CiteULike: p2pstreaming's distortion

Improvement on Rate-Distortion Performance of H.264 Rate Control in Low Bit Rate

Shu Zhou — 2008-05-13T15:00:51-00:00

Circuits and Systems for Video Technology, IEEE Transactions on, Vol. 17, No. 8. (2007), pp. 996-1006.

This paper points out some defects in the techniques used in H.264 rate control and presents several new algorithms to improve them. The improved algorithm has the following main features: 1) the bits allocated to each P-frame is proportional to the local motion in it, i.e, more bits are allocated to a frame if the local motion in it is stronger; 2) the quantization parameter for I-frame is choosed based on a new bits allocation scheme for I-frame; 3)the quantization parameter calculation is based on a simple encoding complexity prediction scheme, which is more robust and of less complexity than the quadratic model used by H.264 in low bit rate video coding. Experimental results and analysis show that the improved rate-control scheme has significantly increased the average peak signal-to-noise ratio up to 1.53 dB, reduced the variation of buffer level, improved the perpetual quality of the reconstructed video and reduced the computation complexity.

An Accurate Low-Complexity Rate Control Algorithm Based on (ρ, Eq)-Domain

S Milani — 2008-05-13T14:56:17-00:00

Circuits and Systems for Video Technology, IEEE Transactions on, Vol. 18, No. 2. (2008), pp. 257-262.

<para> The standard H.264/AVC defines an efficient coding architecture both for coding applications where bandwidth or storage capacity is limited (e.g., video telephony or video conferencing over mobile channels and devices) and for applications that require high reconstruction quality and bit rate (e.g., HDTV). Since its main applications concern video communication over time-varying bandwidth channels, the bit rate has to be controlled with scalable algorithms that can be implemented on low resource devices. The paper describes a rate control algorithm that needs reduced memory area and complexity compared to other ones. The number of coded bits for each frame is accurately predicted through the percentage of null quantized transform coefficients, which is related to the quantization step via the energy of the quantized signal. It is possible to design a rate control algorithm based on this model that provides a good compression performance at a low computational cost. </para>

Frame bit allocation for the H.264/AVC video coder via Cauchy-density-based rate and distortion models

N Kamaci — 2008-05-13T14:48:17-00:00

Circuits and Systems for Video Technology, IEEE Transactions on, Vol. 15, No. 8. (2005), pp. 994-1006.

Based on the observation that a Cauchy density is more accurate in estimating the distribution of the ac coefficients than the traditional Laplacian density, rate and distortion models with improved accuracy are developed. The entropy and distortion models for quantized discrete cosine transform coefficients are justified in a frame bit-allocation application for H.264. Extensive analysis with carefully selected anchor video sequences demonstrates a 0.24-dB average peak signal-to-noise ratio (PSNR) improvement over the JM 8.4 rate control algorithm, and a 0.33-dB average PSNR improvement over the TM5-based bit-allocation algorithm that has recently been proposed for H.264 by Li et al. The analysis also demonstrates 20% and 60% reductions in PSNR variation among the encoded pictures when compared to the JM 8.4 rate control algorithm and the TM5-based bit-allocation algorithm, respectively.

Rate-Distortion Optimization of Rate Control for H.264 With Adaptive Initial Quantization Parameter Determination

Hanli Wang — 2008-05-13T14:35:48-00:00

Circuits and Systems for Video Technology, IEEE Transactions on, Vol. 18, No. 1. (2008), pp. 140-144.

A rate-distortion (R-D) optimization rate control (RC) algorithm with adaptive initialization is presented for H.264. First, a linear distortion-quantization (D-Q) model is introduced and thus a close-form solution is developed to derive optimal quantization parameters (Qp)for encoding each macroblock. Then we exploit to determine the initial Qp efficiently and adaptively according to the content of video sequences. The experimental results demonstrate that the proposed algorithm can achieve better R-D performance than that of other two RC algorithms including the algorithm JVT-G012 which is the current recommended RC scheme implemented in the H.264 reference software JM9.5.

Video Multicast over Wireless Mesh Networks with Scalable Video Coding (SVC)

X Zhu — 2008-05-09T21:59:02-00:00

(2008)

Distributed Channel Time Allocation and Rate Adaptation for Multi-User Video Streaming Over Wireless Home Networks

Xiaoqing Zhu — 2008-05-09T18:26:23-00:00

Image Processing, 2007. ICIP 2007. IEEE International Conference on, Vol. 5 (2007), pp. V - 69-V - 72.

Simultaneous support of multiple video streaming sessions over a shared wireless network requires careful resource allocation to achieve high utilization while dynamically adapting to network and video fluctuations. We propose a distributed algorithm for channel time allocation among multiple video streams, and investigate several heuristic packet pruning schemes for rate adaptation of high-definition (HD) video streams. Simulation results are presented for streaming multiple HD video sequences over an 802.11a network. In comparison with TCP-Friendly Rate Control (TFRC) and a basic scheme without rate adaptation, it is shown that the proposed scheme can sustain higher video quality with lower packet delivery delay.

Rate-distortion optimized distributed packet scheduling of multiple video streams over shared communication resources

J Chakareski — 2008-05-09T05:06:07-00:00

Multimedia, IEEE Transactions on, Vol. 8, No. 2. (2006), pp. 207-218.

We consider the problem of distributed packet selection and scheduling for multiple video streams sharing a communication channel. An optimization framework is proposed, which enables the multiple senders to coordinate their packet transmission schedules, such that the average quality over all video clients is maximized. The framework relies on rate-distortion information that is used to characterize a video packet. This information consists of two quantities: the size of the packet in bits, and its importance for the reconstruction quality of the corresponding stream. A distributed streaming strategy then allows for trading off rate and distortion, not only within a single video stream, but also across different streams. Each of the senders allocates to its own video packets a share of the available bandwidth on the channel in proportion to their importance. We evaluate the performance of the distributed packet scheduling algorithm for two canonical problems in streaming media, namely adaptation to available bandwidth and adaptation to packet loss through prioritized packet retransmissions. Simulation results demonstrate that, for the difficult case of scheduling nonscalably encoded video streams, our framework is very efficient in terms of video quality, both over all streams jointly and also over the individual videos. Compared to a conventional streaming system that does not consider the relative importance of the video packets, the gains in performance range up to 6 dB for the scenario of bandwidth adaptation, and even up to 10 dB for the scenario of random packet loss adaptation.

Rate-distortion optimized streaming of packetized media

PA Chou — 2008-05-05T05:43:21-00:00

Multimedia, IEEE Transactions on, Vol. 8, No. 2. (2006), pp. 390-404.

This paper addresses the problem of streaming packetized media over a lossy packet network in a rate-distortion optimized way. We show that although the data units in a media presentation generally depend on each other according to a directed acyclic graph, the problem of rate-distortion optimized streaming of an entire presentation can be reduced to the problem of error-cost optimized transmission of an isolated data unit. We show how to solve the latter problem in a variety of scenarios, including the important common scenario of sender-driven streaming with feedback over a best-effort network, which we couch in the framework of Markov decision processes. We derive a fast practical algorithm for nearly optimal streaming in this scenario, and we derive a general purpose iterative descent algorithm for locally optimal streaming in arbitrary scenarios. Experimental results show that systems based on our algorithms have steady-state gains of 2-6 dB or more over systems that are not rate-distortion optimized. Furthermore, our systems essentially achieve the best possible performance: the operational distortion-rate function of the source at the capacity of the packet erasure channel.

Congestion-Distortion Optimized Peer-to-Peer Video Streaming

E Setton — 2008-05-05T04:31:51-00:00

Image Processing, 2006 IEEE International Conference on (2006), pp. 721-724.

In live peer-to-peer streaming, a video stream is transmitted to a large population of viewers, through the use of the uplink bandwidth of participating peers. This approach overcomes the cost of large-scale deployment of such services. An essential problem of this type of system is to limit the incurred congestion. In particular, overwhelming the uplink of some peers would create a large increase in the latency of the system and make this application less compelling. In this work we focus on limiting the congestion in a peer-to-peer network where multiple multicast trees are used to distribute video to a large set of receivers. We present the idea of congestion-distortion optimized streaming which aims at maximizing decoded video quality while limiting network congestion. We describe how this type of media scheduling maintains high video quality even for low latencies, and extend its usage to the peer-to-peer scenario. Experiments over a simulated network of 300 peers illustrate the benefits of the suggested approach

Analysis of video transmission over lossy channels

K Stuhlmuller — 2006-07-30T05:53:54-00:00

Selected Areas in Communications, IEEE Journal on, Vol. 18, No. 6. (2000), pp. 1012-1032.

A theoretical analysis of the overall mean squared error (MSE) in hybrid video coding is presented for the case of error prone transmission. Our model covers the complete transmission system including the rate-distortion performance of the video encoder, forward error correction, interleaving, and the effect of error concealment and interframe error propagation at the video decoder. The channel model used is a 2-state Markov model describing burst errors on the symbol level. Reed-Solomon codes are used for forward error correction. Extensive simulation results using an H.263 video codec are provided for verification. Using the model, the optimal tradeoff between INTRA and INTER coding as well as the optimal channel code rate can be determined for given channel parameters by minimizing the expected MSE at the decoder. The main focus of this paper is to show the accuracy of the derived analytical model and its applicability to the analysis and optimization of an entire video transmission system