MPEG-4 Research Articles

Implementation of multi-standard video decoder on a heterogeneous coarse-grained reconfigurable processor

This paper proposes a task-based hybrid parallel and hybrid pipeline (THPHP) scheme to implement multi-standard video algorithms, including MPEG-2, H.264, and audio video coding standard (AVS), on a heterogeneous coarse-grained reconfigurable processor, called the reconfigurable multimedia system (REMUS). The proposed schemes greatly improve decoding performance and satisfy the real-time requirements of various high-definition (HD) video decoding standards. In THPHP, we propose both a task-based hybrid parallel scheme, in which macro-block (MB)-level, block-level, and sub-block-level decoding tasks are parallelized to improve data processing throughput, and a hybrid pipeline scheme, in which slice-level, MB-level, block-level and sub-block-level computations are pipelined to improve efficiency. Computation-intensive tasks, such as motion compensation, intra prediction, inverse discrete cosine transform, reconstruction, and deblocking filter, are implemented on two reconfigurable processing units, which are the core computing engines of REMUS. Thanks to the proposed schemes, the implementations can achieve H.264 high profile (HP) 1920×1080@30 fps streams, AVS Jizhun profile (JP) 1920×1080@39 fps streams, and MPEG-2 main profile (MP) 1920×1080@41 fps streams when working at 200 MHz frequency. Compared with XPP-III (a commercial reconfigurable processor), when implementing H.264 HD decoding, the performance and energy efficiency on REMUS are improved by 1.81× and 14.3×, respectively.

Cryptanalysis of a video encryption method based on mixing and permutation operations in the DCT domain

Wireless sensor network (WSN) needs efficient and secure and simple algorithms to be implemented in order to assure confidential communications between nodes and base station. The most suitable kind of algorithm seems to be the partial encryption ciphers. MPEG video encryption can be done by selecting the most significant parts of this sequence which are the group of pictures known as the I-frames. In this letter, we study the security of a partial video encryption method by Yang and Sun (Prog Nat Sci 18:1299–1304, 2008) that can be used in video nodes in a WSN. Based on the given analysis, it is demonstrated that the cryptosystem under study has serious weaknesses in the shuffling and the mixing processes which makes it vulnerable to chosen plaintext attack. Through the studied cipher, we question whether practitioners should design their own new ciphers for their specific applications or should they use well-known ciphers and fit them to their applications.

Salient Motion Detection in Compressed Domain

We propose a novel motion saliency framework using DCT coefficients and motion vectors as features from MPEG-2 videos. The DCT coefficients of the luma and chroma components are used to calculate the spatial saliency of a frame while the motion vectors are utilized to refine it. Spatio-temporal similarity maps are calculated separately in order to cater to tracking shots. Results show that the proposed motion saliency framework is computationally nearly an 8-fold improvement over the best performing state-of-the-art method while nearly equalling its performance in identifying salient regions.

Research on MPEG Video Stream Transmission Performance Based on NS-2

Following the deployment of network multimedia applications, such as video conference, simulation research on video stream characteristic is more and more important. MPEG standard encodes the video sequences to frame I, P, and B, and has higher compression rate and bandwidth saving character. MPEG video traffic characteristic and simulation methods are researched in this paper. Network simulation version 2(NS-2) kernels is extended using C/C++ programming language. An MPEG video traffic generator modules and simulation interfaces are designed in NS-2 kernel. Simulation results show that the proposed extension method is feasible and effective.

17-2 算術符号を用いたMPEG-1動画像のロスレス再符号化における確率モデルの簡略化(第17部門画像符号化2)

17-2 算術符号を用いたMPEG-1動画像のロスレス再符号化における確率モデルの簡略化(第17部門画像符号化2)

MPEG-2 to HEVC Video Transcoding With Content-Based Modeling

This paper proposes an efficient MPEG-2 to High Efficiency Video Coding (HEVC) video transcoder. The objective of the transcoder is to migrate the abundant MPEG-2 video content to the emerging HEVC video coding standard. The transcoder introduces a content-based machine learning solution to predict the depth of the HEVC coding units. The proposed transcoder utilizes full re-encoding to find a mapping between the incoming MPEG-2 coding information and the outgoing HEVC depths of the coding units. Once the model is built, a switch to transcoding mode occurs. Hence, the model is content based and varies from one video sequence to another. The transcoder is compared against full re-encoding using the default HEVC fast motion estimation. Using HEVC test sequences, it is shown that a speedup factor of up to 3 is achieved, while reducing the bitrate of the incoming video by around 50%. In comparison to full re-encoding, an average of 3.9% excessive bitrate is encountered with an average PSNR drop of 0.1 dB. Since this is the first work to report on MPEG-2 to HEVC video transcoding, the reported results can be used as a benchmark for future transcoding research.

Online OLED dynamic voltage scaling for video streaming applications on mobile devices

This work proposes an online DVS approach for OLED-based mobile video applications to reduce display power consumption. A time-efficient representative-region based DVS scheme is developed and applied in MPEG video streaming. Based on the proposed scheme, flexible DVS solutions can be adaptively derived according to timing constraints. Experimental results show a 26.9% power reduction while keeping 99.3% frames displayed in high quality.

The burst factor and its impact on buffer performance

In this contribution we introduce the burst factor, which is defined in a general setting, and quantifies the long-term variability, or burstiness, of a packet source. By means of a combination of analytic and simulation results, we will demonstrate that this parameter plays an important role in the calculation of the moments of the amount of work in a buffer, both in a scenario where (a superposition of) MPEG-4 video traces are used as input of the buffer, as well as when the (correlated) arrivals are generated by a stochastic model. As such, the burst factor is a key parameter for buffer dimensioning purposes.

A Joint Rate Control Scheme in a Hybrid Stereoscopic Video Codec System for 3DTV Broadcasting

In this paper, a frame-level joint rate control scheme for both intra- and inter-predictive coding is first introduced for a hybrid video codec system that independently encodes the two-view sequences of a stereoscopic video. The proposed rate control scheme jointly works on the left view encoder of MPEG-2 Video and the right view encoder of an H.264/AVC for stereoscopic video input, and is formulated as optimization problems that allow control of the output bit rates of both encoders in the sense that: 1) the sum of the two decoded video qualities is maximized, and 2) the quality difference is maintained around a desired level for a given target bit budget at the same time. In order to verify the effectiveness of the proposed joint rate scheme, it is compared with an independent rate control scheme. The experimental results show that the joint rate control scheme effectively regulates the output bitstreams of the hybrid encoders based on MPEG-2 Video and H.264/AVC. The joint rate control scheme achieves average 0.71 dB gain in PSNR and 67.07% reduction in the MSE of PSNR difference for I-frame only, average 0.54dB gain and 91.08% reduction for IPPP coding, and average 0.32dB gain and 79.01% reduction for IBBP coding.

Improved MPEG-2 video coding scheme based on compressed sensing

In order to seek for applications in video coding of Compressed Sensing(CS) and improve the coding efficiency of MPEG-2,a CS and MPEG-2 based improved scheme was proposed.The improved video coding scheme chose the method producing an image with smaller Sum of Squared Differences(SSD) as the final reconstruction method between the standard reconstruction method and the Total Variation(TV) minimization algorithm in the pixel domain,which is based on the fact that the original image has sparser gradient than the residual image.The experimental results show that the proposed scheme is efficient for all kinds of video sequences.The improvement of Peak Signal-to-Noise Ratio(PSNR) is greater than 0.5 dB for the sequences with sharp edges,and 0.26 dB~0.41 dB for sequences with smooth areas or complex textures.

Reliable camera motion estimation from compressed MPEG videos using machine learning approach

As an important feature in characterizing video content, camera motion has been widely applied in various multimedia and computer vision applications. A novel method for fast and reliable estimation of camera motion from MPEG videos is proposed, using support vector machine for estimation in a regression model trained on a synthesized sequence. Experiments conducted on real sequences show that the proposed method yields much improved results in estimating camera motions while the difficulty in selecting valid macroblocks and motion vectors is skipped.

Enhancing throughput for streaming applications running on cluster systems

The exploitation of throughput in a parallel application that processes an input data stream is a difficult challenge. For typical coarse-grain applications, where the computation time of tasks is greater than their communication time, the maximum achievable throughput is determined by the maximum task computation time. Thus, the improvement in throughput above this maximum would eventually require the modification of the source code of the tasks. In this work, we address the improvement of throughput by proposing two task replication methodologies that have the target throughput to be achieved as an input parameter. They proceed by generating a new task graph structure that permits the target throughput to be achieved. The first replication mechanism, named DPRM (Data Parallel Replication Mechanism), exploits the inner task data parallelism. The second mechanism, named TCRM (Task Copy Replication Mechanism), creates new execution paths inside the application task graph structure that allows more than one instance of data to be processed concurrently. We evaluate the effectiveness of these mechanisms with three real applications executed in a cluster system: the MPEG2 video compressor, the IVUS (Intra-Vascular Ultra-Sound) medical image application and the BASIZ (Bright and SAtured Images Zone) video processing application. In all these cases, the obtained throughput was greater after applying the proposed replication mechanism than what the application could provide with the original implementation.

Detection of Double Compression in MPEG-4 Videos Based on Markov Statistics

With the spread of powerful and easy-to-use video editing software, digital videos are exposed to various forms of tampering. Nowadays, a considerable proportion of surveillance systems and video cameras have built-in MPEG-4 codec. Therefore, the detection of double compression in MPEG-4 videos as a first step in video forensics research is of significance. In this paper, Markov based features are adopted to detect double compression artifacts, which imply that the original video may have been interpolated. The advantages and limitations of double MPEG-4 compression detection are analyzed. Experimental results have demonstrated that our scheme outperforms most existing methods.

MPEG video shot boundary detection based on motion vectors

First,DC map of I frame was extracted for rough detection of the shots.And then the forward motion compensation vector of P frame was extracted,and Extended Vector Median(EVM) filtering was used for the preprocessing of motion vector.Finally the characteristics of three sports features,exercise intensity value,exercise intensity difference and the direction of motion vector histogram,absolute difference were calculated.Fuzzy inference was introduced to synthesize these three characteristics and classified shots to abrupt-change,gradual-change and no-change ones.The MPEG video shot boundary detection method do not need to decompress the video fully,and extracts information directly from MPEG compressed bit stream,so it is of low computation complexity and high extration speed,which is verified by the experimental results.

Low-Power Reconfigurable Processor Utilizing Variable Dual $V_{\rm DD}$

The dual-VDD technique has already been employed in reconfigurable processors to improve energy efficiency. In this brief, a variable dual-VDD method is proposed to reduce power consumption further through varying the level of the lower VDD (VDDL) according to the application on a processor. It finds out the optimum VDDL mainly based on the utilization times of all arithmetic logic unit operations by this application. In this estimation, the analysis of technology and architecture is highly required as well. Static timing analysis and power analysis were performed on the RPU, a reconfigurable processor designed in 65-nm CMOS technology. It is estimated that the proposed method can reduce the power of its reconfigurable array by 32% on average for the applications of GPS, MPEG2, H.264, and audio video coding standard (AVS). If VDDL is fixed at 0.6-0.75 V, the power reduction rate of the reconfigurable array will be 15% less on average. The area penalty of this method is less than 3%.

Towards Generic Embedded Multiprocessing for RVC-CAL Dataflow Programs

Dataflow languages enable describing signal processing applications in a platform independent fashion, which makes them attractive in today's multiprocessing era. RVC-CAL is a dynamic dataflow language that enables describing complex data-dependent programs such as video decoders. To this date, design automation toolchains for RVC-CAL have enabled creating workstation software, dedicated hardware and embedded application specific multiprocessor implementations out of RVC-CAL programs. However, no solution has been presented for executing RVC-CAL applications on generic embedded multiprocessing platforms. This paper presents a dataflow-based multiprocessor communication model, an architecture prototype that uses it and an automated toolchain for instantiating such a platform and the software for it. The complexity of the platform increases linearly as the number of processors is increased. The experiments in this paper use several instances of the proposed platform, with different numbers of processors. An MPEG-4 video decoder is mapped to the platform and executed on it. Benchmarks are performed on an FPGA board.

DETECTION OF DOUBLE MPEG-2 COMPRESSION BASED ON DISTRIBUTIONS OF DCT COEFFICIENTS

Detection of double compression in digital multimedia is considered to reveal the history of multimedia signal processing, which is very useful in digital forensics. In this paper, distributions of quantized DCT coefficients are analyzed in depth after double MPEG-2 compression with constant bit rate (CBR) mode, and a new algorithm is presented to detect double MPEG-2 compression based on convex patterns in the distribution of quantized DCT coefficients. In order to demonstrate the practical value of our proposed algorithm, two digital video cameras (DV) and two MPEG-2 software coders are utilized to simulate the general process of double MPEG-2 compression. Experiment results show that the proposed scheme can effectively detect doubly MPEG-2 compressed videos with CBR mode and the target output bit rate can vary in a large range.

Fast Channel Zapping with Destination-Oriented Multicast for IP Video Delivery

Channel zapping time is a critical quality of experience (QoE) metric for IP-based video delivery systems such as IPTV. An interesting zapping acceleration scheme based on time-shifted subchannels (TSS) was recently proposed, which can ensure a zapping delay bound as well as maintain the picture quality during zapping. However, the behaviors of the TSS-based scheme have not been fully studied yet. Furthermore, the existing TSS-based implementation adopts the traditional IP multicast, which is not scalable for a large-scale distributed system. Corresponding to such issues, this paper makes contributions in two aspects. First, we resort to theoretical analysis to understand the fundamental properties of the TSS-based service model. We show that there exists an optimal subchannel data rate which minimizes the redundant traffic transmitted over subchannels. Moreover, we reveal a start-up effect, where the existing operation pattern in the TSS-based model could violate the zapping delay bound. With a solution proposed to resolve the start-up effect, we rigorously prove that a zapping delay bound equal to the subchannel time shift is guaranteed by the updated TSS-based model. Second, we propose a destination-oriented-multicast (DOM) assisted zapping acceleration (DAZA) scheme for a scalable TSS-based implementation, where a subscriber can seamlessly migrate from a subchannel to the main channel after zapping without any control message exchange over the network. Moreover, the subchannel selection in DAZA is independent of the zapping request signaling delay, resulting in improved robustness and reduced messaging overhead in a distributed environment. We implement DAZA in ns-2 and multicast an MPEG-4 video stream over a practical network topology. Extensive simulation results are presented to demonstrate the validity of our analysis and DAZA scheme.

Analytical model for MPEG video frame loss rates and playback interruptions on packet networks

This paper presents and studies objective video quality evaluation techniques for a network where frame losses can be considered independent, for example a best effort not heavy loaded packet switching network. The total or partial loss of a frame's information affects the quality of video playback, as the frame cannot be decoded and other frames that depend on it cannot be correctly decoded too. Therefore, during some time the video playback has errors in the image and the user will perceive them as interruptions. In this paper, the total number of decoded frames and the video playback interruptions duration will be considered important parameters to quantify the video quality. The analytical formulation for them will be presented and the importance of considering them together will be highlighted.

Novel MPEG-4 video cross-layer algorithm in wireless networks

A novel MPEG-4 video cross-layer algorithm MVCLA is applied in the wireless network platform to approach the higher quality of service QoS in various prioritised traffic flow of MPEG-4 video applications. Even the popular availability of delivering the wireless network access data by the enhanced distributed coordination access EDCA mechanism function, the proposed MVCLA considers two variant conditions i.e., data packets and network traffic load to tune the contention-based parameters of cross-layers. The queue space does not effectively resume the transmission quality for the most important video media when the traffic flow is heavy. Our proposed regulation way dynamically retained the most important image traffic flow information in various conditions. The access control AC queue is flexibly allocated for the transmission purposes while the network channel is busy. The novel tuning algorithm is not only to ensure the high-speed for the most important packets to pull up the QoS level in several video transmission applications, but also efficiently provide the higher utilisation of the queue length. Finally, higher QoS of MPEG-4 video application is actually to verify the great simulation by the developed MVCLA.