R-lambda rate control scheme is recommended in the High Efficiency Video coding (HEVC) standard, which shows high accuracy of bit rate control but lower rate distortion performance. In order to minimize the distortion...
详细信息
ISBN:
(纸本)9781509036493
R-lambda rate control scheme is recommended in the High Efficiency Video coding (HEVC) standard, which shows high accuracy of bit rate control but lower rate distortion performance. In order to minimize the distortion subject to a target bit rate, a lambda domain frame-level rate control scheme for low delay coding of HEVC was proposed. Firstly, an improved parameter updating method is presented for the frame level rate distortion model, which full uses the information of encoded frames in the previous group of pictures (GOP). Then, an adaptive dynamic frame level bit allocation scheme is proposed by employing global rate distortion optimization theory. Finally, to further improve the coding efficiency, the bits allocation adjustment is made for the first several GOPs in video sequence according to the rate distortion dependency. The experimental results show that the proposed method can greatly improve the rate distortion performance under the condition of high accuracy of bit rate control.
We consider the transmission of packets across a lossy end-to-end network path so as to achieve low in-order delivery delay. This can be formulated as a decision problem, namely deciding whether the next packet to sen...
详细信息
We consider the transmission of packets across a lossy end-to-end network path so as to achieve low in-order delivery delay. This can be formulated as a decision problem, namely deciding whether the next packet to send should be an information packet or a coded packet. Importantly, this decision is made based on delayed feedback from the receiver. While an exact solution to this decision problem is challenging, we exploit ideas from queueing theory to derive scheduling policies based on prediction of a receiver queue length that, while suboptimal, can be efficiently implemented and offer substantially better performance than state of the art approaches. We obtain a number of useful analytic bounds that help characterise design trade-offs and our analysis highlights that the use of prediction plays a key role in achieving good performance in the presence of significant feedback delay. Our approach readily generalises to networks of paths and we illustrate this by application to multipath trans port scheduler design.
We consider the problem of joint recovery of a bivariate Gaussian source and of interference over the two-user Gaussian degraded broadcast channel in the presence of common interference. The interference, that is avai...
详细信息
We consider the problem of joint recovery of a bivariate Gaussian source and of interference over the two-user Gaussian degraded broadcast channel in the presence of common interference. The interference, that is available non-causally at the encoder, is assumed to be Gaussian and correlated to the sources. The tradeoff between the distortion of the sources and the interference estimation error is studied;information-theoretic outer and inner bounds based on ideas from rate-distortion theory and hybrid coding are derived, respectively. More precisely, the outer bound is found by assuming additional knowledge at each user;the inner bound, however, is obtained by analyzing the distortion of a layered hybrid scheme based on proper power splitting, Costa and Wyner-Ziv coding. lowdelay and complexity coding schemes based on analog mapping are next proposed. More specifically, parametric mappings based on linear and sawtooth curves are studied and optimized by minimizing an upper bound on the system's distortion;nonparametric mappings based on joint optimization between the encoder and the decoder using an iterative algorithm are designed. Numerical results show that for the special cases that are previously considered by Abou Saleh et al. (with no fading), the derived outer bound is tighter and the proposed hybrid scheme has a lower complex structure with no loss in performance. In addition, the proposed lowdelay nonlinear schemes outperform the linear scheme and perform relatively close to the inner bound under certain system settings.
In this paper, we consider the design of forward error correction tailored specifically for the low end-to-end latency requirements in 5G networks. We present experimental results that highlight a number of issues wit...
详细信息
In this paper, we consider the design of forward error correction tailored specifically for the low end-to-end latency requirements in 5G networks. We present experimental results that highlight a number of issues with conventional approaches and then introduce a new lowdelay code construction that achieves a superior throughput-delay tradeoff. We analyze its performance both mathematically and experimentally. The mathematical analysis of throughput and delay requires the development of a number of novel analytic tools based on both queuing and coding theories. We implement the lowdelay code and evaluate its performance in an experimental test bed.
codingdelay has emerged as a significant obstacle to wider adoption of Higher Order Ambisonics (HOA), a promising flexible format employed in representation and coding of spatial audio. lowdelay is critical in many ...
详细信息
ISBN:
(纸本)9798350344868;9798350344851
codingdelay has emerged as a significant obstacle to wider adoption of Higher Order Ambisonics (HOA), a promising flexible format employed in representation and coding of spatial audio. lowdelay is critical in many applications, such as virtual reality, gaming, and online music performance, a good subset of which further require lossless compression. However, major advances in spatial audio codec design often sacrifice lowdelay in order to maximize compression gains. We present a new lossless, ultra-lowdelay HOA codec, optimized to take advantage of both the spatial and temporal redundancies in HOA data, while maintaining an extremely lowdelay. The presented codec has an algorithmic delay of one single sample, at the cost of increased computational complexity. This codec outperforms the state-of-the-art for lossless, low-delay HOA coding, both in terms of delay and bitrate.
暂无评论