Video transcoding is an efficient way for rate adaptation and format conversion in various networked video applications. Several transcoder architectures have been proposed to achieve fast processing. Recently, thanks to its relatively low complexity, the DCT-domain transcoding schemes have become very attractive. In this paper, we investigate efficient architectures for video downscaling in th...

The vertical or horizontal edges don’t dominate in some frames of video sequence, so the conventional discrete cosine transform (DCT) may not be the best choice for those frames. Directional DCT framework behaves better than conventional DCT in coding performance for images where directional edges dominate. In addition, the all phase biorthogonal transform (APBT), which is used in image compres...

In this paper, the Bit Error Rate (BER), performance of conventional Discrete Fourier Transform (FFT) OFDM system is compared with Nonconventional Discrete Cosine Transform (DCT)OFDM system in AWGN and Rayleigh fading environment. Performance has been given with conventional mapping schemes like BPSK, QPSK and nonconventional mapping schemes like DQPSK and π/4 DQPSK. Simulation results show tha...

This paper proposes an energy-efficient hardware acceleration architecture for the variable N-point 1D Discrete Cosine Transform (DCT) that can be leveraged if implementing MPEG-4’s Shape Adaptive DCT (SA-DCT) tool. The SA-DCT algorithm was originally formulated in response to the MPEG-4 requirement for object based texture coding, and is one of the most computationally demanding blocks in an M...

In the framework of the ongoing MPEG–4 standardization phase of ISO/IEC Sikora and Makai suggested a shape–adaptive DCT algorithm (SA–DCT) for efficient and low–complexity coding of arbitrarily shaped video objects. Referring to this algorithmic approach, the objective of the underlying contribution is to emphasize a performance limitation of conventional SA–DCT definition and to propose an ext...

We show that an efficient quantizer originally developed for wavelet compression can be applied to DCT coding with excellent results. We have implemented a system for block-based, embedded, progressive, DCT image compression which makes use of the embedded zerotree wavelet (EZW) algorithm of Shapiro. The image is partitioned into a number of distinct square blocks and the DCT applied to each of...

The Discrete Cosine Transform (DCT) is significantly of interest in the area of image compression according to its high compaction energy. It has become the core of many international standards such as JPEG, H.26x and the MPEG family [1-3]. In both software and hardware implementations, there appear many fast algorithms to speed up the computation of DCT. A 2-D DCT can be easily computed by rec...

The discrete cosine transform (DCT) is widely regarded as a key operation in digital signal processing [15,51]. In fact, the Karhunen-Loève transform (KLT) is the asymptotic equivalent of the DCT, being the former an optimal transform in terms of decorrelation and energy compaction properties [1,15,18,23,37,51]. When high correlated first-order Markov signals are considered [15, 51]—such as nat...

This paper presents an efficient approach for multiplierless implementation for eight-point DCT approximation, which based on coordinate rotation digital computer (CORDIC) algorithm. The main design objective is to make critical path of corresponding circuits shorter and reduce the combinational delay of proposed scheme. 1. INTRODUCTION It is well know that the discrete cosine transform (DCT) h...

In this paper we present a reconfigurable 16 Approximation of discrete cosine transform (DCT) using 8 point additions with less number of calculations. Most of the existing algorithms for approximation of the DCT target only the DCT of small transform lengths, and some of them are non-orthogonal. This paper presents a generalized recursive algorithm to obtain orthogonal approximation of DCT whe...