MPEG-7 Descriptors Based Shot Detection and Adaptive Initial Quantization Parameter Estimation for the H.264/AVC

Abstract

Currently no information about different shots is used in the H.264/AVC video coding standard. This kind of information can help us choose more optimally the size of the Group of Pictures (GOPs) used for encoding of video content. In this paper, we initially propose an MPEG-7 descriptor based shot detection technique with low computational cost for H.264/AVC. Then we propose an adaptive initial quantization parameter (QP) estimation method for each shot based on modeling, training according to the content of video sequences and the shot detection method of our previous step. This two step architecture can help us reduce the bit rate and PSNR fluctuation when video sequences have multiple shots. Our proposed scheme outperforms the rate control of the H.264/AVC significantly in terms of reducing the average bit rate fluctuation (variance) by 8.6%-99% and the average PSNR fluctuation (variance) by 5%-99% between shots. Experimental results also demonstrate that the proposed algorithm can achieve similar or even better Rate Distortion (R-D) performance than standard Rate Control algorithms. It is also applicable in computationally and memory restricted devices since it needs maximum 2 frames buffer space for MPEG-7 descriptor calculation, while the average amount of extra processing is only about 5.8% of the total CPU cycles.