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— We present a new cross-layer ARQ algorithm for video streaming over 802.11 wireless networks. The algorithm combines application–level information about the perceptual and temporal importance of each packet into a single priority value, which drives packet selection at each retransmission opportunity. Hence, only the most most perceptually important(More)
—The H.264/SVC video codec extends the H.264/AVC standard with scalability features. In this paper we introduce a traffic prioritization algorithm suitable for the transmission of both H.264/SVC and H.264/AVC video over 802.11e ad hoc wireless networks. The proposed algorithm exploits the traffic prioritization capabilities offered by 802.11e to provide(More)
The paper aims at evaluating a number of Quality of Service (QoS) indices of a real-time video transmission over an 802.11 ad hoc wireless network. Video is coded according to the state-of-the-art ITU-T H.264 encoder and its transmission is simulated by means of the ns network simulator. Objective quality measurements are presented. Moreover, the impact of(More)
Recommended by Zhu Han This work presents an application-level perceptual ARQ algorithm for video streaming over 802.11e wireless networks. A simple and effective formula is proposed to combine the perceptual and temporal importance of each packet into a single priority value, which is then used to drive the packet-selection process at each retransmission(More)
Porto, the institutional repository of the Politecnico di Torino, is provided by the University Library and the IT-Services. The aim is to enable open access to all the world. Please share with us how this access benefits you. Your story matters. Abstract—This work addresses the implications of using the Time-Division Unbalanced Carrier Sense Multiple(More)
— A new ARQ algorithm for video streaming over 802.11 wireless networks is presented. The algorithm operates at the application level in order to exploit information about the perceptual and temporal importance of each packet. A priority value is associated to each packet to determine which one to retransmit at each retransmis-sion opportunity. With respect(More)
— This paper evaluates the performance of video streaming in inter-vehicular environments using the 802.11 ad hoc network protocol. We performed transmission experiments while driving two cars equipped with 802.11b standard devices in urban and highway scenarios. Different sequences, bitrates and packetization policies have been tested. The experiments show(More)
This paper presents an analysis-by-synthesis technique to evaluate the perceptual importance of multimedia packets for rate-distortion optimized streaming. The proposed technique, instead of relying on a priori information, computes the distortion that would be caused by the loss of each single packet, including the effects of error propagation and(More)
We present a new algorithm to dynamically identify perceptually important regions in pictures of a video sequence. For each macroblock, the distortion that its loss would cause at the decoder is computed. High-distortion macroblocks are then grouped together into slices to be protected with forward error correction or to be sent as " premium " packets. We(More)
— We present a new ARQ algorithm for video streaming over wireless channels. The algorithm takes into account the perceptual and temporal importance of each packet to determine the packet scheduling which maximizes the perceived quality. We propose a simple and flexible function to combine the perceptual importance with the real-time constraints of each(More)