H.264/AVC INTER-FRAME RATE-DISTORTION DEPENDENCY ANALYSIS BASED ON INDEPENDENT REGIME-SWITCHING AR MODELS

The control of the encoding rate and the video quality is a challenging task. This control requires efficient rate and distortion (R-D) models that describe the best the real encoder behavior. To that end, different Rate-Distortion (R-D) models was proposed in the literature. Efficient R-D models should take into account inter-frame dependencies involving the previous and current quantization parameter (QP). In this paper we propose an efficient dependent R-D model for video coder described by an independent switching-regime Autoregressive (IRS-AR). The R-D characteristics are evaluated using a simple compound model for DC and AC coefficients. Experimental results show that the examined set of curves corresponding to IRS-AR model with the estimated parameters represent accurately represent the distortion dependency between frames. For the rate, additional adjustments have to be performed to account for the cost of motion vectors and signalization. Index Terms-- Rate distortion theory, Autoregressive processes, Video codecs 1. INTRODUCTION Among the various problems raised by the efficient delivery of realtime video contents via a wireless channel, the control of the encoding rate is a challenging task. This control has to cope with a time-varying quality of the channel, which results in variations in the channel capacity, and with changing complexity of the scenes to be encoded. Buffers are usually present at several places of the communication chain, e.g., at the output of the source coder, within the base station, at the receiver.