Explosive growth in online services has recently renewed the interest for building modular and eecient network server systems. System design complications coupled with excessive expectations from technological progress previously discouraged the development of media servers eeciently supporting video streams with variable bit rates. In this paper, we describe the design of a distributed media s...

in this paper, the effects of scintillation phenomena on bit error rate (ber) and signal to noise ratio (snr), which are essential characteristics in free space optical (fso) communication system, are studied. until now various methods have been introduced to decrease ber and increase the link's reliability. optimizing snr is one of the fundamental methods to decrease ber value. intensity fluct...

This paper presents a novel multi-band CELP coder with the following characteristics: wideband coding (6.5 kHz), variable bit rate (VBR) coding (10-24 kbps), low-delay (10 ms), embeddibility, and perceptually based dynamic bit allocation. The excitation signal of the linear prediction filter is the vector sum of eight off-line pre-filtered bandpass excitation vectors. The eight excitation codeb...

A bit allocation method is proposed to minimize the propagation of quantization error and thereafter to increase the average quality of encoded video in variable bitrate video applications. In comparison with constant bitrate video, a variable bitrate video can provide better visual quality and coding efficiency for compressed video. Furthermore, while more variation in bitrate is possible we h...

In many applications, video sequences must be transmitted constant bit rate channels (CBR). Therefore, rate control has to be used to regulate the variable bit rate of coded stream. In this paper, we propose an effective bit-rate control algorithm in H.264/AVC for CBR transmission. Our algorithm jointly decides mode and quantization using rate distortion optimization (RDO) technique. And to red...

Quality of Service (QoS) provided by the IEEE 802.11e amendment and by the proposed HCF Controlled Channel Access (HCCA) reference scheduler is tailored for Constant Bit Rate traffic streams. Moreover the numerous alternative scheduling algorithms are not suitable to serve Variable Bit Rate (VBR) traffic streams with the required QoS and real-time guarantees. This paper presents Immediate Dynam...

We describe a novel procedure for variable rate encoding of a speech signal starting from the discrete time wavelet extrema representation. We describe the bit reduction achievable by thresholding the extrema signal. We also demonstrate that the thresholding procedure provides a \denoising" eeect. We then reduce the bit rate further by using a bit allocation scheme that adopts a model for the e...

The ATM Forum and ITU-T specify multiple service categories of B-ISDN, such as CBR (constant bit rate), RT-VBR (realtime variable bit rate), NRT-VBR-COD/CLD (non-realtime variable bit rate connection-oriented data/connectionless data), ABR (available bit rate), and UBR (unspecified bit rate). Each service category specifies different traffic parameters and QoS parameters : bandwidth, end-to-end...

The selection of an optimal regular-shaped pattern set for very low bit-rate video coding, focusing on moving regions has been the objective of much recent research in order to try and improve bit-rate eficieciency. Selecting the optimal pattern set however, is an NP hard problem. This paper presents a Generic Variable Pattern Selection (GYPS) algorithm. which introduces a pattern selection par...