Cauchy-Density-Based Basic Unit Layer Rate Controller for H.264/AVC

Abstract

Abstract-The rate control problem has been extensively studied in parallel to the development of the different video coding standards. The bit allocation via Cauchy-density-based ratedistortion (R-D) modeling of the discrete cosine transform (DCT) coefficients has proved to be one of the most accurate solution at picture level. Nevertheless, in some specific applications operating in real-time low-delay environments, a basic unit (BU) layer is recommended in order to provide a good trade-off between picture quality and delay control. In this paper, a novel BU bit allocation for H.264/AVC is proposed based on a simplified Cauchy probability density function (PDF) source modeling. The experimental results are twofold: 1) the proposed rate control algorithm (RCA) achieves an average PSNR improvement of 0.28 dB respect to a well known BU layer RCA, while maintaining a similar buffer occupancy evolution; and 2) It achieves to notably reduce the buffer occupancy fluctuations respect to a well known picture layer RCA, while maintaining similar quality levels.

A low-complexity parallel-friendly rate control algorithm for ultra-low delay high definition video coding

“…Table 1 reports the BD-rate performance of both RCAs referred to multi-slice CQP coding for the two types of scalability (notice that the results for BS-QS and BS-SS do match, since the same number of slices was employed). As can be observed, the reference RCA achieves better BD-rate performance, as expected, since picture-level RCAs generally provides better quality than MB-level RCAs for a given target bit rate [6]. Table 2 illustrates the coding performance in terms of target bit rate adjustment, by measuring the bit rate error respect to CQP coding, and buffer control, by measuring the average/maximum percentages in which overflows (#O) or underflows (#U) occurred in one coding.…”

“…For a proper selection of the QP value, the RCA has to incorporate the combination of video complexity and target bit rate as well as the hypothetical reference decoder (HRD) constraints [5]. Several RCAs suitable for video conferencing, such as those summarized in [6] and Fig. 1.…”

“…[7], have been proposed. However, neither of them is designed for a parallel framework, which is required to achieve real-time coding in HD sequences, unless a picture-level QP decision strategy is conducted at the expense of higher instantaneous bit rate variations [6].…”

In-Layer Multibuffer Framework for Rate-Controlled Scalable Video Coding

“…In single-layer video coding, several R-D functions have been proposed: logarithmic [13]- [15], linear [16], [17], quadratic [18]- [22] (in particular, Chen et al [21] proposed separate R-D models for luminance and chrominance DCT coefficients, whilst Kwon et al [22] proposed separate rate models for source and header bits), ρ-domain [23] and exponential [24], [25]. Although the RC algorithm is not a normative part of video coding standards, it usually forms part of their reference implementations, such as the Test Model Version 5 for MPEG-2 [16], the Verification Model Version 8 for MPEG-4 [18], the Test Model Near-Term 8 for H.263 [14], and the Joint Model for H.264/AVC [19].…”

RBF-Based QP Estimation Model for VBR Control in H.264/SVC

“…For instance, assuming a Gaussian probability density function (PDF) for DCT coefficients, a logarithmic R-D function can be inferred [8]. Alternatively, assuming a Cauchy PDF, a simple exponential R-D model is derived [9], [10]. On the other hand, using a Laplacian PDF, different linear [11], quadratic [5] or ρ-domain-based [12] R-D models have been proposed.…”