Juan Carlos De Martin

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Mobile multimedia applications, the focus of many forthcoming wireless services, increasingly demand low-power techniques implementing content protection and customer privacy. In this paper low complexity perception-based partial encryption schemes for speech are presented. Speech compressed by a widely-used speech coding algorithm, the ITU-T G.729 standard(More)
We present a source-driven approach to packet marking for speech transmission over packet networks implementing the Differentiated Services model. Packets generated by the speech coder are examined: if deemed perceptually critical, they are marked as premium and sent on a “virtual wire;” otherwise, they are sent as regular best-effort traffic. Applied to(More)
Despite the great interest towards long term recordings of Electromyographic (EMG) signals, which find applications for example in telemedicine, only a few studies have dealt with compression of these signals. In this paper we propose a lossy coding technique for surface EMG signals. The technique is based on the Linear Predictive Coding paradigm widely(More)
This paper presents simulation results outlining the behavior of rate-adaptive voice communications over IP networks. In the considered architecture, voice coders adapt their rate to the current state of the network, so as to generate only the bandwidth that the network is capable of carrying. An algorithm is proposed for driving the transmission rate of(More)
The popularity of DASH streaming is rapidly increasing and a number of commercial streaming services are adopting this new standard. While the benefits of building streaming services on top of the HTTP protocol are clear, further work is still necessary to evaluate and enhance the system performance from the perspective of the end user. Here we present a(More)
We present an adaptive technique to transmit speech over 802.11 wireless packet networks. According to the proposed scheme, the speech coding rate of a network-driven variable bitrate coder is selected to match the istantaneous wireless channel conditions: higher rates (i.e., larger packets) for low error rates, lower rates (i.e., smaller packets) when the(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)
A new form of telephony is being made possible by the nearly-ubiquitous presence of 802.1 1 wireless local networks (WLAN’s). This paper presents a technique to improve speech quality for WLAN telephony. Speech compressed by the 3GPP GSM AMR coding standard at 12.2 kbls is packetized and classified according to an analysis-by-synthesis estimate of the(More)
In this paper we consider the problem of lossless compression of video sequences exploiting the temporal redundancy between frames. In particular, we present a technique performing motion compensation on more than one past frame. Each prediction component is optimally weighted to minimize the mean squared error of the residual. Experimental results for(More)
| Today’s packet networks including the Internet offer an intrinsic diversity for media distribution in terms of available network paths and servers or information sources. Novel communication infrastructures such as ad hoc or wireless mesh networks use network diversity to extend their reach at low cost. Diversity can bring interesting benefits in(More)