The Dirac codec is a new prototype video coding algorithm from BBC R&D based on wavelet technology. Compression-wise the algorithm is broadly competitive with the state-of-the-art video codecs but computational-wise the execution time is currently poor. One of the largest bottlenecks is the arithmetic coder. Hence we took this part under investigation and replaced it with a faster variant, the ...

This paper presents our study on the feasibility and effectiveness of using the MELP (Mixed Excitation Linear Prediction) model for coding wideband (7KHz) speech signals at a transmission bit rate of 8kbps. In order to achieve a reasonably good subjective quality for the decoded speech while maintaining a low operating bit rate at the same time, modifications to the pitch estimation, LP analysi...

Entropy coding provides for the lossless compression of data symbols and is a critical component in signal compression algorithms. In the case where there is statistical dependence between the symbols produced by the source, the performance of an entropy coder can be significantly improved by having the coder dynamically adapt to the current "context". This thesis considers the specific case of...

JPEG2000 is a one of the popular image compression standard. The vital part of this standard JPEG2000 is Embedded Block Boding with Optimal Truncation (EBCOT). This block conserves major part of the processing time for performing compression operation. The EBCOT block consists of two components called bit-plane coder and MQ coder. The use of Field Programmable Gate Arrays (FPGAs) provides speci...

A new 1200 bps speech coder designed with a tree searched multistage matrix quantization scheme is proposed. To improve speech quality and reduce the average bit rate, we have developed a new residual multistage matrix quantization method with the joint design technique. The new joint design algorithm reduces the codebook training complexity. Other new techniques for improving the performance i...

| In this paper, a novel and simple embedded wavelet coder, called a multi-threshold embedded zerotree wavelet coder, is proposed. The well-known embedded ze-rotree wavelet (EZW) coder uses the successive approximation quantization (SAQ) process and zerotree structures of wavelet coeecients. The EZW coder scans iteratively whole wavelet coeecients during the SAQ process, which decreases the cod...