Optimal bit allocation scheme for rate-distortion control of video encoding in real-time video streaming system

Abstract

a zero quantization parameter as an indicator for the decision of the zero block encoding

and iii) a CTU-level bit allocation scheme that exploits i) and ii). Experimental results are very promising compared to the previous methods.

In real-time video streaming applications based on battery-powered camera systems, it is crucial to capture and transmit critical information satisfying the memory capacity and channel bandwidth requirement. However, the increase of data rate in ultra high denition video contents aggravates the memory capacity and the channel bandwidth problem. Therefore, one of the crucial issues is to minimize the bit-rate of the video encoding so as to satisfy the system constraints. Most of the rate control schemes has the large frame-to-frame distortion variation at the cost of regulating the bit-rate, thereby it mostly leads to poor perceptual video quality according to the human visual system. In this dissertation, I present two single-pass bit allocation schemes: i) frame-level bit allocation to minimize the frame-to-frame distortion variation satisfying the bit-rate constraint, and ii) coding tree unit (CTU)-level bit allocation scheme to minimize the encoding bit-rate while satisfying keeping the perceptual video quality. In Chapter 1, I propose a single-pass content-aware video encoding scheme to achieve a consistent video quality while satisfying the bit-rate constraints. To achieve the objective I developed i) scene descriptor based on the discrete cosine transformation (DCT) coefficients obtained from the video encoder, ii) a parameterized analytic distortion model for video encoding using the scene descriptor, iii) scene change detection based on the encoded macroblock (MB) mode ratio, and iv) a single-pass consistent video quality control scheme which exploits i), ii), and iii). In chapter 2, I propose a CTU-level bit allocation scheme to achieve the minimization of encoding bit-rate considering the perceptual video quality of the reconstructed frames after the video encoding process. To achieve the objective, I developed: i) an analytical model for the structure similarity (SSIM) index estimation based on the statistics of the input frame only