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Investigations Of The Error Resilient Rate Distortion Optimization For H264 Video Transport Over Packet Lossy Channels
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Book Synopsis Investigations of the Error Resilient Rate Distortion Optimization for H.264 Video Transport Over Packet Lossy Channels by : Hao Zeng
Download or read book Investigations of the Error Resilient Rate Distortion Optimization for H.264 Video Transport Over Packet Lossy Channels written by Hao Zeng and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Error Resilient Packet Switched H.264 Video Telephony Over Third Generation Networks by : Muneeb Dawood
Download or read book Error Resilient Packet Switched H.264 Video Telephony Over Third Generation Networks written by Muneeb Dawood and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Real-time video communication over wireless networks is a challenging problem becausewireless channels suffer from fading, additive noise and interference, which translateinto packet loss and delay. Since modern video encoders deliver video packets withdecoding dependencies, packet loss and delay can significantly degrade the video qualityat the receiver. Many error resilience mechanisms have been proposed to combat packetloss in wireless networks, but only a few were specifically designed for packet switchedvideo telephony over Third Generation (3G) networks. The first part of the thesis presents an error resilience technique for packet switchedvideo telephony that combines application layer Forward Error Correction (FEC) withrateless codes, Reference Picture Selection (RPS) and cross layer optimization. Ratelesscodes have lower encoding and decoding computational complexity compared to traditionalerror correcting codes. One can use them on complexity constrained hand-helddevices. Also, their redundancy does not need to be fixed in advance and any number ofencoded symbols can be generated on the fly. Reference picture selection is used to limitthe effect of spatio-temporal error propagation. Limiting the effect of spatio-temporalerror propagation results in better video quality. Cross layer optimization is used tominimize the data loss at the application layer when data is lost at the data link layer. Experimental results on a High Speed Packet Access (HSPA) network simulator forH. 264 compressed standard video sequences show that the proposed technique achievessignificant Peak Signal to Noise Ratio (PSNR) and Percentage Degraded Video Duration(PDVD) improvements over a state of the art error resilience technique known asInteractive Error Control (IEC), which is a combination of Error Tracking and feedbackbased Reference Picture Selection. The improvement is obtained at a cost of higherend-to-end delay. The proposed technique is improved by making the FEC (Rateless code) redundancychannel adaptive. Automatic Repeat Request (ARQ) is used to adjust the redundancyof the Rateless codes according to the channel conditions. Experimental results showthat the channel adaptive scheme achieves significant PSNR and PDVD improvementsover the static scheme for a simulated Long Term Evolution (LTE) network. In the third part of the thesis, the performance of the previous two schemes isimproved by making the transmitter predict when rateless decoding will fail. In thiscase, reference picture selection is invoked early and transmission of encoded symbolsfor that source block is aborted. Simulations for an LTE network show that this resultsin video quality improvement and bandwidth savings. In the last part of the thesis, the performance of the adaptive technique is improvedby exploiting the history of the wireless channel. In a Rayleigh fading wireless channel, the RLC-PDU losses are correlated under certain conditions. This correlation isexploited to adjust the redundancy of the Rateless code and results in higher Ratelesscode decoding success rate and higher video quality. Simulations for an LTE networkshow that the improvement was significant when the packet loss rate in the two wirelesslinks was 10%. To facilitate the implementation of the proposed error resilience techniques in practicalscenarios, RTP/UDP/IP level packetization schemes are also proposed for eacherror resilience technique. Compared to existing work, the proposed error resilience techniques provide bettervideo quality. Also, more emphasis is given to implementation issues in 3G networks.
Book Synopsis Efficient Transmission of Error Resilient H.264 Video Over Wireless Links by :
Download or read book Efficient Transmission of Error Resilient H.264 Video Over Wireless Links written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the advent of telecommunication technology, the need to transport multimedia content is increasing day by day. Successful video transmission over the wireless network faces a lot of challenges because of the limited resource and error prone nature of the wireless environment. To deal with these two challenges, not only the video needs to be compressed very efficiently but also the compression scheme needs to provide some error resilient features to deal with the high packet loss probability. In this thesis, we have worked with the H.264/ Advanced Video Coding (AVC) video compression standard since this is the most recent and most efficient video compression scheme. Also H.264 provides novel error resilient features e.g. slicing of the frame, Flexible Macroblock Ordering (FMO), data partitioning etc. In this thesis, we investigate how to utilize the error resilient schemes of H.264 to ensure a good quality picture at the receiving end. In the first part of the thesis, we find the optimum slice size that will enhance the quality of video transmission in a 3G environment. In the second part, we jointly optimize the data partitioning property and partial reliability extension property of the new transport layer protocol, Stream Control Transmission Protocol (SCTP). In the third and last part, we focus more on the network layer issues. We obtain the optimum point of application layer Forward Error Correction (FEC) and Medium Access Control (MAC) layer retransmission in a capacity constrained network. We assume that the bit rate assigned for the video application is more than the video bit rate so that the extra capacity available can be used for error correction.
Book Synopsis Video Compression and Communications by : Lajos Hanzo
Download or read book Video Compression and Communications written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2007-10-22 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of Wireless Video Communications five years ago, the area of video compression and wireless transceivers has evolved even further. This new edition addresses a range of recent developments in these areas, giving cognizance to the associated transmission aspects and issues of error resilience. Video Compression and Communications has been updated and condensed yet remains all-encompassing, giving a comprehensive overview of the subject. Covering compression issues, coding delay, implementational complexity and bitrate, the book also looks at the historical perspective to video communication. New edition of successful and informative text, Wireless Video Communications Substantial new material has been added on areas such as H.264, MPEG4 coding and transceivers Clear presentation and broad scope make it essential for anyone interested in wireless communications Systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems. This book is ideal for postgraduates and researchers in communication systems but will also be a valuable reference to undergraduates, development and systems engineers of video compression applications as well as industrialists, managers and visual communications practitioners.
Book Synopsis Multimedia Networking and Coding by : Farrugia, Reuben A.
Download or read book Multimedia Networking and Coding written by Farrugia, Reuben A. and published by IGI Global. This book was released on 2012-12-31 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in multimedia communication systems have enhanced the need for improved video coding standards. Due to the inherent nature of video content, large bandwidths and reliable communication links are required to ensure a satisfactory level of quality experience; inspiring industry and research communities to concentrate their efforts in this emerging research area. Multimedia Networking and Coding covers widespread knowledge and research as well as innovative applications in multimedia communication systems. This book highlights recent techniques that can evolve into future multimedia communication systems, also showing experimental results from systems and applications.
Book Synopsis Rate-distortion Optimised Video Transmission Using Pyramid Vector Quantisation by : Syed Mohsin Matloob Bokhari
Download or read book Rate-distortion Optimised Video Transmission Using Pyramid Vector Quantisation written by Syed Mohsin Matloob Bokhari and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Video has become a key part of our daily digital lives. An increasing number of people are using video to document their lives and share their experiences through , sites such as YouTube and Facebook. Due to this ever increasing quantity of video content, it is clear that more efficient and robust video compression algorithms are needed. In this thesis video compression and transmission are investigated, specifically focused on High Definition (HD) video coding and wireless transmission. Unfor- tunately, the techniques relied upon for efficient compression are the same tech- niques that hinder robustness. This is because conventional video compression relies on inter-frame prediction (motion estimation), intra frame prediction and variable- length entropy encoding to achieve high compression ratios but, as a consequence, produces an encoded bitstream that is inherently sensitive to channel errors. There- fore, in order to ensure reliable and robust delivery over lossy channels, it is necessary to invoke various additional error detection and correction methods. In this thesis a technique called Pyramid Vector Quantisation (PVQ) is investig- ated. In contrast to the other methods, Pyramid Vector Quantisation has the ability to prevent error propagation through the use of fixed length codewords. This thesis introduces an efficient Rate Distortion Optimisation (RDO) algorithm for intra- mode PVQ which offers similar compression performance and visual quality to intra H.264/ AVC, intra VC-I, VC-3 and Motion JPEG 2000 while offering outstanding inherent error resilience. The results are reported for a range of representative 1080p HD video sequences. The error resilience performance of the enhanced PVQ codec is then evaluated for HD content in the context of a realistic (IEEE 802.11n) wireless environment. The impact of both uncorrelated and correlated channel errors is investigated. It is shown that PVQ provides high tolerance to corrupted data compared to the state-of-the- art H.264/ AVC while obviating the need for complex encoding tools. PVQ (without explicit error resilience tools and without error concealment) is able to significantly outperform H.264/ AVC (with error resilience tools and with error concealment) by up to I3.3dB PSNR for the same wireless simulation scenario. The benefit obtained by employing a Gaussian Markov Random Field (GMRF) based wavelet domain error concealment algorithm to post process erroneously re- ceived PVQ bitstreams is also investigated. It is shown that this algorithm leads to a further 2.5dB performance gain thus outperforming H.264/ AVC by up to 15.8dB PSNR. Overall, it is hoped that the results of this thesis demonstrate PVQ's feasib- ility for in-home HD video coding and transmission.
Book Synopsis Error-resilient Image and Video Coding Over Lossy Networks by : Yilong Liu
Download or read book Error-resilient Image and Video Coding Over Lossy Networks written by Yilong Liu and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid growth of the Internet and increasing bandwidth in the past decade has heightened the interest in robust transmission of image and video signals over error-prone links. Recent literatures highlight the multiple description (MD) coding as a promising approach to solve this problem. MD coding is a source coding technique that provides a graceful quality degradation in the presence of packet losses during transmission. Topics of interest to construct MD coders with high coding efficiency and robustness are studied in this thesis. To minimize the overall distortion of reconstructed image, we propose an edge-adaptive estimation algorithm that is able to capture the arbitrarily-oriented edges around the corrupted coefficients. It reconstructs the lost samples more accurately compared to the previously proposed methods in the literatures. A feature-oriented MD coding scheme is proposed by adopting this estimation algorithm to smartly identify the coefficients that are sensitive to packet loss. The redundancy is then inserted to each channel by jointly optimizing the subsets of sensitive coefficients and the related quantizers. The corrupted samples are reconstructed with the proposed estimation algorithm at the receiver. By introducing the extra prediction loops to the correlating transform based MD video coder, the mismatching error, i.e. the drift, incurred by the one-channel reconstruction is decreased. However, the problem of effective redundancy allocation is introduced by the drift coding. An efficient algorithm is developed to solve this problem. The proposed approach optimally adjusts the source coding rates for the correlating transform coefficients and drifts in a coordinated fashion. The proposed algorithms are implemented based on the image/video MD coding systems using DCT or wavelet transforms. The advantages of the introduced approaches to achieve high coding efficiency and error-resilience for transmission are demonstrated.
Book Synopsis IEEE ... Workshop on Multimedia Signal Processing by :
Download or read book IEEE ... Workshop on Multimedia Signal Processing written by and published by . This book was released on 2004 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Improving End-user Video Quality Through Error Concealment and Packet Importance Modeling by : Yueh-Lun Chang
Download or read book Improving End-user Video Quality Through Error Concealment and Packet Importance Modeling written by Yueh-Lun Chang and published by . This book was released on 2014 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: During video transmission, congestion and distortion in the network will cause packet loss on the video content and degrade the video quality. Traditionally the degradation is measured by mean-squared error or peak-signal-to-noise-ratio. However, these measurements do not correlate well with human perception. In this dissertation, we aim to improve the visual quality for end-users through packet importance modeling and error concealment. The visual impact to end-users differs based on the type of the packet losses. We aim to predict how end-users respond to different losses. We start with an objective experiment in which Video Quality Metric scores are computed on fixed-sized IP packet losses for H.264/AVC SDTV video, and then construct a network-based model to predict these scores. We would like to further understand the real visual impact on the perceptual quality, so we conduct a human subjective experiment on whole frame losses concealed by different decoders. Whole B frame losses are introduced in H.264/AVC videos which are then decoded by two different decoders with different common concealment methods: frame copy and frame interpolation. The videos are seen by human observers who respond to each glitch they spot. It shows that even when there are more lost bits for a whole frame loss than a slice loss, the overall perceptual quality is often actually better due to the concealment that gives observers less spatial misalignment. We develop network-based models which can predict the visibility of whole frame losses. Based on the estimated visual importance, we can prioritize packets in lossy networks. The models are deployed in intermediate routers to prioritize video packets and perform intelligent frame dropping to relieve network congestion. Dropping frames based on their visual scores proves significantly superior to random dropping of B frames. Another key solution to reduce the visual impact of video packet losses is effective error concealment methods and thus this is another focus in this dissertation. Here we work on both traditional 2D video and 3D stereo video. Among formats that provide stereo effect, 2D+depth encoding for stereoscopic video is one of the most compatible with current video content transmission systems. Traditionally the 2D and depth streams are independently coded, transmitted and concealed separately if delivered through lossy networks. We propose a new encoding scheme that offsets the I frame between the 2D and depth sequences. When a loss happens in either one, they could be concealed by the information from the other, using the strong motion correlation. Besides providing error concealment by postprocessing at the end-user side, enhancing the error robustness of video from the encoder side is another approach. We propose an end-to-end distortion model for rate-distortion optimized coding mode selection of 2D+depth bitstreams. In our work, we first extend the encoding mode, adding an extra motion information sharing mode for the depth stream, and then improve the concealment methods. Based on these changes, we use the proposed end-to-end distortion model and derive a new Lagrange multiplier for rate-distortion optimized 2D+depth mode selection in packet-loss environments by taking account of the network conditions, i.e. the packet loss rate. Other than the stereo video format, a new video coding technology "High Efficiency Video Coding (HEVC)" has also been standardized in 2013. While achieving 50% bitrate reduction compared to prior standards with equal perceptual video quality, HEVC is more sensitive to packet losses since each bit contains more information. To alleviate this problem, we propose a motion-compensated error concealment method for HEVC and implement the method in reference software HM. The motion vector from the co-located block will be refined for motion compensation. Based on the reliability of these motion vectors (MVs), blocks will be merged and assigned new MVs. Our experimental result shows that not only the subjective visual quality performs well but also there is a substantial PSNR gain.
Download or read book Mobile Telemedicine written by Yang Xiao and published by CRC Press. This book was released on 2008-06-03 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in the area of wireless and mobile telemedicine to diagnose and treat patients have drawn growing attention from healthcare providers and recipients, industry, researchers, and governments.This volumeexamines computing and network dilemmas which arise from wireless and mobile telemedicine. Comprised of the contributions of many prominent international researchers, the book gives an overview of patient care and monitoring, discusses the use of telemedicine in cardiology and diabetes, analyzes security and privacy considerations, examines issues relating to networking support, and concludes with a section on the opportunities and challenges that are faced by those involved in this exciting technology.
Download or read book Journal of Zhejiang University written by and published by . This book was released on 2006 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rate-Distortion Based Video Compression by : Guido M. Schuster
Download or read book Rate-Distortion Based Video Compression written by Guido M. Schuster and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most intriguing problems in video processing is the removal of the redundancy or the compression of a video signal. There are a large number of applications which depend on video compression. Data compression represents the enabling technology behind the multimedia and digital television revolution. In motion compensated lossy video compression the original video sequence is first split into three new sources of information, segmentation, motion and residual error. These three information sources are then quantized, leading to a reduced rate for their representation but also to a distorted reconstructed video sequence. After the decomposition of the original source into segmentation, mo tion and residual error information is decided, the key remaining problem is the allocation of the available bits into these three sources of information. In this monograph a theory is developed which provides a solution to this fundamental bit allocation problem. It can be applied to all quad-tree-based motion com pensated video coders which use a first order differential pulse code modulation (DPCM) scheme for the encoding of the displacement vector field (DVF) and a block-based transform scheme for the encoding of the displaced frame differ ence (DFD). An optimal motion estimator which results in the smallest DFD energy for a given bit rate for the encoding of the DVF is also a result of this theory. Such a motion estimator is used to formulate a motion compensated interpolation scheme which incorporates a global smoothness constraint for the DVF.
Book Synopsis Adaptive Frame Based Flexible Macroblock Ordering for Error Resilient H.264 Video Coding and Transmission by :
Download or read book Adaptive Frame Based Flexible Macroblock Ordering for Error Resilient H.264 Video Coding and Transmission written by and published by . This book was released on 2010 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transmission of video signal over wireless environments is becoming more common today as advances of telecommunication and multimedia convergence market make it possible. This enables the seamless mobile multimedia applications such as mobile video class and wireless video streaming. However, to achieve good video quality from such transmissions is still a challenging issue for practical video applications. This is due to the high error prone characteristic of wireless channels due to multipath effects and deep fades. Thus, research approaches to combat channel errors for better video quality especially error resilience video coding are one of the key research topics nowadays. In this dissertation, we propose two methods for error resilient in wireless video coding based on adaptive flexible macroblock ordering (FMO) for wireless video streaming applications. In the first method, effect of error propagation between frames is used as an indicator to generate FMO map frame-by-frame. A technique for generating FMO map is proposed to adapt with predicted error bursts of channel. In addition, a suitable intra refresh rate is selected to reduce the effect of error propagation. Therefore, the number of undecodable important macroblocks (MBs) is decreased. In the second method, we investigate the cross-layer approach between Application and Media Access Control (MAC) layers. In traditional approaches, video packets are classified and mapped into queues with different priorities at MAC layer. However, these approaches cause the unnecessary dropping packet at low priority queues. In the proposed approach, FMO map for each frame is generated by adaptive FMO and queuing overflow rate. Based on the estimated queuing overflow state information at the MAC layer, encoder maps MBs into slice groups in such a way that the arrival rate of packets to the full queue is reduced and arrival rate of packets to empty queue is increased. Hence, the number of dropped packet at Mac layer is minimized. The results in experiments showed that the proposed methods gain an improvement in terms of peak signal-to-noise rate (PSNR), number of undecodable MBs and number of dropped packets as compared to the previously proposed methods. The contributions gained from this dissertation would benefit the video communication community in future adoption of technology in practical wireless video transmission applications.
Book Synopsis Error Resilient H.264 Video Encoder with Lagrange Multiplier Optimization Based on Channel Situation by : Jian Feng
Download or read book Error Resilient H.264 Video Encoder with Lagrange Multiplier Optimization Based on Channel Situation written by Jian Feng and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Error Resilient H.264 Video Encoder with Lagrange Multiplier Optimization Based on Channel Situation.
Book Synopsis Rate-distortion Optimized Coding and Transmission of Compressed Video Streams Over Packet Networks by : Enrico Masala (ingegnere)
Download or read book Rate-distortion Optimized Coding and Transmission of Compressed Video Streams Over Packet Networks written by Enrico Masala (ingegnere) and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Smart Slice Prioritization in H.264 AVC by : Soumya Kannepalli
Download or read book Smart Slice Prioritization in H.264 AVC written by Soumya Kannepalli and published by . This book was released on 2011 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments in the fields of wireless communication and video compression have made it feasible to transmit video over wireless networks. However, due to the explosive volume of data, limited bandwidth and lossy channels, the transmitted video packets are corrupted which results in packet erasures. Considering that the network is unaware of the transmitted content, packet erasures during transmission can cause significant degradation in applications such as video streaming. The H.264/AVC standard supports valuable error resiliency tools to cope with packet erasures. In this thesis, I have designed two packet prioritization schemes to transport H.264 video streams over lossy networks. The objective of this research is to efficiently exploit the error-resiliency features of H.264 like Flexible Macroblock Ordering (FMO) and slice structure to design two priority schemes based on the importance of macroblocks or slices. Adaptive classification of macroblocks into slice groups is based on a variation of H.264/AVC checker board pattern and Cumulative Mean Square Error (CMSE) of a macroblock. The algorithm uses a two-phase system. In the first phase, the importance of every macroblock is calculated based on its influence on the current frame and future frames. In the second phase, the macroblocks with the highest priority are grouped together in separate slice groups using the FMO feature of H.264/AVC. An effective Unequal Error Protection (UEP) scheme using Rate Compatible Punctured Convolution (RCPC) codes as Forward Error Correction (FEC) tool to H.264/AVC output streams is employed to test the performance of prioritization. The second prioritization scheme is based on slice level priority assignment. H.264 slices contribute to different levels of video quality degradation due to channel errors. It is also widely known that slice losses have different visual impact on the video. That is, some losses last a single frame while others last till the end of Group of Pictures (GOP). Consequently, we consider the problem of calculating the packet loss visibility for pre-encoded video over wireless networks using CMSE as a metric to evaluate the video quality. A comparative analysis of the two proposed schemes is also carried out. It is observed that both schemes perform better than traditional approaches.
Book Synopsis Cross-layer Schemes for Enhancing H.264/AVC Video Quality Over Wireless Channels by :
Download or read book Cross-layer Schemes for Enhancing H.264/AVC Video Quality Over Wireless Channels written by and published by . This book was released on 2016 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid growth of video applications over wireless networks is overwhelming the wireless bandwidth. Since video applications demand large bandwidth and realtime transmission, supporting the rapidly increasing video traffic over the bandwidth-limited, error-prone, and time-varying wireless channels is very challenging. As a result, the video applications are likely to suffer packet losses over wireless networks which results in quality degradation. In this dissertation, we design a distortion prediction model for H.264/AVC compressed video streams, and use it for designing novel cross-layer protocols for enhancing the video quality by making more efficient use of the available wireless resources. The cumulative mean squared error (CMSE) is a widely used measure of video distortion. However, CMSE measurement is a time-consuming and computationally-intensive process which is not suitable for many video applications. A low-complexity and low-delay generalized linear model is proposed for predicting CMSE contributed by the loss of H.264 AVC encoded video slices. The model is trained over a video database by using a combination of video factors that are extracted during the encoding of the current frame, without using any data from future frames in the group of pictures (GOP). The slices are then prioritized within a GOP based on their predicted CMSE values. The accuracy of the CMSE prediction model is analyzed using cross-validation, analysis of variance, and correlation coefficients. The simulations are carried out to evaluate the performance of the CMSE prediction model for varying encoder configurations and bit rates of test videos. The CMSE slice prediction model is used to design an unequal error protection (UEP) scheme, using the rate-compatible punctured convolutional (RCPC) codes over wireless channels. This scheme provides protection to the video slices against the channel errors, based on their priority, in order to minimize the video distortion. An application of our slice prioritization is demonstrated by implementing a priority-aware slice discard scheme, where the low-priority slices are dropped from the router when the network experiences congestion. Additionally, the GOP-level slice prioritization is extended to the frame-level slice prioritization, and its performance is evaluated over the additive white Gaussian noise (AWGN) channels The idea of using slice CMSE prediction is extended to adapt the video packet size to the wireless channel conditions, in order to minimize the video distortion. A real-time, priority-aware joint packet fragmentation and error protection scheme for real-time video transmission over Rayleigh fading channels is presented. The fragment error rates (FERs) are simulated for a combination of different fragment sizes and RCPC code rates. These FERs are then used to determine the optimal fragment sizes and code rates for packets of each priority class by minimizing the expected normalized predicted CMSE per GOP in H.264 video bit stream. An improvement in the received video quality over the conventional and priority-agnostic packet fragmentation schemes is observed. Next, a cross-layer, priority-aware scheduling scheme for real-time transmission of multiple video applications over a time-varying channel is developed. Each video application considered has different characteristics such as user priority, latency, distortion, size, and encoding bit rate. A cost function is optimized to determine the scheduling order for video frames. The performance of our scheme is compared with that of the CMSE based scheme, where the frames are rank-ordered for transmission using its CMSE per bit values, and with the earliest deadline first (EDF) scheme in which each user takes turns to transmit a frame. A collaborative effort with other researchers and developed two additional cross-layer error protection schemes. In the first scheme, a cross layer UEP scheme that jointly assigned FEC at both the Application layer (using Luby Transform) and the Physical layer (using RCPC codes) for prioritized video transmission is developed. The video distortion function is minimized by using the genetic algorithm (GA). The performance of our scheme is evaluated for different channel SNR values. In the second UEP scheme, a framework that combined the RCPC codes and concatenated it with hierarchical quadrature amplitude modulation (QAM) is investigated. Employing RCPC codes and hierarchical modulation jointly resulted in greater flexibility as some parts of the data can be protected only by the hierarchical modulation while others may be protected by a low FEC code rate. The performance of the proposed scheme is compared to the standard 8-QAM with symmetric constellation.
