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Search Results: 1 - 10 of 26669 matches for " Martin Fleury "
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Error Resilient IPTV for an IEEE 802.16e Channel  [PDF]
Laith Al-Jobouri, Martin Fleury, Mohammed Ghanbari
Wireless Engineering and Technology (WET) , 2011, DOI: 10.4236/wet.2011.22010
Abstract: Data-partitioning of IPTV video streams is a way of providing graceful quality degradation in a form that will work in good and difficult wireless channel conditions, as experienced by mobile devices. This paper’s proposal is to combine redundant slice protection along with an adaptive channel coding scheme that is also proposed in the paper. Adaptive channel coding is achieved by retransmission when necessary of additional redundant data to reconstruct corrupted packets. In the proposal, outright packet loss is provided for by a form of redundant slice protection. The paper finds that it is preferable: not to simply protect only the highest priority packets; that a moderate quantization level should be employed; and that video quality is differentiated by content type. It is important also to configure the partitioning correctly to remove inter-partition dependencies when possible.
Adaptive Packet-Level Interleaved FEC for Wireless Priority-Encoded Video Streaming
Rouzbeh Razavi,Martin Fleury,Mohammed Ghanbari
Advances in Multimedia , 2009, DOI: 10.1155/2009/982867
Abstract: Packet-level Forward Error Control (FEC) for video streaming over a wireless network has received comparatively limited investigation, because of the delay introduced by the need to assemble a group of packets. However, packet-level interleaving when combined with FEC presents a remedy to time-correlated error bursts, though it can further increase delay if this issue is not addressed. This paper proposes adapting the overall degree of interleaved packet-level FEC according to the display deadlines of packets, transmit buffer occupation, and estimated video input to the wireless channel, all of which address the issue of delay. To guard against estimation error, the scheme applies a conservative adaptation policy, which accounts for picture type importance to ensure that display deadlines are met, thus avoiding this defect of interleaving. The paper additionally introduces a greedy algorithm that effectively groups packet-level FEC protection according to packet priority. Priority encoding adds extra protection during deep fades. As feedback is not required, the interleaving scheme is suitable for all forms of video broadcast. A Bluetooth piconet demonstrates the packet-level FEC interleaving scheme, which provides higher quality delivered video compared to the industry-standard Pro-MPEG Cop#3r2 interleaving scheme.
Distortion-Based Slice Level Prioritization for Real-Time Video over QoS-Enabled Wireless Networks
Ismail A. Ali,Martin Fleury,Mohammed Ghanbari
Advances in Multimedia , 2012, DOI: 10.1155/2012/319785
Abstract: This paper presents a prioritization scheme based on an analysis of the impact on objective video quality when dropping individual slices from coded video streams. It is shown that giving higher-priority classified packets preference in accessing the wireless media results in considerable quality gain (up to 3?dB in tests) over the case when no prioritization is applied. The proposed scheme is demonstrated for an IEEE 802.11e quality-of-service- (QoS-) enabled wireless LAN. Though more complex prioritization systems are possible, the proposed scheme is crafted for mobile interactive or user-to-user video services and is simply implemented within the Main or the Baseline profiles of an H.264 codec. 1. Introduction There have recently emerged two forms of video streaming to mobile devices. The first, HTTP adaptive streaming [1], employing reliable TCP transport, has no need to protect the video stream against channel errors but is subject to delays. These delays mainly arise from the repeated transmissions that TCP imposes whenever packets are lost. Additionally, delay may occur due to the pull-based nature of the service. Therefore, though suitable for some forms of one-way commercial streaming, HTTP adaptive streaming is unsuitable for interactive services such as video conferencing. It is also unsuitable for mobile user-to-user streaming, because of the need to create multiple copies of the same video at different resolutions and set up a complex management structure to allow client access to an appropriate stream. Therefore, a second native form of streaming is necessary for delay- or storage-intolerant video streaming, and it is this form of streaming that is the subject of this paper. In this form of streaming [2], video is pushed from the server without the need for a feedback channel to make continual client requests. The Real-time Transport Protocol (RTP) with underlying Internet Protocol (IP)/User Datagram Protocol (UDP) for network routing and transport updates the client-side decoder with synchronization information. If MPEG-2 Transport Stream (TS) packets are multiplexed within each RTP packet, then audio can accompany video in a single packet stream. Adaptive bitrate adjustments (through scalable coding or transcoding) can occur, based on performance metrics carried by Real-time Transport Control Protocol (RTCP) packets, and pseudo-VCR functionality, if needed, is available through the Real-time Streaming Protocol (RTSP). When mobile video streaming in native mode with IP/UDP/RTP packetization, there is a need to avoid periodic increased
Applying Multi-Connection Video Streaming to WiMAX Broadband Wireless
Salah S. Al-Majeed,Martin Fleury
Journal of Communications , 2010, DOI: 10.4304/jcm.5.8.583-592
Abstract: Streaming a single video over multiple TCPFriendly Rate Control (TFRC) connections is a way of separately coping with both wireless channel losses and traffic congestion, without the need for cross-layer intervention or retransmission delay at the data-link layer. At the same time, the wireless channel is properly utilized, as throughput improves with an increasing number of connections. Nevertheless over IEEE 802.16e (mobile WiMAX), tuning is needed to select the number of connections and the Time Division Duplex (TDD) frame size. The paper assesses the impact on video quality of packet drops due both to channel loss over a WiMAX access link and router buffer overflow across an all-IP network, consisting of broadband wireless access and core network. The paper also considers end-to-end delay and start-up delay when employing several connections. Results show that provided the TDD frame size is selected appropriately then using multiple connections preserves video quality and improves wireless channel utilization, with a minimal impact on end-to-end delay. As a trade-off, there is an increase in start-up delay arising from the need to avoid possible buffer underflow.
Unequal Protection of Video Streaming through Adaptive Modulation with a Trizone Buffer over Bluetooth Enhanced Data Rate
Rouzbeh Razavi,Martin Fleury,Mohammed Ghanbari
EURASIP Journal on Wireless Communications and Networking , 2007, DOI: 10.1155/2008/658794
Abstract: Bluetooth enhanced data rate wireless channel can support higher-quality video streams compared to previous versions of Bluetooth. Packet loss when transmitting compressed data has an effect on the delivered video quality that endures over multiple frames. To reduce the impact of radio frequency noise and interference, this paper proposes adaptive modulation based on content type at the video frame level and content importance at the macroblock level. Because the bit rate of protected data is reduced, the paper proposes buffer management to reduce the risk of buffer overflow. A trizone buffer is introduced, with a varying unequal protection policy in each zone. Application of this policy together with adaptive modulation results in up to 4 ¢ € ‰dB improvement in objective video quality compared to fixed rate scheme for an additive white Gaussian noise channel and around 10 ¢ € ‰dB for a Gilbert-Elliott channel. The paper also reports a consistent improvement in video quality over a scheme that adapts to channel conditions by varying the data rate without accounting for the video frame packet type or buffer congestion.
Power-Constrained Fuzzy Logic Control of Video Streaming over a Wireless Interconnect
Rouzbeh Razavi,Martin Fleury,Mohammed Ghanbari
EURASIP Journal on Advances in Signal Processing , 2008, DOI: 10.1155/2008/560749
Abstract: Wireless communication of video, with Bluetooth as an example, represents a compromise between channel conditions, display and decode deadlines, and energy constraints. This paper proposes fuzzy logic control (FLC) of automatic repeat request (ARQ) as a way of reconciling these factors, with a 40% saving in power in the worst channel conditions from economizing on transmissions when channel errors occur. Whatever the channel conditions are, FLC is shown to outperform the default Bluetooth scheme and an alternative Bluetooth-adaptive ARQ scheme in terms of reduced packet loss and delay, as well as improved video quality.
Unequal Protection of Video Streaming through Adaptive Modulation with a Trizone Buffer over Bluetooth Enhanced Data Rate
Razavi Rouzbeh,Fleury Martin,Ghanbari Mohammed
EURASIP Journal on Wireless Communications and Networking , 2008,
Abstract: Bluetooth enhanced data rate wireless channel can support higher-quality video streams compared to previous versions of Bluetooth. Packet loss when transmitting compressed data has an effect on the delivered video quality that endures over multiple frames. To reduce the impact of radio frequency noise and interference, this paper proposes adaptive modulation based on content type at the video frame level and content importance at the macroblock level. Because the bit rate of protected data is reduced, the paper proposes buffer management to reduce the risk of buffer overflow. A trizone buffer is introduced, with a varying unequal protection policy in each zone. Application of this policy together with adaptive modulation results in up to 4 dB improvement in objective video quality compared to fixed rate scheme for an additive white Gaussian noise channel and around 10 dB for a Gilbert-Elliott channel. The paper also reports a consistent improvement in video quality over a scheme that adapts to channel conditions by varying the data rate without accounting for the video frame packet type or buffer congestion.
Protecting H.264/AVC Data-Partitioned Video Streams over Broadband WiMAX
Laith Al-Jobouri,Martin Fleury,Mohammed Ghanbari
Advances in Multimedia , 2012, DOI: 10.1155/2012/129517
Abstract: Broadband wireless technology, though aimed at video services, also poses a potential threat to video services, as wireless channels are prone to error bursts. In this paper, an adaptive, application-layer Forward Error Correction (FEC) scheme protects H.264/AVC data-partitioned video. Data partitioning is the division of a compressed video stream into partitions of differing decoding importance. The paper determines whether equal error protection (EEP) through FEC of all partition types or unequal error protection (UEP) of the more important partition type is preferable. The paper finds that, though UEP offers a small reduction in bitrate, if EEP is employed, there are significant gains (several dBs) in video quality. Overhead from using EEP rather than UEP was found to be around 1% of the overall bitrate. Given that data partitioning already reduces errors through packet size reduction and differentiation of coding data, EEP with data partitioning is a practical means of protecting user-based video streaming. The gain from employing EEP is shown to be higher quality video to the user, which will result in a greater take-up of video services. The results have implications for other forms of prioritized video streaming. 1. Introduction Portable devices are proliferating, as the era of the wired Internet draws to a close and 4G wireless systems, and their successors [1] bring greater bandwidth capacity to access networks. User-based video-streaming applications are anticipated to be a key to the success of broadband wireless access networks such as IEEE 802.16e (mobile WiMAX) [2]. WiMAX itself is proving to be attractive in many areas where existing cell phone coverage is sparse or nonexistent. However, the migration of Internet applications to 4G wireless access presents a problem for video-streaming applications. This is because wireless channels are fundamentally error prone, whereas compression, for most of its coding gain, depends upon predictive coding. Consequentially, because of source-coding data dependencies, errors can disrupt a compressed video bitstream, and these errors can subsequently propagate in space and time. In the multimedia research world, unequal error protection (UEP) through channel coding or forward error correction (FEC) has proved to be a rich area of investigation. Many schemes (some of which are reviewed in Section 2) have been proposed that map differential protection onto prioritized coded video data. However, there are strong signs that, in the commercial world, video service providers, in the interests of video content
Measurement and Analysis Study of Congestion Detection for Internet Video Streaming
Marcos Paredes Farrera,Martin Fleury,Ken Guild,Mohammed Ghanbari
Journal of Communications , 2010, DOI: 10.4304/jcm.5.2.169-177
Abstract: A measurement study was conducted of video streaming across a testbed with routers typical of those found at bottlenecks on the wired Internet. During ‘bursty’ traffic packet loss was not always fairly distributed between background flows and a video stream. The paper shows that packet-by-packet end-to-end delay, an alternative metric, has the ability to closely track queuing delay, responding to available bandwidth in a timely manner. A wider issue considered by the paper is to what extent one-way delay across a network path that includes bottleneck links can act to detect congestion.
Emergency Video Multi-Path Transfer over Ad Hoc Wireless Networks
Nadia Qadri,Martin Fleury,Muhammad Altaf,Mohammed Ghanbari
Journal of Communications , 2009, DOI: 10.4304/jcm.4.5.329-338
Abstract: Ad Hoc networks utilize multi-hop radio relay without the need for a base station, supporting mobility and allowing them to be quickly deployed in an emergency. Real-time video communication across an ad hoc network allows helpers to better understand the nature of the problem within a disaster area but the lack of centralized routing and network resource management is challenging, particularly if the wireless nodes have limited processing power. Multi-path solutions have been proposed for video transfer. This paper investigates two practical schemes, Video Redundancy Coding and a proposal of the paper, H.264 codec redundant frames. The paper reports that redundant frames when used in combination with multipath do result in as much as 10 dB improvement in delivered video quality, making the difference between acceptable and unacceptable visual communication in a disaster scenario.
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