A low delay and low complexity speech coder based on Multimode Tree Coding is proposed. In our Multimode Tree Coder, a simple mode classification method along with frame energy are used to classify the input speech frames into five different modes. Each mode is coded at a suitable bit-rate using a Tree coder with computationally efficient perceptual error pre-weighting and post-weighting filter...

This paper proposes a flexible CELP speech coder with bitrate and bandwidth scalabilities for multimedia applications. The coder is based on multi-pulse-based CELP coding and consists of a bitrate scalable base-band coder and a bandwidth extension tool. The bitrate scalable base-band CELP coder employs multi-stage excitation coding based on an embedded-coding approach. The multipulse excitation...

The multiple description transform coder is introduced for sources with memory and an asymptotic analysis is presented for the squared error distortion. For stationary Gaussian sources, the optimal transform and the optimal bit allocation for the multiple description coder are identical to those for the single description coder.

A transform based sub-band coder which uses vector quantization is described. The coder is capable of producing very good quality speech at 16 Kb/s and good quality speech at 9.6 Kb/s. The delay and complexity of this coder are substantially reduced when compared with conventional filter bank sub-band coders.

This paper presents a modified JPEG coder that is applied to the compression of mixed documents (containing text, natural images, and graphics) for printing purposes. The modified JPEG coder proposed in this paper takes advantage of the distinct perceptually significant regions in these documents to achieve higher perceptual quality than the standard JPEG coder. The region-adaptivity is perform...

* Mr. S. Maćkowiak is Fellow of the Foundation for Polish Science. Abstract The paper deals with a three-layer video coder based on spatio-temporal scalability and data partitioning. The proposed coder consists of two parts: a low-resolution coder and full-resolution coder. The first part encodes pictures with reduced spatial and temporal resolution. The full-resolution encoder exploits interpo...

In this paper, we propose a hybrid video coder using the wavelet packet transform and motion compensation. To reduce the computational complexity of the wavelet packet decomposition, a novel criterion based on the rate-distortion function is proposed. After the wavelet packet transform, the successive quantization scheme and the adaptive arithmetic coder are applied for lossy wavelet coe cient ...

This paper describes a fast, low-complexity, entropy efficient video coder for wavelet pyramids. This coder approaches the entropy-limited coding rate of video wavelet pyramids, is fast in both hardware and software implementations, and has low complexity (no multiplies) for use in ASICs. It consists of a modified Z-coder used to code the zero/non-zero significance function and Huffman coding f...

this paper presents a full duplex, real time implementation of itu-t g.723.1 [7,8] speech coder using the tms320c5402 dsp chip which is based on a 16 bit fixed-point architecture. an optimization method is proposed in order to reduce the total necessary cycle time consumed in real-time implementation. the multi-pulse maximum likelihood quantization (mp-mlq) excitation search block which is the ...

In this paper, we introduce a new approach to solve encoding method switching problems in a parametric/waveformmatching hybrid coder. This method only requires modification of the waveform-matching coder’s target signal. For this purpose, we introduce a new pitch-synchronous cycle length modification method using the constant pitch transformation (CPT) and a frequency domain zero-phase equaliza...