Reducing the Latency in Live Music Transmission with the BeagleBoard xM Through Resampling

In previous works, a widespread embedded platform, the BeagleBoard xM, was shown to provide sufficient through-put and acceptable latency for live music control and audio signals transmission on standard LAN and WLAN protocols. Although the preliminary work opened the way for further investigations, the software stack did not prove efficient enough to deliver stable audio performance below the perceptual latency threshold for good ensemble playing. This work reports on a custom Debian Linux image, called WeMUST-OS for the BeagleBoard xM, configured for the task at hand by careful low-level ALSA driver configuration with the DM3730 SoC and the TPS65950 audio codec to improve local audio input/output latency. Furthermore Jacktrip, an application for music audio transmission, has been modified with added support to resampling enabling seamless connection with other devices running audio at different sample rate and period size. Leveraging these two achievements, latency is shown to keep under perceptual threshold for ensemble music performance including transmission of the monitoring signal

Clock skew compensation by adaptive resampling for audio networking

Wired Audio Networking is an established practice since years, based on both proprietary solutions or open hardware and protocols. One of the most cost-effective solutions is the use of a general purpose IEEE 802.3 infrastructure and personal computers running IP based protocols. One obvious shortcoming of such setup is the lack of synchronization at the audio level and the presence of a network delay affected by jitter. Two approaches to sustain a continuous audio flow are described, implemented by the authors in open source projects based on a relative and absolute time adaptive resampling. A description of the mechanisms is provided along with simulated and measured results, which show the validity of both approaches

Constraints for the evolution of the Gubbio fault zone: preliminary results from micro-structural analysis, fluid inclusions, cathodoluminescence and stable isotopes analyses

Serie Special

Deformation features within an active fault zone in carbonate rocks: The Gubbio fault (Central Apennines, Italy)

The Gubbio fault is an active normal fault defined by an important morphological scarp and normal fault focal mechanism solutions. This fault truncates the inherited Miocene Gubbio anticline and juxtaposes Mesozoic limestones in the footwall against Quaternary lacustrine deposits in the hanging wall. The offset is more than 2000 m of geological throw accumulated during a poly-phased history, as suggested by previous works, and has generated a complex zone of carbonate-rich fault-related structures. We report the results of a multidisciplinary study that integrates detailed outcrop and petrographic analysis of two well-exposed areas along the Gubbio fault zone, geochemical analysis (fluid inclusions, stable isotopes, and trace elements) of calcite-sealed fault-related structures and fault rocks, and biostratigraphic controls. Our aims are: (i) the characterization of the deformation features and their spatialetemporal relationships, and (ii) the determination of the P/T conditions and the fluid behaviour during deformation to achieve a better understanding of fluiderock interaction in fault zones. We show that few of the observed structures can be attributed to an inherited shortening phase while the most abundant structures and fault rocks are related to extensional tectonics. The outcropping extensional patterns formed at depths less than 2.5e3 km, in a confined fluid system isolated from meteoric water, and the fault structures are the response to a small amount of cumulated displacement, 12e19% of the total geological throw