Improved Rate Control Algorithm Research Articles

Improved Rate Control Algorithm Based on R- Model in High Efficiency Video Coding

In order to improve the accuracy of rate control for High Efficiency Video Coding, the paper proposed an improved rate control algorithm based on R- model. First of all, it exploits G and MAD weighting to represent the complexity of the LCU layer image. Afterwards, it utilizes the feedback information of the encoded units to further adjust the quantization parameters. Eventually, the model parameters are updated by using video coding distortion and Newton method. Experimental results illustrate that the average Bit-error of the improved algorithm reduces by 0.055%, and the average luminance peak signal to noise ratio increases by 0.07dB compared with rate control algorithm for the current HEVC.

Improved macroblock level rate control for the spatially scalable extension of H.264/AVC

An improved rate control algorithm, designed for scalable video coders incorporating interlayer prediction, is proposed. Firstly, a Rate Distortion (RD) model for interlayer prediction involving the spatial enhancement layers is devised. An optimised Mean Absolute Difference (MAD) prediction model for the spatial enhancement layers that considers both the MAD from the spatial base layer in the same frame and the MAD from the corresponding macroblock in previous frames is also proposed. Simulation results show that the resulting algorithm produces accurate rate control with an average bit rate error of less than 0.26%. Compared with the JVT-W043 default rate control algorithm of the JSVM, the proposed algorithm improves the average PSNR by up to 0.53dB or reduces the bit rate by an average of 10.95%. Furthermore, the proposed algorithm can be combined with the existing rate control scheme for H.264/AVC, resulting in further improvements.

A Fast and Efficient Adaptive Threshold Rate Control Scheme for Remote Sensing Images

The JPEG2000 image compression standard is ideal for processing remote sensing images. However, its algorithm is complex and it requires large amounts of memory, making it difficult to adapt to the limited transmission and storage resources necessary for remote sensing images. In the present study, an improved rate control algorithm for remote sensing images is proposed. The required coded blocks are sorted downward according to their numbers of bit planes prior to entropy coding. An adaptive threshold computed from the combination of the minimum number of bit planes, along with the minimum rate-distortion slope and the compression ratio, is used to truncate passes of each code block during Tier-1 encoding. This routine avoids the encoding of all code passes and improves the coding efficiency. The simulation results show that the computational cost and working buffer memory size of the proposed algorithm reach only 18.13 and 7.81%, respectively, of the same parameters in the postcompression rate distortion algorithm, while the peak signal-to-noise ratio across the images remains almost the same. The proposed algorithm not only greatly reduces the code complexity and buffer requirements but also maintains the image quality.

Joint Rate Control Algorithm for Low-Delay MPEG-4 Object-Based Video Encoding

This paper proposes an improved rate control algorithm for jointly encoding multiple arbitrarily shaped video objects in the context of low-delay MPEG-4 compliant video coding. The algorithm provides adequate mechanisms for dealing with deviations between the ideal and the actual behavior of video scene encoders, notably: 1) compensation mechanisms (e.g., rate control decisions) that are able to track these deviations and compensate them to allow a stable and efficient operation of the encoder, and 2) adaptation mechanisms (e.g., estimation of model parameters) that are able to instantaneously represent the actual behavior of the encoder and its rate controller. The proposed solution efficiently allocates the available resources, i.e., target bit rate and bitstream buffer space, aiming at maximizing the average scene quality and minimizing quality fluctuations along time and among the various video objects. The results show that this solution outperforms the usual reference solutions, notably those specified in the rate control informative annex of the MPEG-4 visual standard.

Rate control algorithm based on standard H.264

During the video communication process,an improved rate control algorithm was developed based on H.264 video coding standard in order to make the output data stream better adapted to different channels.Contrary to the MAD prediction of the basic unit only considering the relationship of the time in the coding standard,a new prediction method was introduced combining time prediction and space prediction.Compared with coding standard,the experimental results illustrate that the new algorithm can control rate more precisely and increase the peak signal noise ratio of the output video stream effectively.It proves that the new algorithm can make the output data stream of the encoder more stable.

An improved rate control algorithm based on a novel shot detection scheme for the H.264/AVC standard

H.264/AVC standard uses a variety of advanced signal processing/video coding techniques for broadcast quality video on half the bit rate required in MPEG-2. Despite being advanced, the current rate control algorithm of the standard does not exploit the fact that typical video sequences are composed of different shots. This paper argues that shot information can help us choose the size of the group of pictures (GOPs) more accurately, thus improving the performance of the rate control algorithm. We initially propose a novel MPEG-7 descriptor driven shot detection method with low computational cost for H.264/AVC. Then we exploit it to determine the initial quantization parameters for each shot based on modelling. These two steps can help us reduce the bit rate and PSNR fluctuation when video sequences have multiple shots. Our proposed scheme outperforms the rate control of the H.264/AVC significantly in terms of reducing the average bit rate fluctuation (variance) by 12.78–99.99% and the average PSNR fluctuation (variance) by 1.4–71% between shots. Experimental results also demonstrate that we can achieve similar or even better rate distortion (R-D) performance than the standard rate control algorithm. Our scheme is also applicable to computationally and memory restricted devices since it needs maximum two frames buffer space for MPEG-7 descriptor calculation, while the average amount of extra processing is only about 5.5% of the total CPU cycles.