SAD 값들 중 최소 SAD 값을 가지고 정확한 모션벡터를 선정했다. 그 결과 영상의 크기 및 매크로블록의 크기에 따라 성능이 평균 30% 이상 향상되는 효과를 검증하였다. An H.264/AVC fast motion estimation methodology is presented in this paper. Advanced SIMD based NEON which is one of the parallel processing methods is supported under the ARM Cortex-A9 dual-core platform. NEON is applied to a full search technique with one of the various motion estimation methods and SAD operation count of each macroblock is reduced to 1/4. Pixel values of the corresponding macroblock are assigned to eight 16-bit NEON registers and Intrinsic function in NEON architecture carried out 128 bits arithmetic operations at the same time. In this way, the exact motion vector with the minimum SAD value among the calculated SAD values can be designated. Experimental results show that performance gets improved 30% above average in accordance with the size of image and macroblock.

A real-time video watermarking algorithm for streaming media

Video watermarking technology is a useful method to track piracy for digital videos. However, most watermarking algorithms cannot be directly applied to H.264 streaming media because of their poor real-time performance, which may cause users to watch the video unsmoothly. In order to solve this problem, a real-time H.264 video watermarking algorithm (RVWA) is proposed. First, the video is segmented before embedding watermark, which makes watermark embedding and video transmission be carried on at the same time. Then, the concept of watermark embedding margin of frame (WEMF) is proposed to shorten the watermark embedding time. By calculating the value of WEMF for each B frame, which is related to its frame bits, suitable B-frames can be selected to embed watermark without decoding it completely. Finally, with the characteristic of variable macro block size in H.264 coding standard, a simplified formula is presented to quickly calculate the just noticeable difference (JND) value of the macro block, and then the macro blocks with larger JND value are selected to embed watermark into their motion vectors, which also provides good invisibility. Experimental results show that the proposed algorithm can find suitable embedding positions and embed watermark quickly with good invisibility and less increase of the bit-rate of video. RVWA algorithm can be used in stream media environment in real time.

Fast mode decision algorithm for extended macroblock motion estimation in key technology areas

Block sizes larger than the traditional 16×16 macroblock (MB) structure and extended macroblock (EMB) size motion estimation (ME) are introduced in joint model key technology areas software to improve the inter block coding efficiency. Similar to H.264, variable size motion estimation (VS-ME) is still adopted for each 16×16 MB including 16×16, 16×8, 8×16, 8×8, 8×4, 4×8, and 4×4. EMB size ME and VS-ME achieve the highest possible coding efficiency, but result in extremely large coding time which obstructs it from practical use. A fast mode decision algorithm for EMBs based on motion homogeneity is proposed to reduce the computational complexity of ME. The basic idea of the proposed method is to utilize the spatial property of motion field in prediction where EMB size ME and small size ME (including 8×8, 8×4, 4×8 and 4×4) are needed, and only in these regions EMB size ME and small size ME are enabled. The motion field is generated by the corresponding motion vectors in spatial window. Simulation results show that the proposed algorithm can save 55% average computational complexity, with negligible loss of coding efficiency.

Frame Rate Up-Conversion Technique Using Hardware-Efficient Motion Estimator Architecture for Motion Blur Reduction of TFT-LCD

Motion blur in TFT-LCD is caused by sample and hold characteristic, slow response time of liquid crystal, and the inconsistency between object tracking of the human eye and the actual object location. In order to solve this problem, a high frame rate driving method based on motion estimation and motion compensation has been applied to LCD products. However, as the required processing time of motion estimation increases in LCD TV and monitor systems, real-time video image processing becomes more difficult. Frame interpolation through the large macro block (MB) size has limitations to detect small objects. So, this paper proposes the efficient motion estimator architecture which uses seven kinds of macro blocks to enhance the accuracy of motion estimation and combines the parallel processing with pre-computation technology and hardware optimization for high-speed processing. Also, for increased efficiency in the hardware architecture, we employed an I2C (Inter Integrated Circuit) communication unit to control the key parameters easily through the personnel computer. Simulation results show that the critical path at the motion estimator is reduced by about 27.47% compared to the conventional structure. As a result, the proposed motion estimator will be applicable for the high-speed frame interpolation of variable video.

超高精細映像におけるマクロブロックサイズ拡張手法に関する解析的考察

Ultra-high resolution video is expected to be one of the next-generation high quality video formats. Current video coding technology H.264 achieves the maximum amount of coding efficiency from among the existing coding standards. However, even H.264 is not sufficient enough for ultra-high resolution video distribution service due to a lack of coding efficiency. Therefore, an enhanced video coding technology is strongly required to improve the coding efficiency. In the past works, several approaches for extending the macroblock (MB) size have been proposed, and these researches showed that extended MB size technology improved the coding efficiency, especially for high resolution video. However, a clear description of the performance improvement mechanism has yet to be presented. We analytically consider the coding characteristics of an extended MB size scheme for ultra-high resolution video in this paper. We clarified the coding gain mechanism of this technology based on a R-D characteristics analysis. Furthermore, we analytically confirmed that the extended MB size scheme was most effective at high-resolution and low-bitrate video coding. Finally, we conducted a coding experiment and found that the maximum bit reduction ratio reached approximately 15% using an optimal coding control for the extended MB size scheme.

Accurate phase-added stereogram to improve the coherent stereogram

We propose an "accurate" phase-added stereogram, which can be defined as an improved phase-added stereogram. Generally, the macroblock size transformed by the fast Fourier transform is the same as the segmentation size of the phase-added stereogram. However, the proposed method uses a lager macroblock size than does the conventional method to reduce quantization error in discrete spatial frequencies in the spatial frequency domain. Therefore, even when the fast Fourier transform is used for calculation, the quality of the reconstructed image can be improved to be as clear as the Fresnel hologram.

超高精細映像のH.264 FR-Ext符号化を対象とした最大マクロブロックサイズ拡張による符号化効率改善方式

超高精細映像のH.264 FR-Ext符号化を対象とした最大マクロブロックサイズ拡張による符号化効率改善方式

アーカイブス映像の劣化修復システムの開発 アナログＶＴＲ素材の劣化修復

This paper describes a method for restoring the defects inherent in video archives recorded in analog mode. The requirements for the restoration system are that it takes a short time and that it does not cost much. First, the nature and occurrence of the defects are examined for video archives. A restoration method is then proposed that is based on the characteristics of the defects. The method uses temporal and spatial median filters, the differences in luminance levels between the original and filtered images, and the chrominance levels of the original images. It restores not only the defects in small motion areas but also conspicuous white scratches without producing any artifacts. It has a semiautomatic mode, and it enables the selection of the temporal and spatial median filters and the number of frames for the temporal filter or the macroblock size for the spatial filter.

Comparison of MPEG Domain Elements for Low-Level Shot Boundary Detection

The goal of this paper is to justify the reliability of the different elements in the compressed domain used in low-level shot boundary detection. Three elements at different level of decoding, namely, chromatic barycenter, luminance and macroblock size information, are extracted from MPEG video for examination. Overviews with analysis of each element are done, followed by a global threshold sensitivity and detection performance test. To detect the stability of the elements under different circumstances, we utilized statistical methods to compare the different elements, and each element is tested with video clips from different fields. We found that both macroblock size and luminance elements could be unstable under certain conditions, and detection in the color domain is essential for accurate shot boundary detection. By utilizing the approximation for chromatic barycenter, fast and accurate shot boundary detection could be achieved.

An adaptive quantization algorithm for video coding

This paper proposes an adaptive quantization algorithm for video coding using the information obtained from the previously encoded image. Before quantizing the discrete cosine transform coefficients, the properties of reconstruction error of each macro block (MB) are estimated from the previous frame. For the estimation of the error of current MB, a block with the size of MB in the previous frame is chosen. Since the original and reconstructed images of the previous frame are available in the encoder, we can evaluate the tendency of reconstruction error of this block in advance. Then, this error is considered as the expected error of the current MB if it is quantized with the same step size and bit rate. Comparing the error of the MB with the average of overall MBs, if it is larger than the average, a small step size is given for this MB, and vice versa. As a result, the error distribution of the MB is more concentrated to the average, yielding low variance and improved image quality. Especially for low bit applications, the proposed algorithm yields much smaller error variance and higher peak signal-to-noise ratio compared to the conventional TM5. We also propose a modified algorithm for efficient hardware implementation.