Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 6 Articles
In this paper, we propose a new Scalable Video Coding (SVC) quality-adaptive peer-to-peer television (P2PTV) system executed\nat the peers and at the network. The quality adaptation mechanisms are developed as follows: on one hand, the Layer Level\nInitialization (LLI) is used for adapting the video quality with the static resources at the peers in order to avoid long startup times.On\nthe other hand, the Layer Level Adjustment (LLA) is invoked periodically to adjust the SVC layer to the fluctuation of the network\nconditions with the aim of predicting the possible stalls before their occurrence. Our results demonstrate that our mechanisms\nallow quickly adapting the video quality to various system changes while providing best Quality of Experience (QoE) that matches\ncurrent resources of the peer devices and instantaneous throughput available at the network state....
In transmitting video data securely over Video Sensor Networks (VSNs), since\nmobile handheld devices have limited resources in terms of processor clock speed and\nbattery size, it is necessary to develop an efficient method to encrypt video data to meet the\nincreasing demand for secure connections. Selective encryption methods can reduce the\namount of computation needed while satisfying high-level security requirements. This is\nachieved by selecting an important part of the video data and encrypting it. In this paper, to\nensure format compliance and security, we propose a special encryption method for\nH.264, which encrypts only the DC/ACs of I-macroblocks and the motion vectors of\nP-macroblocks. In particular, the proposed new selective encryption method exploits the\nerror propagation property in an H.264 decoder and improves the collective performance\nby analyzing the tradeoff between the visual security level and the processing speed\ncompared to typical selective encryption methods (i.e., I-frame, P-frame encryption, and\ncombined I-/P-frame encryption). Experimental results show that the proposed\nmethod can significantly reduce the encryption workload without any significant degradation\nof visual security....
This paper presents a new application of the\nIntegrated Services Digital Broadcasting - Terrestrial version B\n(ISDB-TB) digital television system to transmit data in the\nInternet Protocol (IP) format encapsulated in the MPEG-2\nTransport Stream (MPEG-2 TS). The use of this encapsulation\ntechnique ensures compatibility of the ISDB-TB multiplexing\nsystem, allowing the transmission of IP packets. The proposed\napplication is unidirectional, i.e., there is no return channel and\nthe protocol used in the IP packets is the User Datagram Protocol\n(UDP)....
This article is based on the assessment of the quality\nof video signals, specifically an objective evaluation of completely\nreferenced video signals in standard definition. The most reliable\nway to measure the difference in quality between two video\nscenes is using a panel made from television viewers, resulting in\na subjective measure of the difference in quality. This\nmethodology requires a long period and has an elevated\noperational cost; this makes it an unpractical method to be used.\nThis article will present the relevant aspects for the assessment of\nvideo application in standard definition digital television and the\nvalidation of these methodologies. The objective is to test metrics\nbelow the computational cost that evaluate the peak signal-to noise\nratio (PSNR) and measures the structural similarity index\nmeasure (SSIM). One methodology for the validation of these\nmetrics is presented and is based on the scenes and the results of\nsubjective tests performed by VQEG. The scenes for these\nmetrics are prepared by the equalization of brightness, detail\nsmoothing, and edge detection. Controlling the intensity of these\nfilters, a new set of measures is obtained. Performance\ncomparisons are made between these new sets of measures and\nthe set of measures obtained by VQEG. The results showed that\nthe objective measures are easily implemented from the\ncomputational point of view, and can be used to compare the\nquality of video signals, if properly combined with techniques for\nthe adequacy of the human visual system like the mitigation and\nextraction of contours....
This paper presents a simulation tool for the ISDBTB\nmodulator, to perform complex analyses in each processing\nstage. From a Broadcast Transport Stream (BTS) file you can\nfollow the processing performed in each modulator block to the\nfinal transmission stage. It is possible to make real transmissions\nwith the RF files generated in the simulator with the use of a\nvector signal generator. A mathematical and practical approach\nto the operation of each modulator block is performed starting\nwith the description of the BTS signal up to the final transmission\nstage....
This paper describes the preliminary test results of\nthe transmission and reception of Digital TV signals, on Channel\n41, in the metropolitan region of Curitiba, in the state of Paran�¡,\nBrazil. It describes the equipment configuration deployed to\ncarry out the tests, with the objective of mapping signal levels in\nthe field and carrying out objective (channel power received,\nC/N, MER) and subjective measures (signal quality and\nobservation of artifacts) in 200 selected locations in the\nmetropolitan region of Curitiba. A propagation model is\ndiscussed (based on the Log-distance and Okumura-Hata\nmodels), as a function of the received channel power values\nmeasured in some selected locations. The results should allow the\ncalculation of the coverage area, and the identification of the\nshadowed areas and critical reception points....
Loading....