Modified EZW coding for the M-band wavelet transform and its application to image compression

In this paper, we propose an embedded variable bit-rate (VBR) audio coder to provide the fittest quality of service (QoS) and better connectivity of service for the ubiquitous speech communications. It has scalable bandwidth for narrowband to wideband speech signal, and embedded 8 32 kbit/s VBR corresponding to the network condition and terminal capacity. For the design of the embedded VBR coder, the narrowband signals are compressed by an existing standard speech coding method for the compatibility with G.729 coder, and then the other signals are compressed hierarchically on the basis of CELP enhancement and transform coding with temporal noise shaping (TNS) method. By the objective and subjective quality tests, it is shown that the proposed embedded VBR audio coder provides a reasonable quality compared with existing audio coders such as G.722 and G.722.2 in terms of mean opinion score (MOS) and perceptual evaluation of speech quality of wideband (PESQ-WB).

The authors present the bit-rate characteristics of variable bit-rate (VBR) MPEG-1 compatible video intended for asynchronous transfer mode (ATM) network applications. The VBR coding mode for MPEG video is of special interest in teleconferencing and workstation multimedia applications requiring constant image quality, low delay, and/or integrated multimedia transport. Simulation data are provided for a 5-10 Mbps CCIR601 VBR MPEG encoder appropriate for standard-quality TV broadcasting or multimedia applications. The results presented include bit-rate traces and signal-to-noise ratio for typical test sequences, along with summary bit-rate statistics. The performance of frame-based peak rate control as a traffic shaping method is studied. Signal-to-noise ratio obtained with VBR and constant bit-rate coding modes operating at the same average bit-rate is also given for purposes of comparison. >

Layered Coding Schemes for Video Transmission on ATM Networks

The bandwidth flexibility offered by the asynchronous transfer mode (ATM) technique makes it possible to select picture quality and bandwidth over a wide range in a simple and straightforward manner. A prototype model of a video codec was developed that demonstrates the feasibility of both variable bit rate (VBR) coding and user-selectable picture quality. The VBR coding algorithm is discussed and it is shown how a stabilized quality is achieved and how this quality and associated bandwidth can be selected by the user. How error propagation is limited to reduce the visibility of cell losses is also discussed. Interfaces with the ATM network are analyzed, with emphasis on decoder synchronization and absorption of cell delay jitter. The VBR codec offers very good picture quality for videophony applications at an equivalent load of 5.9 Mb/s. Picture quality remains relatively constant, even for heavy motion. >

Multi-band (M-band) wavelet domain presents a novelty to host the watermark. In this paper, a new family of M-band wavelets, which is symmetric and parameterized with a variable /spl lambda/, is proposed and applied to image watermarking. The parameter /spl lambda/ also can be used as a key in watermark detection to improve the security of watermark. The multi-resolution analysis (MRA) of M-band wavelet transform, integrating with the CDMA (code division multiple access) encoding techniques is studied and employed to watermarking. The security, imperceptibility, and the robustness against JPEG compression and Gaussian noise, are analyzed for the proposed watermarking scheme. The experiments of watermarking based on M-band wavelet transform provide more encouraging results than those based on 2-band wavelets.

The paper presents an implementation of a perceptually transparent variable bit rate (VBR) audio coder that complies with the MPEG-4 advanced audio coding (AAC) standard. The coder is based on the MPEG-4 reference software source code of CBR coder. With small modifications in the reference source code a coder guaranteeing perceptual transparency is achieved at compression ratios considerably better than that of the reference CBR coder. Comparison tests indicate that files generated by the perceptually transparent VBR coder applied to a standard set of test items are considerably smaller (in average 24%) than the smallest CBR files of the same quality.

Two versions [1],[2] of Low-Delay Code-Excited Linear Predictive (LD-CELP) coders have been recently suggested as candidates for the CCITT 16 kbit/s speech coding standard. The goal of this standard is to cover a long list of possible applications like mobile radio, video-phone, Digital Circuit Multiplication Equipment (DCME), etc.. Many of these applications have different requirements so it has been difficult to define the performance requirements and objectives for a unique algorithm which will be suitable for a large variety of these applications. Thus it was suggested [3] and accepted as an objective of the standard that the adopted algorithm will have a nominal rate of 16 Kbit/s but can operate at bit rates higher and lower than the nominal rate. This may enable a more optimal implementation for each specific application and provide a better basis for acceptance of the standard by various user groups. For example, Variable-Bit-Rate (VBR) coding can be used to add an error correction/detection information for noisy channel applications like mobile radio. Another example is in DCME systems, where VBR coding can avoid speech clipping during overload traffic periods, and can improve speech quality during underload periods.

Variable bit rate (VBR) coding techniques have received great research interest as very promising tools for transmitting bursty multimedia traffic with low bandwidth requirements over a communication link. Statistically multiplexing the multimedia bursty traffic is a very efficient method of maximizing the utilization of the link capacity. The application of computer simulation techniques in analyzing a rate-based access control scheme for multimedia traffic such as voice traffic is discussed. The control scheme regulates the packetized bursty traffic at the user network interface of the link. Using a suitable congestion measure, namely, the multiplexer buffer length, the scheme dynamically controls the arrival rate by switching the coder to a different compression ratio (i.e., changing the coding rate). VBR coding methods can be adaptively adjusted to transmit at a lower rate with very little degradation in the voice quality. Reported results prove that the scheme greatly improves the link performance, in terms of reducing the probability of call blocking and enhancing the statistical multiplexing gain.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In this paper, we introduce an efficient lossy coding procedure specifically tailored for handling video sequences of automotive high-dynamic range (HDR) image sensors in advanced driver-assistance systems (ADASs) for autonomous vehicles. Nowadays, mainly for security reasons, lossless compression is used in the automotive industry. However, it offers very low compression rates. To obtain higher compression rates, we suggest using lossy codecs, especially when testing image processing algorithms in software in-the-loop (SiL) or hardware-in-the-loop (HiL) conditions. Our approach leverages the high-quality VP9 codec, operating in two distinct modes: grayscale image compression for automatic image analysis and color (in RGB format) image compression for manual analysis. In both modes, images are acquired from the automotive-specific RCCC (red, clear, clear, clear) image sensor. The codec is designed to achieve a controlled image quality and state-of-the-art compression ratios while maintaining real-time feasibility. In automotive applications, the inherent data loss poses challenges associated with lossy codecs, particularly in rapidly changing scenes with intricate details. To address this, we propose configuring the lossy codecs in variable bitrate (VBR) mode with a constrained quality (CQ) parameter. By adjusting the quantization parameter, users can tailor the codec behavior to their specific application requirements. In this context, a detailed analysis of the quality of lossy compressed images in terms of the structural similarity index metric (SSIM) and the peak signal-to-noise ratio (PSNR) metrics is presented. With this analysis, we extracted some codec parameters, which have an important impact on preservation of video quality and compression ratio. The proposed compression settings are very efficient: the compression ratios vary from 51 to 7765 for grayscale image mode and from 4.51 to 602.6 for RGB image mode, depending on the specified output image quality settings. We reached 129 frames per second (fps) for compression and 315 fps for decompression in grayscale mode and 102 fps for compression and 121 fps for decompression in the RGB mode. These make it possible to achieve a much higher compression ratio compared to lossless compression while maintaining control over image quality.

The advent of the asynchronous time division (ATM) concept has created the opportunity to use variable bit rate (VBR) coding techniques for the coding of video services in broadband networks. The principles of VBR coding are explained, and the benefits-stabilized picture quality combined with a high bandwidth efficiency-are indicated. The results obtained with a hardware model of a VBR video codec are presented, and statistical multiplexing gain figures are given. A bandwidth allocation scheme is proposed that is based on the statistical characterization and policing of the VBR sources. It is concluded that this scheme offers high performance with a limited impact on the network and encoder complexity. >

In this paper, we have discussed the comparative study of Fast Discrete Cosine Transform (FDCT).The proposed Algorithm investigate the performance evaluation of quantization based Fast DCT and variable block size with different no of iterations based image compression Techniques. This paper has been devoted to improve image compression at low lower no of iterations and higher pixel values. The numerical analysis of such algorithms is carried out by measuring Peak Signal to Noise Ratio (PSNR), Compression Ratio (CR) and CPU processing time. In this paper we have elaborated about the compression ratio with different no iterations. We can evaluate the higher compression ratio results more effectively with lower iteration and higher pixel values than that of quality of image respectively. Image quality will be degraded at higher iteration but compression ratio is better as compare to other algorithms. Different no of iterations and quantized matrix and variable block size are chosen using FDCT for calculating MSE, PSNR and Compression Ratio for achieving the highest image quality and Compression Ratio under the same algorithm. The proposed algorithm significantly raises the PSNR and minimizes the MSE at lower iterations but as above discussion main theory is that Compression Ratio increases at higher iterations and quality of image will not be maintained at higher iterations. We have also calculated the CPU processing time for processing of image compression to find the complexity of algorithm. We have Tested this algorithm two test Images fruit with 512 × 512 pixel frame and Lena image with 256 × 256 pixel frames. Thus, we can also conclude that at the same compression ratio the difference between original and decompressed image goes on decreasing, as there is increase in image resolution.

In this paper, we propose an algorithm for one-pass VBR (variable bit rate) MPEG video encoding. We use two techniques to enhance the picture quality in the one-pass VBR coding. One is a scene adaptive dynamic GOP (group of picture) structure control technique according to the picture characteristics estimated by macroblock activity information. The other is a precise bit budget prediction technique for appropriate bit allocation based on the activity and motion characteristics analysis. Since the processing speed of the proposed algorithm is almost equal to that of the conventional CBR (constant bit rate) MPEG encoder, fast VBR encoding can be realized with better picture quality than that of CBR.

The emerging IEEE 802.15.4 standard is designed for low data rate, low power consumption and low cost wireless personal area networks (WPANs). Video transmission over such networks is considered an issue since video traffic demands high data rates. In this paper, the TES (transform-expand-sample) methodology is used to model low rate MPEG4 video. The performance of a surveillance video application is evaluated over wireless Zigbee networks. A rate control algorithm (RC-VBR) adapted to MPEG4 variable bit rate (VBR) video coders is studied over Zigbee networks. The algorithm avoids unpredictable rate variations of the VBR coding and removes the coding delay in constant bit-rate (CBR) coders. A region of interest (ROI) encoding is added to the rate control algorithm in order to capture the important parts of the frame which is suitable for IEEE 802.15.4 (Zigbee) networks. Zigbee networks will enable a large number of applications for surveillance networks. The ns-2 simulator is used to test and validate the MPEG4 real video and modeled video over ad hoc Zigbee networks and to test the different algorithms.

Video streaming has already been very popular on the Internet through services such as news bulletins from different parts of the world and on-demand music-video clips. With rapidly developing wireless technologies, video streaming to mobile devices will be very common. We investigate the self-similar scaling behavior that is present in variable bit rate (VBR) MPEG-4 video. As the usage of video services over packet-based wireless networks increases, new workload models will be necessary to study the quality of service aspects of video traffic. A key finding of our study is that MPEG-4 video encoder output traffic has fractal behavior and this behavior exists regardless of the compression ratio.

Task-based model/human observer evaluation of SPIHT wavelet compression with human visual system-based quantization 1