Mengyao Zhu

Streaming audio packet loss concealment based on sinusoidal frequency estimation in MDCT domain

A Packet Loss Concealment (PLC) method is proposed for audio streaming represented in the Modified Discrete Cosine Transform (MDCT) domain. MDCT is the dominant transform of perceptual audio coding and widely used in consumer electronics. The MDCT coefficients of a lost frame are reconstructed by our PLC method, which is based on audio sinusoidal model in MDCT domain. The sinusoid-like coefficients could be predicted by sinusoidal frequency estimation, and further optimization of computation is achieved by using sign property of sinusoids. In order to compare with other approaches, both subjective and objective evaluation tests are conducted. The experimental results show that the computational complexity and memory requirement of our approach are greatly reduced, while good quality is maintained.

A new fragile audio watermarking scheme

This paper proposes a novel fragile watermarking scheme for audio content authentication. The chaotic mapping based watermark information is embedded in the principal component of the detail wavelet coefficients of the host audio based on the instantaneous mixing model of independent component analysis system. The watermark can be extracted with Fast ICA technique, blindly. Experimental results demonstrate that the proposed scheme achieves excellent transparency, good fragility, and accurate tampering detection.

A more efficient triangle rasterization algorithm implemented in FPGA

3D graphics hardware acceleration has become more and more important in mobile devices. In the paper, we review some triangle rasterization algorithm previously. On that basis, we propose a novel triangle rasterization algorithm - midpoint traversal, which reduce the number of traversal points and improve the efficiency of graphic acceleration. At last, we use FPGA to implement the algorithm, drawing a conclusion: in the equality resource, compared with others triangle rasterization algorithm based edge function, the midpoint traversal can improve the efficiency.

A analysis of mobile graphics pipeline with real-time performance

With the widely development of consumer electronics, 3D graphics have been in high demand and it has also become a very important module in embedded systems. Recent years more and more attentions have been paid on 3D graphics rendering. As we know it is very difficult to achieve real-time interactive request in the complex 3D graphics rendering on a signal CPU, therefore a dedicated graphics processor is need to enhance the rendering speed. But in embedded system, source is limited and power is supplied by battery, so that the 3D graphic processing for mobile environment can not employ the same algorithm or architecture as in the pc environment. In this paper, we review a full 3D graphics pipeline and discuss optimizations of graphics architecture have been made to overcome the shortcomings in mobile environment.

A novel triangle rasterization algorithm based on edge function

With the widely used of mobile devices, such as cellular phone, personal digital assistant (PDA), mobile navigator, personal multimedia player (PMP), 3D graphics are becoming key to mobile device experience. 3D graphics hardware acceleration has become more and more important in mobile devices. In the paper, we review some triangle rasterization algorithm previously. On that basis, we propose a novel triangle rasterization algorithm - midpoint traversal, which reduces the number of traversal points and improves the efficiency of graphic acceleration. At last, we use FPGA to implement the algorithm, drawing a conclusion: in the equality resource, the midpoint traversal can improve the efficiency.

Packet Loss Concealment for compressed audio stream using sinusoidal frequency estimation

In this paper we propose a Packet Loss Concealment (PLC) method for audio compressed in the Modified Discrete Cosine Transform (MDCT) domain. Based on sinusoidal and noise model in MDCT domain, a novel sinusoidal frequency estimation method is adopted to reconstruct the sign of MDCT coefficients in a lost frame. Further optimization is achieved by investigation of the cosine property. Both subjective and objective assessments are examined, and the results show that our proposed algorithm achieves almost first-class quality, while a small amount of calculation and memory are consumed.

Fast convolution for binaural rendering based on HRTF spectrum

This paper presents an efficient convolution technique in Modified Discrete Cosine Transform (MDCT) domain. It can be used to accomplish Head-Related Transform Function (HRTF) based binaural rendering. The MDCT and HRTF are firstly represented in a polyphase filter structure and further derived to a z-transform matrix representation. Based on the property of similarity between diagonal entries of filtering matrix and spectrum of HRTF, we presented a Dynamic Adjacent Elements Optimization (DAEO) for fast convolution of HRTF in the MDCT domain. Experimental results show that our algorithm greatly reduces the computational complexity, and maintains equal quality. The complexity analysis of virtual surround processing methods indicates that our filtering algorithm of HRTF consume minimal calculation, which is particularly suitable for audio compressed in MDCT format.

Room impulse response simulation based on equal-area ray tracing

Sound rendering are frequently used to enhance the sense of immersion in virtual environments and multimedia applications. For this purpose, this paper proposes a ray tracing method based on equal-area distribution to simulate room impulse response (RIR). It is efficient and accurate to get the direction of arrival of the direct sound and early reflections. An equal-area distribution was adopted in the process of the sound source emitting. In order to optimize the sound source directivity, the direct sound and early reflections of RIR were mainly concerned. In our experiment, the RIR produced by ROOMSIM was set a reference. In addition, Monte Carlo method of equal-angle distribution was also presented as a comparison. Our proposed equal-area ray tracing (EART) can get a better result for early reflection and later reverberation.

On objective assessment of audio quality — A review

Measurement of audio quality is of fundamental importance for numerous speech and audio processing applications, where the goal of quality assessment algorithms is to evaluate the quality in agreement with humans subjective feelings of audio quality. This paper includes a brief summary of the development of intrusive and non-intrusive audio quality assessment algorithms and outlines recent advancements, especially some new topics to be investigated presently. Moreover, according to the existing problems in this field, discussion of the future trend and challenges is also given.

High efficient logarithm convertor for graphics physics simulation

In this paper, we propose an efficient algorithm to piecewise linear approximation of logarithm for the possible application to graphics physics simulation. Compared to the traditional approximation of logarithm methods, our algorithm produce a maximum relative error flatten distribution in all intervals, the maximum relative error can be set according to our difference accuracy needs. Simulations of our methods have been conducted in Matlab to verify correctness. Besides, we further present the hardware implement. Comparison simulation showed that our algorithm is superior to state-of-art logarithm conversion for stimulation accuracy.