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...

We propose an optimal buffered compression algorithm for shape coding as defined in the forthcoming MPEG-4 international standard. The MPEG-4 shape coding scheme consists of two steps: first, distortion is introduced by down and up scaling; then, context-based arithmetic encoding is applied. Since arithmetic coding is "lossless," the down up scaling step is considered as a virtual quantizer. We...

In this paper, we propose a QP (Quantization Parameter) selection method for H.264 based MVC (Multi-view Video Coding). The proposed method adaptively calculates QP for B frames in anchor (BANC frames). This method utilizes rate-distortion costs of the two frames which are referred by BANC frames. Using these costs, we estimate the correlation between the reference frames. The first reference f...

In this paper, it is considered the image compression scheme, in which a part of coded data extracted in the coding process is hidden into the other parts of coded data of own image, especially into the block address data of the best matching block within restricted blocks. The proposed scheme is able to be used in a fractal image coding in which the best matching domain block is searched, in a...

Image Data compression using vector quantization (VQ) has received a lot of attention in the recent years because of its optimality in rate distortion and adaptability. A fundamental goal of data compression is to reduce the bit rate for transmission or data storage while maintaining an acceptable fidelity or image quality. The combination of subband coding and vector quantization can provide a...

For coding of quantized transform coefficients, a coded block pattern (CBP) is a key syntax element to represent the existence of coefficients in a macroblock efficiently. In H.264/AVC, the CBP is coded by using a fixed variable length coding table, called Exp-Golomb codes. However, since the CBP is highly affected by the change of quantization parameter (QP), in this paper, we show the CBP dis...

In this paper, a very low bit rate image compression scheme is proposed. This scheme is a hybrid method that combines the good energy-compaction property of DCT with the high compression ratio of VQ-based coding. We start by transforming image block from spatial domain to frequency domain using DCT. In order to increase the compression ratio while preserving decent reconstructed image quality, ...

In this paper, we present a wavelet packet image coding algorithm based on quadtree classification and UTCQ. It is composed of four parts: (1) wavelet packet decomposition and best basis selection based on a new cost function, (2) a quadtree classification procedure, used to classify the wavelet packet coefficients into two sets: a significant one and an insignificant one, (3) the universal tre...

The quality of speech signal over a VoIP system is degraded by various network layer problems which include jamming, jitter, packet loss. Different types of noises also degrade the quality of speech signal such as external noise and quantization noise. This paper improves the quality of VoIP speech signal affected by these noises and network layer problems. The quality of degraded VoIP speech s...

One of the drawbacks of the Discrete Cosine Transform (DCT) is visible block boundaries due to coarse quantization of the coefficients. In this paper, an algorithm for the reduction of blocking artifacts is presented. The proposed method allows to produce higher quality reconstructed images by adaptively filtering the video signal according to the noise visibility. A visual model is therefore d...