Christian Lottermann

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We present a novel bit rate model for H.264/AVC video encoding which is based on the quantization parameter, the frame rate as well as temporal and spatial activity measures. With the proposed model, it is possible to trade-off the frame rate versus the quantization parameter to achieve a target bit rate. Our model depends on video activity measures that(More)
—We study the uplink delivery of live video using adaptive HTTP streaming (AHS). In AHS, the process of simultaneously creating video levels at different rates is computationally demanding and quickly exceeds the computational capacity of mobile devices. As a remedy, we propose a network-aware video level selection approach which reduces the number of(More)
We present a low complexity approach for the estimation of the temporal and spatial activity parameters of videos which are captured by a front-facing camera of a vehicle based on context information of the vehicle. The estimated parameters are integrated into an objective video quality metric, which can be used to determine the perceptual quality of a(More)
This paper presents the research and development activities within " SolarMesh-Energy-Efficient, Autonomous, Wide-Area Wireless Voice and Data Network " , a R&D project funded by the German Federal Ministry of Education and Research. The project, bringing together expertise from academia and industry in Germany, is specifically dedicated to develop reliable(More)
Emergency situations where lives are at stake, such as natural disasters, accidents, or serious fire, require low reaction times. Especially in sparsely populated areas the distance between the nearest emergency station and its disaster location may be quite large. In order to minimize reaction times, emergency communication is to be prioritized with(More)
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