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
References
[1]
O. Oyman and S. Singh, “Quality of experience for HTTP adaptive streaming services,” IEEE Communications Magazine, vol. 50, no. 4, pp. 20–27, 2012.
[2]
B. Bing, 3D and HD Broadband Video Networking, Artech-House, Boston, Mass, USA, 2010.
[3]
I. E. G. Richardson, H.264 and MPEG-4 Video Compression, John Wiley & Sons, Chichester, UK, 2004.
[4]
P. Haskell and D. Messerschmitt, “Resynchronization of motion compensated video affected by ATM cell loss,” in Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '92), pp. 545–548, March 1992.
[5]
M. M. Hannuksela, Y. K. Wang, and M. Gabbouj, “Isolated regions in video coding,” IEEE Transactions on Multimedia, vol. 6, no. 2, pp. 259–267, 2004.
[6]
R. M. Schreier and A. Rothermel, “Motion adaptive intra refresh for low-delay video coding,” in Proceedings of the International Conference on Consumer Electronics (ICCE '06), pp. 453–454, Las Vegas, Nev, USA, January 2006.
[7]
“Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,” IEEE Std 802. 11e-2005 (Amendment to IEEE Std 802. 11, 1999 Edition (Reaff 2003), 2005.
[8]
I. Ali, S. Moiron, M. Fleury, and M. Ghanbari, “Prioritized packetization for video with intra-refresh macroblock line,” in Proceedings of the IEEE International Conference on Multimedia and Expo (ICME '11), pp. 1–6, July 2011.
[9]
I. Ali, S. Moiron, M. Fleury, and M. Ghanbari, “Enhanced prioritization for video streaming over QoS-enabled wireless networks,” in Proceedings of the IEEE Wireless Advanced (WiAd '11), pp. 268–272, June 2011.
[10]
I. Ali, S. Moiron, M. Fleury, and M. Ghanbari, “Enhanced prioritization for video streaming over wireless home networks with IEEE 802. 11e,” in Proceedings of the IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB '11), pp. 1–6, June 2011.
[11]
I. Ali, M. Fleury, and M. Ghanbari, “Content-aware intra-refresh for video streaming over lossy links,” in Proceedings of the IEEE International Conference on Consumer Electronics (ICCE '12), pp. 118–119, January 2012.
[12]
A. Ksentini, M. Naimi, and A. Guéroui, “Toward an improvement of H.264 video transmission over IEEE 802.11e through a cross-layer architecture,” IEEE Communications Magazine, vol. 44, no. 1, pp. 107–114, 2006.
[13]
G. C？té and F. Kossentini, “Optimal intra coding of blocks for robust video communication over the Internet,” Signal Processing, vol. 15, no. 1, pp. 25–34, 1999.
[14]
X. Wang, C. Kodikara, A. H. Sadka, and A. M. Kondoz, “Robust GOB intra refresh scheme for H.264/AVC video over UMTS,” in Proceedings of the 6th IEE International Conference on 3G and Beyond, pp. 1–4, November 2005.
[15]
J. T. Wang and P. C. Chang, “Error-propagation prevention technique for real-time video transmission over ATM networks,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 9, no. 3, pp. 513–523, 1999.
[16]
W. T. Tan, E. Setton, and J. Apostolopoulos, “Lossless FMO and slice structure modification for compressed H.264 video,” in Proceedings of the 14th IEEE International Conference on Image Processing (ICIP '07), vol. 4, pp. IV285–IV288, September 2007.
[17]
I. A. Ali, M. Fleury, and M. Ghanbari, “Congestion-resistant scalable media stream mapping for an IEEE 802.11E sensor network,” in Proceedings of the 17th IEEE International Conference on Image Processing (ICIP '10), pp. 2901–2904, September 2010.
[18]
X. Li, T. Ren, and J. Xu, “A cross-layer design for transmission of scalable H.264 video over IEEE 802.11e networks,” in Proceedings of the 1st International Conference on Computational Problem-Solving (ICCP '10), pp. 306–309, December 2010.
[19]
R. Soni, N. Chilamkurti, G. Giambene, and S. Zeadally, “A cross-layer design for H.264 video stream over wireless local area networks,” in Proceedings of the International Symposium on Computer Science and its Applications (CSA '08), pp. 387–392, October 2008.
[20]
W. T. Chen, T. C. Lin, Y. C. Chang, and J. C. Chen, “Dynamic packet selection for H.264 video streaming over IEEE 802.11e WLANs,” in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC '08), pp. 3133–3138, March 2008.
[21]
Q. Liu, Z. Zou, and C. W. Chen, “A deadline-aware virtual contention free EDCA scheme for H.264 video over IEEE 802.11e wireless networks,” in Proceedings of the IEEE International Symposium of Circuits and Systems (ISCAS '11), pp. 625–628, May 2011.
[22]
T. Wiegand, G. J. Sullivan, G. Bj？ntegaard, and A. Luthra, “Overview of the H.264/AVC video coding standard,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, no. 7, pp. 560–576, 2003.
[23]
Y. K. Wang, M. M. Hannuksela, V. Varsa, A. Hourunranta, and M. Gabbouj, “The error concealment feature in the H.26L test model,” in Proceedings of the International Conference on Image Processing (ICIP '02), vol. 2, pp. 729–732, September 2002.
[24]
F. Agboma and A. Liotta, “Addressing user expectations in mobile content delivery,” Mobile Information Systems., vol. 3, no. 3-4, pp. 153–164, 2007.
[25]
R. MacKenzie, D. Hands, and T. O'Farrell, “QoS of video delivered over 802.11e WLANs,” in Proceedings of the IEEE International Conference on Communications (ICC '09), pp. 1246–1250, June 2009.
[26]
C. Casetti, C. F. Chiasserini, L. Merello, and G. Olmo, “Supporting multimedia traffic in 802.11e WLANs,” in Proceedings of the IEEE Vehicular Technology Conference (VTC '05), pp. 2340–2344, May 2005.
[27]
R. Haywood, S. Mukherjee, and X. H. Peng, “Investigation of H.264 video streaming over an IEEE 802.11e EDCA wireless testbed,” in Proceedings of the IEEE International Conference on Communications (ICC '09), pp. 1516–1520, June 2009.
