Norbert Oertel

Advanced Lagrange Multiplier Selection for Hybrid Video Coding

The Lagrangian multiplier based rate-distortion optimization has been proved to be an effective way in hybrid video coding. In this paper, an advanced Lagrange multiplier selection method is presented. Based on Laplace distribution, the variance of transformed residuals is introduced into the rate and distortion models. Moreover, inspired by the p-domain method, the percentage of non-zeros among quantized residuals is also considered to refine the rate model. Thanks to the more accurate models, the proposed method is able to adaptively optimize the encoding process for videos with different properties. It outperforms the algorithm used in the reference software of H.264/AVC. According to the simulation, a gain up to 1.1 dB was achieved.

Gradient Intra Prediction for Coding of Computer Animated Videos

The increasing interest in computer animations initiated the need of efficient coding for such applications. This paper proposes two gradient based approaches to improve the efficiency of Intra Prediction. Taking advantage of a special property of computer animations, namely the gradient distribution of intensity on object surfaces, the devised methods provided a better performance over H.264/AVC. According to the simulations, up to 0.3 dB gain in PSNR has been achieved

Adaptive Lagrange Multiplier Selection for Intra-Frame Video Coding

The Lagrangian technique proves to be an effective way in rate-distortion optimization for hybrid video coding. In this paper, an new Lagrange multiplier selection method for intra-frame coding is presented. Based on Laplacian distribution, the variance of transformed residual coefficients is introduced into the rate and distortion model, so that the proposed method is able to adaptively optimize the encoding process for different types of videos. It outperforms the algorithm used in the reference software of H.264/AVC, especially for computer animations and videos with small movements. According to the simulations, a gain up to 0.3 dB was achieved.