Rate Control In Video Coding Research Articles

SUR-Driven Video Coding Rate Control for Jointly Optimizing Perceptual Quality and Buffer Control.

Rate control plays an important role in video coding and has attracted lots of attention from researchers. However, the problems of human visual experience and buffer stability still remain. For scenes with drastic motions, parts of distortions can be masked due to the limitation of the Human Visual System (HVS), while buffers tend to suffer more overflow and underflow cases from the fluctuating bits. In this paper, we propose a novel joint rate control scheme, which is composed of the proposed SUR-based perception modeling and the proposed SUR-based Perception-Buffer Rate Control (PBRC), for HEVC to maximize human visual perception quality while preventing the underflow and overflow of buffers. First of all, to effectively model human visual quality, we introduce the perception-related Satisfied-User-Ratio (SUR) metric into the rate control process. Secondly, a time-efficient video quality prediction method called Fast Visual Multimethod Assessment Fusion (VMAF) Quality Prediction (FVQP) is designed for the generation of SUR curves within an affordable computational complexity. Thirdly, a dual-objective optimization framework is established. By jointly conducting perception modeling and PBRC, we can flexibly adjust the optimization priority between human visual quality and buffer stability, and thus the quality of achieved reconstructed videos can be effectively improved because of the decrease in frame skipping. Experimental results demonstrate that the proposed joint rate control scheme improves the human visual experience when considering frame skipping and more effectively stabilizes buffer stability than existing methods.

Optimum Quality Control Algorithm for Versatile Video Coding

We propose a quality control method that replaces rate control in video coding and achieves quality control with the minimum bit rate. First, based on the rate–distortion model, we establish a Karush–Kuhn–Tucker equation considering the convergent properties of variational inequalities to solve the continuous convex problem. Second, combined with the rate–quality (R-Q) model, the proposed algorithm is implemented under versatile video coding (VVC) to obtain the optimal closed-form solution for the quantization parameters of a coding unit through the Lagrange multiplier method. Experiments reveal that our algorithm can achieve stable video coding quality while guaranteeing coding performance, achieving high quality control accuracy with constant quality.

Consistent Quality Oriented Rate Control in HEVC Via Balancing Intra and Inter Frame Coding

Consistent quality oriented rate control in video coding has attracted much more attention. However, the existing efforts only focus on decreasing variations between every two adjacent frames, but neglect coding trade-off problem between intra and inter frames. In this paper, we deal with it from a new perspective, where intra frame quantization parameter (IQP) and rate control are optimized for balanced coding. First, due to the importance of intra frames, a new framework is proposed for consistent quality oriented IQP prediction, and then we remove unqualified IQP candidates using the proposed penalty term. Second, we extensively evaluate possible features, and select target bits per pixel for all remaining frames, average and standard variance of frame QPs, where equivalent acquisition methods for QP features are given. Third, predicted IQPs are clipped effectively according to bandwidth and previous information for better bit rate accuracy. Compared with High Efficiency Video Coding (HEVC) reference baseline, experiments demonstrate that our method reduces quality fluctuation greatly by 37.2% on frame-level standard variance of peak-signal-noise-ratio (PSNR) and 45.1% on that of structural similarity (SSIM). Moreover, it also can have satisfactory results on Rate-Distortion (R-D) performance, bit accuracy and buffer control.

A novel rate control algorithm for low latency video coding base on mobile edge cloud computing

The current low-latency video coding rate control algorithm has similar video sequence structure, low rate control accuracy, long control time, etc., which cannot meet the expectations of modern workers. Based on this, this paper proposes a mobile edge cloud computing-based Low-latency video coding rate control algorithm, optimize the original control algorithm, improve its rate control accuracy, etc. By analyzing the relationship between mobile edge computing and cloud computing, combined with edge computing in the context of cloud computing, this paper proposes a mobile edge cloud computing method and designs the mobile edge cloud computing architecture. Low latency video sequences are obtained using mobile edge cloud computing, and a mobile edge cloud computing model is established to control the update rate parameters of delayed video files. According to the principle of rate control, based on joint rate–distortion theory and frame coding complexity calculation model, the low latency video coding rate control is realized. The experimental results show that the byte data volume of the low-latency video coding sequence of the proposed method is 5653 dB. The rate control accuracy can be as high as 99.64%, and the rate control time is 1.37 s. The proposed method has a high similarity of video sequence structure and high rate control accuracy and can effectively shorten the rate control time of low latency video coding.

Region-level bit allocation for rate control of 360-degree videos using cubemap projection

Featuring with more uniform sampling density in the sphere domain and less non-uniform geometric deformations in the planar domain, variants of cubemap projection (CMP) format enable the higher compression ratio in on-going 360-degree video coding standardization. Different from single-view videos, 360-degree CMP videos feature with content discontinuity combined with the abrupt change of motion vectors between some adjacent faces. However, there is few bit allocation scheme designed for rate control of video coding of CMP format. Thus, this paper proposes a region-level bit allocation scheme for rate control of interframe coding of CMP format. The proposed scheme consists of two parts. The first part is machine learning based high HEVC coding cost region detection for individual faces, where the feature descriptor of a CTU consists of the face based texture complexity, motion magnitude, motion density, and temporal coherence of motion vector. The second part is fitting function based region-level bit allocation. Different from previous work, bits are assigned to the high coding cost region and non-high coding cost region in individual faces of CMP format. Experimental results indicate that the proposed scheme achieves higher bitrate accuracy and larger BD-WS-PSNR compared with the original rate control scheme of the reference software of HEVC, HM16.16 with the 360Lib.

Uplink Resource Management for Multiuser OFDM Video Transmission Systems: Analysis and Algorithm Design

We consider a multiuser OFDM system in which users want to transmit videos via a base station. The base station knows the channel state information (CSI) as well as the rate distortion (RD) information of the video streams and tries to allocate power and spectrum resources to the users according to both physical layer CSI and application layer RD information. We derive and analyze a condition for the optimal resource allocation solution in a continuous frequency response setting. The optimality condition for this cross layer optimization scenario is similar to the equal slope condition for conventional video multiplexing resource allocation. Based on our analysis, we design an iterative subcarrier assignment and power allocation algorithm for an uplink system, and provide numerical performance analysis with different numbers of users. Comparing to systems with either only physical layer or only application layer information available at the base station, our results show that the user capacity and the video PSNR performance can be increased significantly by using cross layer design. Bit-level simulations which take into account the imperfection of the video coding rate control, the variation of RD curve fitting, as well as channel errors, are presented.

Modeling Rates and Distortions Based on a Mixture of Laplacian Distributions for Inter-Predicted Residues in Quadtree Coding of HEVC

Inprobability model based rate control of video coding, modeling of residual distribution is important in predicting precise distortions so as to determine appropriate quantization parameter values. For this, single probability model approaches have been popularly taken which may fail to model the underlying statistical characteristics of different residues from variable block-sized coding. In this letter, new rate and distortion models based on a mixture of multiple Laplacian distributions are presented for the transform coefficients of inter-predicted residues in quadtree coding. The proposed mixture model of multiple Laplacian distributions is tested for the High Efficiency Video Coding (HEVC) Test Model (HM) with quadtree-structured Coding Unit and Transform Unit. The experimental results show that the proposed model achieves more accurate results of rate and distortion estimation than the single probability models.

SSIM-Based Perceptual Rate Control for Video Coding

The quality of video is ultimately judged by human eye; however, mean squared error and the like that have been used as quality metrics are poorly correlated with human perception. Although the characteristics of human visual system have been incorporated into perceptual-based rate control, most existing schemes do not take rate-distortion optimization into consideration. In this paper, we use the structural similarity index as the quality metric for rate-distortion modeling and develop an optimum bit allocation and rate control scheme for video coding. This scheme achieves up to 25% bit-rate reduction over the JM reference software of H.264. Under the rate-distortion optimization framework, the proposed scheme can be easily integrated with the perceptual-based mode decision scheme. The overall bit-rate reduction may reach as high as 32% over the JM reference software.

PID-Based Bit Allocation Strategy for H.264/AVC Rate Control

To achieve the best visual quality under the minimum bit rate and the limited buffer size, the rate control allocates appropriate and smooth bits to each frame. This brief proposes an effective bit-allocation strategy for the H.264/Advanced Video Coding rate control. Based on the different characteristics of intraframes and interframes, we introduce the different bit-allocation approaches for them, respectively. A proportional-integer-derivative controller is adopted to minimize the deviation between the target buffer level and the current buffer fullness. To avoid buffer overflow or underflow, a novel setting method for the bit-allocation boundary is presented. Experimental results demonstrate that the proposed bit allocation strategy achieves smooth target bits while better buffer control and visual quality are derived.

A Reaction-Diffusion-Based Coding Rate Control Mechanism for Camera Sensor Networks

A wireless camera sensor network is useful for surveillance and monitoring for its visibility and easy deployment. However, it suffers from the limited capacity of wireless communication and a network is easily overflown with a considerable amount of video traffic. In this paper, we propose an autonomous video coding rate control mechanism where each camera sensor node can autonomously determine its coding rate in accordance with the location and velocity of target objects. For this purpose, we adopted a biological model, i.e., reaction-diffusion model, inspired by the similarity of biological spatial patterns and the spatial distribution of video coding rate. Through simulation and practical experiments, we verify the effectiveness of our proposal.

Recent advances in rate control for video coding

In this paper, we review the recent advances in rate control techniques for video coding. The rate control algorithms recommended in the video coding standards are briefly described and analyzed. Recent advances, such as new concepts in rate-distortion modelling and quality constrained control, are presented. With these techniques, the rate control performance can be improved. The paper not only summarizes these recent rate control techniques but also provides explicit directions for future rate control algorithm design.

On using game theory to optimize the rate control in video coding

This paper presents a game theory based technique for optimizing the bit rate control in video coding. Game theory, by virtue of its enormous potential for solving constrained optimization problems, has been effectively utilized in several branches of natural and social sciences. But this paper is the first attempt in using game theory for video compression. The objective is to optimize the perceptual quality while guaranteeing "fairness" in bit allocation among macroblocks (MBs). The proposed technique is a dual-level rate control algorithm: At the first level, the algorithm allocates the target bits to frames based on their coding complexity; a method to estimate the coding complexity of the remaining frames is proposed. At the second level, MBs of a frame play cooperative games such that each MB competes for a fair share of resources (bits) to optimize its quantization scale while considering the human visual system (HVS) perceptual property. We formulate the rate control problem by defining players, strategies and objective function. Since the whole frame is an entity perceived by viewers, MBs compete cooperatively under a global objective of achieving the best quality with the given bit constraint. The major advantage of the proposed approach is that the cooperative game leads to an optimal and fair bit allocation strategy based on the Nash bargaining solution. Another advantage is that it allows multi-objective optimization with multiple decision makers (e.g., MBs) in order to achieve accurate bit rate with good perceptual quality while maintaining a stable buffer level. Several extensions of the work are possible.

Visual sensitivity guided bit allocation for video coding

A video bit allocation technique adopting a visual distortion sensitivity model for better rate-visual distortion coding control is proposed in this paper. Instead of applying complicated semantic understanding, the proposed automatic distortion sensitivity analysis process analyzes both the motion and the texture structures in the video sequences in order to achieve better bit allocation for rate-constrained video coding. The proposed technique evaluates the perceptual distortion sensitivity on a macroblock basis, and allocates fewer bits to regions permitting large perceptual distortions for rate reduction. The proposed algorithm can be incorporated into existing video coding rate control schemes to achieve same visual quality at reduced bitrate. Experiments based on H.264 JM7.6 show that this technique achieves bit-rate saving of up to 40.61%. However, the conducted subjective viewing experiments show that there is no perceptual quality degradation. EDICS-1-CPRS, 3-QUAL.

A novel PDE-based rate-distortion model for rate control

This paper presents a novel rate-distortion (R-D) model for rate control of video coding. First, we investigate the well-known heat conduction equation (HCE) in the heat conduction process for a thin bar. HCE describes the dynamic distribution of temperature in a thin bar using a partial differential equation (PDE). Motivated by the heat conduction process in a thin bar, a new rate transmission equation (RTE) is proposed to describe the dynamic behaviors of the bit-rate fluctuation during video coding. Second, a particular solution of RTE is employed as our proposed R-D model, which consists of two variables, i.e., the distortion D and the source statistical character M. Based on our model, a corresponding rate-control scheme is proposed for MPEG coding. Finally, extensive experimental results are reported to show that, compared with the well-known MPEG-4 Q2 rate-control scheme, our proposed work achieves better buffer status, higher control accuracy, and stabler and more consistent picture quality.

Rate control for video coding using exchange of quantization noise and signal resolution

Rate control for video coding using exchange of quantization noise and signal resolution

The Impact of Rate Control Algorithms on System-Level VLSI Design

This paper presents an evaluation of rate control algorithms from a system-level VLSI design viewpoint. Rate control in video coding has a significant influence on the coded bit rate and image quality. Many rate control algorithms have been proposed mainly focusing on the optimal rate-distortion performance without considering their performance on the VLSI implementation. The purpose of this study is not to propose a hardware architecture for any specific algorithm but to study the algorithm impact on hardware design. Based on our finding, a system designer should choose an algorithm not only good in rate control performance but also good in hardware implementation. When implementing and comparing a few rate control algorithms using a generic processor structure, we found that, in addition to the ordinary computational complexity, the internal buffer size is also very critical in VLSI realization. Several picture sequences have been tested including one sequence constructed specifically to simulate a difficult case for rate control. In this paper, three different types of popular rate control algorithms have been analyzed based on their picture quality, the internal buffer size, and the hardware cost. The methodology and results presented here provide useful guidelines for selecting an appropriate rate control algorithm for system-level VLSI designers.