Bojun Meng

Efficient intra-prediction algorithm in H.264

In the upcoming H.264, intra-prediction with block sizes of 4/spl times/4 and 16x16 is used to compress I-frame. However, there are 9 or 4 candidate modes for the 4x4 or 16x16 intra-prediction. The full search algorithm to choose the modes is computationally expensive. In this paper, we suggest an efficient intra-prediction (EIP) algorithm based on early termination, selective computation of highly probable modes, and partial computation of the cost function. The proposed EIP reduces the complexity considerably while maintaining similar PSNR and bit rate.

Fast intra-prediction mode selection for 4A blocks in H.264

In the upcoming H.264 advanced video coding standard, intra-prediction for each 4/spl times/4 block is used to compress I-frames. However, the full search algorithm to choose one of the 9 prediction modes is computationally expensive. We propose a fast intra-prediction mode selection (FIPMS) method based on partial computation of the cost function, early termination and selective computation of highly probable modes. The proposed FIPMS can reduce the complexity considerably while maintaining similar PSNR and bit rate.

Perceptual rate control for low-delay video communications

The existing rate control schemes in the literature evaluate their video quality performance in terms of traditional PSNR. Actually, this evaluation may not be good because this measurement is not the same as that judged by human. This work defines a perceptual quality measure based on the human vision system. The modified rate control includes the perceptual consideration. The results show that the perceptual rate control achieves average perceptual quality gain over TMN8.

Efficient intra-prediction mode selection for 4/spl times/4 blocks in H.264

In the upcoming H.264, intra-prediction for 4/spl times/4 and 16/spl times/16 blocks is used to compress I-frame. However, we need to choose one of the 9 prediction modes for each 4/spl times/4 block. The full search (FS) algorithm to select the mode is computationally expensive. In this paper, an efficient intra-prediction mode selection (EIPMS) method is proposed based on partial computation of the cost function, selective computation of highly probable modes, early termination, and variable threshold setting. The proposed EIPMS can reduce the complexity considerably while maintaining similar PSNR and bit rate.

Novel H.26X optimal rate control for low-delay communications

The existing rate control schemes in the literature calculates the quantization parameters of macro-blocks (MB) based on the quadratic/log rate models. Actually, this model may not be good because this model does not estimate well at some particular bit rates. This work investigates the relationships of bit rate and distortion with the MB quantization step size and standard deviation of MB prediction errors. We find that the linear rate and linear distortion models are established. Then we present the proposed rate control schemes based on these models. The proposed algorithm introduces a low quantization overhead, low computation complexity to calculate the optimal quantization step size, independence of the distortion factors and low memory usage compared with TMN8 rate control. The experimental results suggests that our scheme can achieve PSNR gain over TMN8.