Performance Evaluation of MPEG-4 Video Transmission over IP-Networks: Best-Effort and Quality-of-Service

The demand for video communication over internet has been growing rapidly in recent years and the quality of video has become a challenging issue for video transmission. Different types of video coding standards like MPEG-2 and MPEG-4 have been developed to support application like video transmission. MPEG-2 which requires high bit rate transmission has been successful video standard for DVD and satellite digital broadcasting. On the other hand, MPEG-4 supports low bit rate and is suitable for transmitting video over IP networks. In this paper, MPEG-4 Video standard has been used for evaluating the performance of video transmission over two IP networks:- Best-effort and Quality of Service (QoS). For both of the best-effort and QoS IP networks, peak signal noise ratio (PSNR), throughput, frame and packet statistics have been considered as performance metrics. The calculated values of these performance metrics reflect that video transmission over QoS IP network is better than that of the best-effort network. Keywords: video transmission, mpeg, ip networks, best-effort, quality of service, ns-

A comparative survey on high dynamic range video compression

International audienceHigh dynamic range (HDR) video compression has until now been approached by using the high profile of existing state-of-the-art H.264/AVC (Advanced Video Coding) codec or by separately encoding low dynamic range (LDR) video and the residue resulted from the estimation of HDR video from LDR video. Although the latter approach has a distinctive advantage of providing backward compatibility to 8-bit LDR displays, the superiority of one approach to the other in terms of the rate distortion trade-off has not been verified yet. In this paper, we first give a detailed overview of the methods in these two approaches. Then, we experimentally compare two approaches with respect to different objective and perceptual metrics, such as HDR mean square error (HDR MSE), perceptually uniform peak signal to noise ratio (PU PSNR) and HDR visible difference predictor (HDR VDP). We first conclude that the optimized methods for backward compatibility to 8-bit LDR displays are superior to the method designed for high profile encoder both for 8-bit and 12-bit mappings in terms of all metrics. Second, using higher bit-depths with a high profile encoder is giving better rate-distortion performances than employing an 8-bit mapping with an 8-bit encoder for the same method, in particular when the dynamic range of the video sequence is high. Third, rather than encoding of the residue signal in backward compatible methods, changing the quantization step size of the LDR layer encoder would be sufficient to achieve a required quality. In other words, the quality of tone mapping is more important than residue encoding for the performance of HDR image and video coding

Adaptive real time wireless data transmission using superposition coding with feedback of channel state information

High quality data transmission services are an important issue for broadband wireless access (BWA) systems. This paper deals with the design issues of a real-time wireless data transmission which provides unequal error protection (UEP) over an additive white Gaussian noise (AWGN) channel. Traditionally, transmission is made from a one bit stream at one level of power (for example, pulse amplitude modulation (PAM)) but using different techniques to exploit the available bandwidth. Using superposition coding, the real time data bit stream can be divided into two bit streams. The first bit stream represents the region of high priority (HP) while the second represents low priority (LP) region. These two bit streams are modulated separately, and superimposed together with two different levels of power to achieve the UEP at the receiver side. Feedback of the channel state information (CSI) is used by adaptive channel in the physical layer such that the current available bandwidth is used efficiently. In this proposed scheme, the same design metrics, namely time, bandwidth and power are used to increase the transmission efficiency. The performance of the proposed scheme is compared with the traditional, 2-PAM and 4-PAM schemes. Unlike the traditional schemes, the results show that our scheme provides a higher data rate at an acceptable bit error rate (BER) when the channel is in good condition. When channel quality is degraded, a reduced data rate is applied in contrast with the traditional schemes. As compared with the traditional 4-PAM scheme, the proposed scheme gives a good error performance for the HP bit stream with 0.2 dB gain increase at BER of 10-5, and exhibited a 4 dB gain when the channel condition is bad

Transform domain distributed video coding using larger transform blocks

Distributed Video Coding (DVC) displays promising performance at low spatial resolutions but begins to struggle as the resolution increases. One of the limiting aspects is its 4x4 block size of Discrete Cosine Transform (DCT) which is often impractical at higher resolutions. This paper investigates the impact of exploiting larger DCT block sizes on the performance of transform domain DVC at higher spatial resolutions. In order to utilize a larger block size in DVC, appropriate quantisers have to be selected and this has been solved by means of incorporating a content-aware quantisation mechanism to generate image specific quantisation matrix for any DCT block size. Experimental results confirm that the larger 8x8 block size consistently exhibit superior RD performance for CIF resolution sequences compared to the smaller 4x4 block sizes. Significant PSNR improvement has been observed for 16x16 block size at 4CIF resolution with up to 1.78dB average PSNR gain compared to its smaller block alternatives

Perceptually-Driven Video Coding with the Daala Video Codec

The Daala project is a royalty-free video codec that attempts to compete with the best patent-encumbered codecs. Part of our strategy is to replace core tools of traditional video codecs with alternative approaches, many of them designed to take perceptual aspects into account, rather than optimizing for simple metrics like PSNR. This paper documents some of our experiences with these tools, which ones worked and which did not. We evaluate which tools are easy to integrate into a more traditional codec design, and show results in the context of the codec being developed by the Alliance for Open Media.Comment: 19 pages, Proceedings of SPIE Workshop on Applications of Digital Image Processing (ADIP), 201