Real-time MPEG Research Articles

Commutative encryption based video encoding technique with high-efficiency & video adaptation capabilities

Before selecting any algorithm to be used for encryption in multimedia application systems, a thorough analysis of the application must be performed to determine what level of security is required for it to work securely. As a result, after determining the necessary security levels, a careful algorithm selection must be made. The algorithm chosen will have an effect on the speed of the coder-decoder-codec. As a result, it is critical to do so before deciding on an encryption method. The algorithms used in this paper improve the overall efficiency of video encoding scheme and it takes less time comparatively with exiting algorithm approach and experiment result show it take less computation time. Proposed algorithm implemented on MATLAB platform and, performance of the proposed algorithms in order to meet the requirement of real-time MPEG decoding, we have optimized the video frame (I Frame, B Frame) with video adaptation capabilities which provide the facility to run the video in any platform. The proposed algorithms are expected to be widely used in the future to provide security for video-on-demand applications and pay-per-view programs. It can be extended to use it as non-MPEG compression schemes such as H.263 for video-conferencing applications.

Fast‐efficient shape error concealment technique based on block classification

This study presents a fast-efficient error concealment method for recovering information related to shape. The proposed technique comprises block classification, edge direction interpolation and filtering interpolation. Missing blocks are classified into four categories: transparent, opaque, edge and isolated blocks. Most of the computation is spent on edge blocks and isolated blocks to maximise the cost and performance tradeoff. For the recovery of edge blocks, the edge slope is computed by referring to the nearest available block, from which the missing shape is interpolated parallel to the edge. Isolated blocks are dealt with using a cascade filter to approximate the actual shape. Experimental results show that the proposed method provides better cost performance in the restoration of shapes than that afforded by comparable algorithms, both in numerical parameters and the resulting shapes. The processing speed is approximately two to three times faster than previous methods and low computational load makes the proposed technique applicable to real-time MPEG-4 systems.

Embedded Real-Time MPEG-4 Decoder Based on ADSP-BF527

In this paper, we propose an embedded real-time MPEG-4 decoder based on ADSP-BF527 Blackfin DSP. In order to achieve the real-time requirement of MPEG-4 decoding, we modify and optimize the decoding modules. Firstly, we analyze the number of operations for various modules, and then use two buffer groups (BG) as parallel decoding mechanism of broadcast transformation. Finally, we make use of direct memory access (DMA) to carry out program steps. Experimental results demonstrate that the proposed method can decode a CIF video which reduces approximately 40.3 MHz core cycles. In addition, the decoded frame playing rate can increase from 3 fps to 25 fps when applied the PPI procedure. The playing rate can reach above 30 fps as using QCIF video so that the proposed method can achieve a real-time decoder and player.

A Study for the MPEG-4 Library to operate in real-time on the DSP

Informations of multimedia centering in the images, are combined acoustic and letter, etc. Although the network advances and the capacity of the storage media extends, these huge informations will not be able to accommodate. From meaning which is like this, International standards for the compression and a multiplexing of image, acoustic and voice H261 where admits standard, JPEG, JBIG, MPEG-l, MPEG-2, MPEG-4 and H263, G series etc, are core techniques of multimedia. At initial step of the base technique which creates the base of like this multimedia service time, we developed the real-time MPEG-4 transmission systems to provides real-time MPEG-4 multimedia services. This system means becomes the base technique which hereafter is developed and is applied various system. This system Will be able to apply from a videoconference, a building protection system and a VOD video system to use the Internet. And, They, the image sensing, embedded linux, and MPEG4 software, will become sourceful technique to develop the different system.

Visual acuity, contrast sensitivity, and range performance with compressed motion video

Video of visual acuity (VA) and contrast sensitivity (CS) test charts in a complex background was recorded using a CCD color camera mounted on a computer-controlled tripod and was fed into real-time MPEG-2 compression/decompression equipment. The test charts were based on the triangle orientation discrimination (TOD) test method and contained triangle test patterns of different sizes and contrasts in four possible orientations. In a perception experiment, observers judged the orientation of the triangles in order to determine VA and CS thresholds at the 75% correct level. Three camera velocities (0, 1.0, and 2.0 deg/s, or 0, 4.1, and 8.1 pixels/frame) and four compression rates (no compression, 4 Mb/s, 2 Mb/s, and 1 Mb/s) were used. VA is shown to be rather robust to any combination of motion and compression. CS, however, dramatically decreases when motion is combined with high compression ratios. The measured thresholds were fed into the TOD target acquisition model to predict the effect of motion and compression on acquisition ranges for tactical military vehicles. The effect of compression on static performance is limited but strong with motion video. The data suggest that with the MPEG2 algorithm, the emphasis is on the preservation of image detail at the cost of contrast loss.

Long-Range Prediction for Real-Time MPEG Video Traffic: An $H_{\infty}$ Filter Approach

A novel prediction scheme is proposed for real-time MPEG video to predict the burst and long-range dependent traffic. The trend and periodic characteristics of MPEG video traffic are fully captured by a proposed stochastic state-space dynamic model. Then a recursive Hinfin filtering algorithm is proposed to estimate traffic for long-range prediction. Simulation results based on real MPEG traffic data show that the proposed scheme has superior performance and lower complexity than some adaptive neural network methods, such as TDNN, NARX, and Elman neural networks.

Prediction of MPEG video traffic over ATM networks using dynamic bilinear recurrent neural network

Dynamic bilinear recurrent neural network (D-BLRNN) with a dynamic learning gain and optimization layer by layer procedure is proposed and applied to MPEG video traffic prediction over ATM networks in this paper. Since the BLRNN is based on the bilinear polynomial, it has been more effectively used in modeling highly non-linear systems with time-series characteristics than the conventional multi-layered perceptron type neural network (MLPNN). D-BLRNN is proposed to enhance the prediction capability of the BLRNN further by introducing dynamic learning control and optimization layer by layer procedure. Since ATM networks have a bursty nature because of their variable bit rate (VBR) and MPEG video traffic has a typical VBR characteristics, the proposed D-BLRNN can be an optimal candidate for the MPEG traffic prediction problem. In the experiment, the proposed D-BLRNN is applied to a real world MPEG traffic problem (‘MPEG.data’ from the movie ‘Star Wars’) as an on-line learning and a prediction problem. When compared with other prediction schemes including MLPNN and pipelined recursive neural network, the D-BLRNN improves the prediction error by 60% or more in most cases. The results may imply that the D-BLRNN based predictor proposed in this paper is promising and practically reliable tool for predicting bursty sources including real-time MPEG video traffic.

A new adaptive watermarking for real-time MPEG videos

Based on the classic block-adaptive-video watermarking schemes, an improved fast adaptive video watermarking is proposed for real-time application by combining with the MPEG standards. In this scheme, a novel delicate block classification criterion completely based on the MPEG standards is used to select suitable watermarking positions, and watermarks are embedded into the video streams with redundant styles through exchanging the EQSP (equal quantization step position). Experimental results show that our improved work has better performances than the previous methods regarding complexity, robustness and visual quality for copyright protection in VOD (video on demand) application.

Implementation of SDTV Video Encoder with Real-Time Constant and Variable Bit-Rate Control

The digital standard definition television (SDTV) encoder is a very important part of the digital TV broadcast chain. Most real-time MPEG-2 encoders are designed to perform in a constant bit-rate (CBR) mode. But an even better compressed stream can be created by employing a variable bit-rate (VBR) encoding algorithm. VBR can be exploited as a means of achieving statistical multiplexing for digital broadcast satellites. This paper suggests an implementation procedure of an SDTV video encoder and proposes a novel VBR bit-allocation strategy that could be implemented in this encoder system. First, using a rate-quantization model and rate-quantization perceptual model, a real-time VBR bit-allocation strategy is deduced. In this strategy, more (or fewer) bits are allocated to "difficult-to-encode" (or "easy-to-encode") groups of pictures (GOPs), which are distinguished according to the estimated encoding complexity of the GOPs. After allocating an appropriate number of bits to each GOP by using this VBR bit-allocation strategy, we use a CBR rate control algorithm to allocate a number of bits and select a quantization scaler for each picture of a GOP. Then smooth visual quality is achieved not only in a GOP but also in the whole video sequence. Second, the system implementation of an SDTV video encoder including a video input module, a video encoding module, a system control and rate control module (SCRCM), and a PES packetizing module is described. We also discuss in detail how to implement our real-time VBR bit-allocation strategy in the SCRCM. Finally, experimental results demonstrate that our proposed VBR encoder displays a better performance than the CBR encoder.

A Hardware Implementation of a Content-Based Motion Estimation Algorithm for Real-Time MPEG-4 Video Coding

Power efficiency and real-time processing capability are two major issues in today's mobile video applications. We proposed a novel Motion Estimation (ME) engine for power-efficient real-time MPEG-4 video coding based on our previously proposed content-based ME algorithm [8], [13]. By adopting Full Search (FS) and Three Step Search (TSS) alternatively according to the nature of video contents, this algorithm keeps the visual quality very close to that of FS with only 3% of its computational power. We designed a flexible Block Matching (BM) Unit with 16-PE SIMD data path so that the adaptive ME can be performed at a much lower clock frequency and hardware cost as compared with previous FS based work. To reduce the energy cost caused by excessive external memory access, on-chip SRAM is also utilized and optimized for parallel processing in the BM Unit. The ME engine is fabricated with TSMC 0.18 μm technology. When processing QCIF (15 fps) video, the estimated power is 2.88 [email protected] MHz (supply voltage: 1.62 V). It is believed to be a favorable contribution to the video encoder LSI design for mobile applications.

Real-time low-complexity adaptive approach for enhanced QoS and error resilience in MPEG-2 video transport over RTP networks

In this paper, the problems of redundancy allocation for providing effective error-resilience and service class distribution for enhanced quality of service (QoS) in real-time MPEG-2 video transport are addressed. A real-time low-complexity content-based adaptive error-resilient approach is proposed for the transport of MPEG-2 video streams, encapsulated using real-time transport protocol (RTP) and delivered over heterogeneous networks. An algorithm is derived using spatial and temporal properties of MPEG-2 video for assigning weights to each packet based on the estimated perceptual error. These weights, which indicate the relative importance of RTP packets, together with the communication channel characteristics are used to determine the allocation of resources for providing improved error-resilience and for assigning data packets to various classes of service in order to enhance the quality of transmission. Parameters extracted from the RTP header are used to determine the weights, so that the proposed algorithm can be implemented in real-time. This algorithm is used for adaptively allocating redundant forward error correction packets as well as for marking and forwarding of RTP packets in differentiated services (DiffServ). Simulation results are presented to show the significant improvement in performance based on our proposed approach to video transport.

The plenoptic video

This paper presents a system for capturing and rendering a dynamic image-based representation called the plenoptic video. It is a simplified light field for dynamic environments, where user viewpoints are constrained to the camera plane of a linear array of video cameras. Important issues such as multiple camera calibration, real-time compression, decompression and rendering are addressed. The system consists of a camera array of eight Sony CCX-Z11 CCD cameras and eight Pentium 4 1.8-GHz computers connected together through a 100 Base-T local area network. It is possible to perform software-assisted real-time MPEG-2 compression at a resolution of (720/spl times/480). Using selective transmission, we are able to stream continuously plenoptic video with (256/spl times/256) resolution at a rate of 15 f/s over the network. For rendering from raw data on the hard disk, real-time rendering can be achieved with a resolution of (720/spl times/480) and a rate of 15 f/s. A new compression algorithm using both temporal and spatial predictions is also proposed for the efficient compression of the plenoptic videos. Experimental results demonstrate the usefulness of the proposed parallel processing based system in capturing and rendering high-quality dynamic image-based representations using off-the-shelf equipment, and its potential applications in visualization and immersive television systems.

A real-time video multicast architecture for assured forwarding services

This paper presents our work on developing an architecture for multicasting real-time MPEG4 over IP networks that provide service differentiation. In particular, this work is targeted at assured forwarding (AF) style services. This work is an attempt to find a simple solution to the problem of multicast congestion control of real-time traffic by exploiting the service differentiation capabilities of AF networks. Our architecture assumes loss differentiation in the network and assumes the network's ability to provide explicit congestion notification messages to the sender. We do not consider policing/shaping at the edge routers. Rather, we consider a more general case where packet marking and flow control are provided at the senders. For this network model, we built an end-to-end architecture and developed a rate-adaptation algorithm that can operate in both unicast and multicast applications with a minor modification. The simulation results show how the rate-adaptation algorithm accommodates different receivers with different networking capabilities and provides receivers with different levels of quality by taking advantage of the queue management capabilities of the AF service. We test how the architecture scales to a large number of receivers, how multiple multicast sessions interact, and how it interacts with TCP.

Hardwired MPEG-4 repetitive padding

We consider two hardwired solutions for repetitive padding, a performance restricting algorithm for real time MPEG-4 execution. The first solution regards application specific implementations, the second regards general purpose processing. For the application specific implementations we propose a systolic array structure. To determine the chip area and speed, we have synthesized its VHDL models for two field-programmable gate array families-Xilinx and Altera. Depending on the implemented configuration, the unit can process between 77 K and 950 K macroblocks per second (MB/s) when mapped on FPGA chips containing less than 10 K logical gates and frequency capabilities below 100 MHz. The second approach regards an augmentation of a general-purpose arithmetic logical units with an extra functionality added to perform repetitive padding. At trivial hardware costs of a few hundred 2/spl times/2 AND-OR logic gates, we achieve an order of magnitude speed-up compared to nonaugmented general purpose processor padding. The proposed hardware solutions meet the requirements of all MPEG-4 visual profile levels. Both approaches have been proven to be scalable and fit into different architectural concepts and operand widths.

A multisymbol context-based arithmetic coding architecture for MPEG-4 shape coding

MPEG-4 shape coding comprises context-based arithmetic encoding (CAE) as its centerpiece. Since the CAE algorithm has a complicated coding procedure and strong data dependency, it is hard to exploit its pipeline and parallel facilities. Furthermore, to encode multiple symbols within one clock cycle, it needs to overcome the issues of extracting multiple contexts of these symbols, deriving multiple probabilities from these contexts, and performing multiple multiplicative range update operations. This paper presents an efficient pipelined multisymbol CAE architecture for real-time MPEG-4 shape encoding. The proposed design is based on the inherent characteristics of binary alpha blocks as well as the numerical properties of the probabilities indexed by the contexts, and it is capable of encoding either a singe symbol or multiple symbols within each clock cycle. To overcome the aforementioned issues under the consideration of the hardware cost and the critical path delay, only symbols with a particular set of contexts are chosen to be processed simultaneously within the same clock cycle. Theoretical analysis shows that the majority of symbols have contexts belonging to this particular set, and therefore CAE processing can be significantly accelerated. An example VLSI implementation of proposed architecture that encodes two symbols within each clock cycle without sacrificing the clock rate can achieve a speedup of 1.47 in comparison with traditional CAE architectures. This particular two-symbol design can support MPEG-4 Main Profile at levels 3 and 4 under extreme and typical conditions, respectively. When synthesized from Verilog RTL design by using TSMC 0.35-/spl mu/m 1P4M CMOS technology, the design can run at 90 MHz.

MPEG-2 real-time software CODEC for full-duplex transmission application over IP networks

This paper proposes a real-time MPEG-2 software CODEC for full-duplex transmission applications, and evaluates its performance and usefulness. The CODEC consists of a high-speed encodersdecoder, an IP sendersreceiver, and an error recovery controller. Each encodersdecoder is accelerated and optimized by exploiting fast algorithms and instruction-level parallelism. The IP sendersreceiver combination achieves low delay owing to the direct translating of each elementary stream of video and audio into UDPsIP packets. The error recovery controller carries out simple but powerful error tolerance against packet loss over IP networks. This CODEC attains low delay of 99 ms (M = 1, N = 1) to 165 ms (M = 3, N = 3) including input, encoding, transmitting, decoding, and output delays, and maintains a normal frame rate of 30 fps (frames per second) and more than 20 fps even under a fairly heavy network load. It provides sufficiently good performance for use as a real-time full NTSC-size CODEC on a PC of at least 1.2-GHz CPU. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(2): 33–41, 2005; Published online in Wiley InterScience (). DOI 10.1002sscj.20151

MPEG-2 real-time software CODEC for full-duplex transmission application over IP networks

This paper proposes a real-time MPEG-2 software CODEC for full-duplex transmission applications, and evaluates its performance and usefulness. The CODEC consists of a high-speed encoder/decoder, an IP sender/receiver, and an error recovery controller. Each encoder/decoder is accelerated and optimized by exploiting fast algorithms and instruction-level parallelism. The IP sender/receiver combination achieves low delay owing to the direct translating of each elementary stream of video and audio into UDP/IP packets. The error recovery controller carries out simple but powerful error tolerance against packet loss over IP networks. This CODEC attains low delay of 99 ms (M = 1, N = 1) to 165 ms (M = 3, N = 3) including input, encoding, transmitting, decoding, and output delays, and maintains a normal frame rate of 30 fps (frames per second) and more than 20 fps even under a fairly heavy network load. It provides sufficiently good performance for use as a real-time full NTSC-size CODEC on a PC of at least 1.2-GHz CPU. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(2): 33–41, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20151

A low complexity design of psycho-acoustic model for MPEG-2/4 advanced audio coding

The paper presents a new low complexity design of psycho-acoustic model (PAM), which is the key technology for MPEG-2/4 advanced audio coding (AAC) encoding. The real-time constraint of MPEG AAC leads to a heavy computational bottleneck on today's portable devices. To overcome this problem, design analysis and optimization of PAM are addressed at the algorithmic level. First, the dominant calculation of spreading function is replaced with small look-up tables. Second, modified-discrete-cosine-transform-based (MDCT-based) PAM with block type decision in frequency domain is proposed to reduce the overall AAC encoder complexity and maintain the quality. This technique is different from the traditional methods. The computational complexity of PAM is reduced by 82% in total. The proposed design could be implemented in a real-time MPEG-2/4 AAC stereo encoder at low complexity profile and bit rate 128 kb/s with computational complexity of less than 20 MOPS while maintaining CD quality.

Improved Bit Rate Control for Real-Time MPEG Watermarking

The alteration of compressed video bitstream due to embedding of digital watermark tends to produce unpredictable video bit rate variations which may in turn lead to video playback buffer overflow/underflow or transmission bandwidth violation problems. This paper presents a novel bit rate control technique for real-time MPEG watermarking applications. In our experiments, spread spectrum watermarks are embedded in the quantized DCT domain without requantization and motion reestimation to achieve fast watermarking. The proposed bit rate control scheme evaluates the combined bit lengths of a set of multiple watermarked VLC codewords, and successively replaces watermarked VLC codewords having the largest increase in bit length with their corresponding unmarked VLC codewords until a target bit length is achieved. The proposed method offers flexibility and scalability, which are neglected by similar works reported in the literature. Experimental results show that the proposed bit rate control scheme is effective in meeting the bit rate targets and capable of improving the watermark detection robustness for different video contents compressed at different bit rates.

Fast Video Segmentation Algorithm With Shadow Cancellation, Global Motion Compensation, and Adaptive Threshold Techniques

Automatic video segmentation plays an important role in real-time MPEG-4 encoding systems. Several video segmentation algorithms have been proposed; however, most of them are not suitable for real-time applications because of high computation load and many parameters needed to be set in advance. This paper presents a fast video segmentation algorithm for MPEG-4 camera systems. With change detection and background registration techniques, this algorithm can give satisfying segmentation results with low computation load. The processing speed of 40 QCIF frames per second can be achieved on a personal computer with an 800 MHz Pentium-III processor. Besides, it has shadow cancellation mode, which can deal with light changing effect and shadow effect. A fast global motion compensation algorithm is also included in this algorithm to make it applicable in slight moving camera situations. Furthermore, the required parameters can be decided automatically, which can enhance the proposed algorithm to have adaptive threshold ability. It can be integrated into MPEG-4 videophone systems and digital cameras.