Video Transmission

... 5: Scalable Video Coding (in integrated form with ITU-T Rec. H.264 | ISO/IEC 14996-10). JointVideo Team (JVT), Doc. JVT-R201, Jan. 2006. 4. Luby, M., Stockhammer, T., Watson, M., Gasiba, T., and Xu, W. Raptor Codes for Reliable Download Delivery in Wireless Broadcast ...

With the rapid development of the application of video surveillance and broadcast systems, the evaluation of video quality becomes an emerging research. Error detection is an important criterion to measure the quality of images/videos transmitted over unreliable networks particularly in the wireless channel. At the time of acquisition and transmission, video frames are always distorted by various artifacts. In
many video processing applications, accurate knowledge of these errors or distortions present in the input video sequence is very important. In a real system, noises are mainly introduced by the camera and the quantization step of decoding process. But the distortions occur when the videos are transmitted through analog or digital medium. Some errors may be introduced when the analog video signal transmits
in wired channel, but in wireless communication it cannot be ignored as occurring frequently. So, structure-oriented video distortions detection significantly impacts the effectiveness of video processing algorithms.

Through the advancement of IPTV and HDTV technology, previously subtle errors in videos are now becoming more prominent because of the both structure oriented and compression based artifacts. To transmit high quality videos and images with low bit rate over the wireless channel, various compression algorithms are used. In B-DCT compression a slight change of luminance in border area can cause a step in the decoded image if the neighbor block fall into different quantization intervals. Therefore, the decompressed image and video exhibits various kind of artifacts. One of the most obtrusive artifacts is the ”Blocking Artifact”. Both compression and content based error occurs not only in video broadcasting but also surveillance systems during its transmission over wired and wireless channel.

In this dissertation, we focus towards the development of a real-time video quality check system.To overcome the above issues we first propose a measurement system for compression based and broadcasted artifacts and then analyze the distortion patterns occurred during broadcasting over wireless channels.

Firstly, The proposed system is achieved by a measurement of various artifacts of videos by analyzing the distribution of local properties of image signals like dominant edge magnitude and direction. We also propose a metric to detect damaged frame by considering the contextual information, such as their consistency and edge continuity.
To achieve human vision measurement system we incorporate light weighted edge gradient magnitude information for video artifacts. According to the statistical information the distorted frames are then estimated based on the characteristics of their surrounding frames. Then we generate a criteria function to detect the distorted frame from sequence of video frames.

Secondly, we propose a method to analyze the distortion pattern or block errors in video frames that occurred during its transmission and broadcasting over wireless channel. To achieve real-time performance we quantize edge gradient phase information of the image and  histogram of the quantized values. By making the noise characteristics, we can filter out background pixels and compression based patterns.
Then use the prominent texture patterns to classify them in different block errors and analyze them for error concealment. So, through  accumulating histogram-based edge gradient information we can achieve height, width, shape and rotation of the distortion patterns of the video frames and analyze the distorted content pattern not only in video error detection application but also in error concealment, restoration
and retrieval.

Finally, evaluating the performance of all the mechanisms through extensive experiments on prominent datasets and broadcasted videos show that the proposed algorithm is very much efficient to detect errors for video broadcast and surveillance applications in terms of computation time and analysis of distorted frames.

This paper analyses the possibility of exploiting a small spacecrafts constellation around Mars to ensure a complete and continuous coverage of the planet, for the purpose of supporting future human and robotic operations and taking advantage of optical transmission techniques. The study foresees such a communications mission to be implemented at least after 2020 and a high data-rate requirement is imposed for the return of huge scientific data from massive robotic exploration or to allow video transmissions from a possible human outpost.In addition, the set-up of a communication constellation around Mars would give the opportunity of exploiting this multi-platform infrastructure to perform network science, that would largely increase our knowledge of the planet.The paper covers all technical aspects of a feasibility study performed for the primary communications mission. Results are presented for the system trade-offs, including communication architecture, constellation configuration and transfer strategy, and the mission analysis optimization, performed through the application of a multi-objective genetic algorithm to two models of increasing difficulty for the low-thrust trajectory definition.The resulting communication architecture is quite complex and includes six 530 kg spacecrafts on two different orbital planes, plus one redundant unit per plane, that ensure complete coverage of the planet’s surface; communications between the satellites and Earth are achieved through optical links, that allow lower mass and power consumption with respect to traditional radio-frequency technology, while inter-satellite links and spacecrafts-to-Mars connections are ensured by radio transmissions. The resulting data-rates for Earth–Mars uplink and downlink, satellite-to-satellite and satellite-to-surface are respectively 13.7 Mbps, 10.2 Mbps, 4.8 Mbps and 4.3 Mbps, in worst-case.Two electric propulsion modules are foreseen, to be placed on a C3∼0 escape orbit with two Zenith Sea Launch rockets in March 2021 and carrying four satellites each. After the entrance in Mars sphere of influence, the single spacecrafts separate and spiral-down with Hall effect thrusters until they reach the final operational orbits in April 2025, at 17,030 km of altitude and 37 deg of inclination. The preliminary design includes 105 kg and 577 W of mass and power margin for each satellite, that can be allocated for scientific payloads.The main challenges of the proposed design are represented by the optical technology development and the connected strict pointing constraints satisfaction, as well as by the Martian constellation operations management.This mission study has therefore shown the possibility of deploying an effective communication infrastructure in Mars orbit employing a small amount of the resources needed for the human exploration programme, additionally providing the chance of performing important scientific research either from orbit or with a network of small rovers carried on-board and deployed on the surface.

The explosion of video generation and consumption, coupled with an inadequate rise in network bandwidth has led to network delays and decreased Quality of Experience, limiting the opportunities to tap into the full potential of video data. These deficiencies in network resources with a shift to cloud computing models have resulted in the need to revisit the overall mechanism for video transfer and storage of videos between edge devices and the cloud. We propose a novel multi-scale real-time super-resolution convolutional neural network to achieve the composite task of optimizing the entire cost of video transfer with minimal loss of quality that can be used for any application involving the transfer of video data. To achieve this, we develop a cost-optimized video transfer system that optimizes the metrics of video transfer to give the best quality video output, given the user budget. The model makes use of Convolution blocks for extracting features and output creation with multiple sub-pixel convolutions in a novel structure. For upscaling to full High Definition video at 30 fps, the model successfully retained the frame rate while the system achieved savings in transfer time and bandwidth usage. This model has been trained on surveillance videos (VIRAT dataset), but consistent results were obtained during testing even on feature films and sports videos which demonstrates its content invariance. The evaluation of our approach averaged over 376 videos, yielded meager quality losses of 8%, measured by a novel non-referential quality metric, also proposed in this pa- per. Additionally, average network bandwidth savings of 80% and average video transfer time reduction of 52% were achieved.

Craters, ridges and rocks are the features to be extracted in the lunar images. Proposed methodology deals with detection of linear feature such as (i) ridges, (ii) lineaments and (iii) nonlinear features like craters. All edges are identified as either crater or lineament. Therefore, all circular edges are recognized as craters edges, and those remained edges, which are not crater edges and low possibility of the noise, are recognized as lineaments in the remained edges. The Steps for lineament recognition includes the steps such as Crater Rim Elimination, Small Area Elimination and Lineament Classification. Ridges detection includes edge extraction using haar wavelet transform followed by morphological operations such as dilation and erosion. For detection of non linear features such as craters, the most predominant feature on the lunar terrain, circular hough transform is used. But it fails to detect craters without proper connected edges because of presence of shadows in an image. This paper includes algorithms for shadow removal in the images which accounts for changes in illumination, visual appearance, and size. Results indicate that the detection rate is improved with shadow removal techniques.

In this paper a novel approach for de noising images corrupted by random valued impulses has been proposed. Noise suppression is done in two steps. The detection of noisy pixels is done using all neighbor directional weighted pixels (ANDWP) in the 5 x 5 window. The filtering scheme is based on minimum variance of the four directional pixels. In this approach, relatively recent category of stochastic global optimization technique i.e., particle swarm optimization (PSO) has also been used for searching the parameters of detection and filtering operators required for optimal performance. Results obtained shows better de noising and preservation of fine details for highly corrupted images.

Abstract: In this report, the DVB-H channel is studied for its capabilities to transmit stereo video in different formats and to provide adequate,error protection for such content. The following stereo video representations are considered: two channel stereo, encoded either independently with H.264 encoder (simulcast) or by multi-view coding (MVC) and video plus depth both encoded,by H.264. These encoding approaches are

Degradation of network performance during video transmission may lead to disturbing visual artifacts. Some packets might be lost, corrupted or delayed, making it impossible to properly decode the video data on time at the receiver. The quality of the error-concealment technique, as well as the spatial and temporal position of the artifacts have a large impact on the perceived quality after decoding. In this paper, we use the spatial scalability feature of Scalable Video Coding (SVC) for error-concealment. This enables the transmission of a lower resolution video with a higher robustness, for example using unequal error protection. Under the assumption that only the higher resolution video would be affected, we evaluated the visual impact of packet losses in a large scale subjective video quality experiment using the Absolute Category Rating method. The number of impairments, the duration, and the interval between impairments as well the quality of the encoded lower resolution video are varied in a systematic evaluation. This allows for analyzing the influence of each factor both independently and jointly.

Delay-sensitive video transmission over IEEE 802.11 wireless local area networks (WLANs) is analyzed in a cross-layer optimization framework. The effect of delay constraint on the quality of received packets is studied by analyzing “expired-time packet discard rate”. Three analytical models are examined and it is shown that M/M/1 model is quite an adequate model for analyzing delay-limited applications such as

Current Web based systems are designed for the static class of document based information. In the next generation of information systems, digital video will form an important class of traffic. Emerging systems will need to handle multimedia applications that possess varying traffic charac-teristics and have Quality-of-Service (QoS) requirements in terms of bounded delay, jitter, loss rate, synchronization skew etc.[13]. In order to design and deploy these complex and evolving systems with proper cost/performance ratios, we must ...

— The fifth generation (5G) wireless networks are predictable to achieve 1000 times higher capacity contrasted to the fourth generation (4G) wireless networks. Hence, the improvement of spectrum efficiency (SE) is an important problem, which must be considered. Noticeably, Cognitive radio (CR) is as an efficient methodology to minimize the spectrum scarcity problem. The goal of the paper is to enhance the throughput efficiency of data transmission and reduces the delay in wireless Adhoc networks. The users are categorized into Licensed Primary Users and Unlicensed Secondary Users in the Cognitive Radio Networks (CRN) and there is no dedicated channel to send information, sensors are need to consult with the neighbors and picking up a channel for data transmission in CR-WSNs. If the PU claims the channel, the SUs have to run off from the channel without delay. As a result, data channels should be chosen intelligently by considering the behavior of PU's on the channel and using some Priority Based Selection algorithms. So, here our proposed cognitive radio method helps to automatically search the users those who are free to communicate on the network, at that time Unlicensed user is automatically will change as licensed user, then it communicate in particular person. Additionally, we proposed the Resource management technique is used to reduce the delay during video streaming. For that resource management of the spectrum, Distributed Real Time Management algorithm (DRTMAL) is introduced with multi-agent learning. We used two protocols called DSR and MCRP to compare with proposed technique and shows the DRTMAL algorithm is the best resource management method for video streaming through OFDMA in Cognitive radio networks.

This paper studies an application of turbo codes to compressed image/video transmission and presents an approach to improving error control performance through joint channel and source decoding (JCSD). The proposed approach to JCSD includes error-free source information feedback, error-detected source information feedback, and the use of channel soft values (CSV) for source signal postprocessing. These feedback schemes are based on a modification of the extrinsic information passed between the constituent maximum a posteriori probability (MAP) decoders in a turbo decoder. The modification is made according to the source information obtained from the source signal processor. The CSVs are considered as reliability information on the hard decisions and are further used for error recovery in the reconstructed signals. Applications of this joint decoding technique to different visual source coding schemes, such as spatial vector quantization, JPEG coding, and MPEG coding, are examined. Experimental results show that up to 0.6 dB of channel SNR reduction can be achieved by the joint decoder without increasing computational cost for various channel coding rates.

This paper reports on activities in Study Group 12
of the International Telecommunication Union (ITU-T SG12) to
define a new Recommendation on subjective evaluation methods
for gaming Quality of Experience (QoE). It first resumes the
structure and content of the current draft which has been
proposed to ITU-T SG12 in September 2014 and then critically
discusses potential gaming content and evaluation methods for
inclusion into the upcoming Recommendation. The aim is to start
a discussion amongst experts on potential evaluation methods
and their limitations, before finalizing a Recommendation. Such
a recommendation might in the end be applied by non-expert
users, hence wrong decisions in the evaluation design could
negatively affect gaming QoE throughout the evaluation.

Handoff in a distributed IEEE 802.11 Wireless LAN network is a source of significant amount of problems on the video transmission environment. The visual quality of video streaming applications is lowered when stations are in handoff status. In this paper we introduce an architecture of a session proxy (SP), which tries to preserve the quality of the streaming video upon each handoff between access points. We have evaluated thresholds of RSSI and Loss Frame Rate (LFR) for deciding the moment when the handoff process shall begin. Our solution performance was evaluated in a testbed implementation for MPEG-4 video-on-demand with one video server (VLS) and two FreeBSD based access points supporting Mobile IP, DHCP Server and IAPP approach.

This paper proposes a channel error adaptive FEC algorithm to balance the conflict between the QoS of video transmission and the bandwidth utilization ratio in wireless IP networks. Two analytic models are derived, one is playable frame rate in MPEG video stream, another is effective utilization ratio of FEC. Based on these analytic models, quality of video stream and effective utilization ratio of FEC under different network conditions (presented by packet loss probability in this paper) are predicted. Then optimal amount of redundant packets is calculated and decided, which makes both the quality of video stream and the effective utilization ratio of FEC approximate their maximum. The simulation results show that the proposed algorithm improves system performance in both the QoS of wireless video transmission and the utilization of bandwidth.

The increase of IEEE 802.11's bandwidth led to a deployment of many multimedia applications over wireless networks. Nevertheless, these applications impose rigorous discipline constraints in QoS. To support the varying Quality-of-Service (QoS) requirements of emerging applications, the QoS-capable standard IEEE 802.11e has been specified. Digital video delivered over wired-to-wireless networks is expected to suffer quality degradation from packet loss. Video traffic is widely expected to account for a large portion of the traffic in future hybrid network, as multimedia applications are becoming increasingly popular. Initially this paper attempted to discover optimal parameters such as bandwidth utilization and packet size in order to enhance video stream quality and proposed New Adaptive Crosslayer Algorithm, a novel scheme for QoS enhancement for IEEE 802.11 wireless networks.