iMP » work package 4

iMP Audio Processing Papers

editor — Sat, 16 Jul 2011 16:05:21 +0000

iMP presents two novel works on audio processing, work carried out by Barcelona Media:

G. Cengarle, T. Mateos, D. Bonsi, A second order Ambisonic device using velocity transducers Accepted for publication as a regular paper in the Journal of the Audio Engineering Society.

Abstract: The relation between sound pressure gradient and air particle velocity is exploited to obtain second order spherical harmonics of the pressure field via velocity gradients. The existence of anemometric transducers capable of directly measuring the acoustic velocity field might therefore allow the construction of higher order Ambisonics microphones of very small size and accurate polar patterns. This possibility is simulated numerically and tested experimentally employing two Microflown pressure-velocity probes in a face to face configuration, validating the results through the analysis of the second order polar responses measured in anechoic conditions. To conclude, a proposal for the design of a three-dimensional second order device using the minimum number of transducers is presented.

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G. Cengarle, T. Mateos, Comparison of anemometric probe and tetrahedral microphones for sound intensity measurements Presented at the 130th AES Convention, London, May 2011.

Abstract: The measurement of sound intensity requires the acquisition of sound pressure and acoustic velocity in a coincident position. Various transducers topologies can be used to measure the acoustic velocity directly or indirectly. In this paper, three transducers are compared: a pressure-velocity anemometric probe and two tetrahedral B-Format microphones from different manufacturers. The comparison has been carried out in different fields, ranging from anechoic to diffuse, reverberant field conditions. The analysis and comparison is based on intensimetric quantities such as the radiation index and the sound intensity vector. Strengths and limitations of the various approaches are reported, to suggest the preferred application for each transducer.

D4.2.1 Algorithms and first version of creative applications for audio adaptation to 3D scenes

editor — Wed, 27 Jan 2010 15:00:53 +0000

This document describes the novel audible applications developed during the first 12 months of the project, and discusses how they integrate in the general iMP architecture and philosophy. The document is divided in three parts.

The first part describes the novel post-production tools for 3D soundtracks that make use of the metadatabase. This prototype allows to author soundtracks in 3D audio by giving the engineer the capability of linking audio tracks of an Audio Workstation to a 3D scene representation.

The second part describes the research done in algorithms capable of generating and filling some of the most important metadata of the metadatabase that are relevant to 3D audio post-production (i.e. realistic reverberations by inferring the room/scene from existing wet audio).

The third part discusses in detail the integration with the medatabase layer. Finally, we discuss future work that will be done in order to finalize the novel audible applications and integrate them into the “Virtual Film Factory”.

D4.3.1:Prototype of first enhanced existing application

admin — Mon, 11 Jan 2010 14:56:28 +0000

The conform process is an essential part of post production, and provides both an excellent test case for a metadatabase driven workflow and a basis for the development of the concept of the virtual film factory. A new conform prototype within the existing Baselight application was developed to explore the benefits and optimal architecture for a distributed metadatabase. A comparison with the current state-of-the-art shows the scope for parallelism in the new approach as well as the benefit of pre-processing metadata like the frame rate, derived from image file sequences rather than individual files, a calculation currently performed with considerable overhead. Many opportunities present themselves to exploit the vast performance improvements for enhancements of the non-linear finishing process as a whole, from late in-context decision making to more flexible versioning and a more interactive creative environment.

D4.1.2:Prototype versions of the browser/viewer tools

admin — Mon, 11 Jan 2010 14:55:17 +0000

The prototype version of a metadatabase driven browser/viewer is described, including its architecture within a distributed image server environment. Taking advantage of instant access to content metadata, the high i/o and processing bandwidth of the image and the wide scope for parallelism, it is possible to use the visual representation of lists of shots in a timeline or gallery as an effective tool to directly select, manage, review, compare and process the underlying content.This document needs to be read in conjunction with D3.2.1 (Initial API and Metadatabase Middleware Specification) and D4.3.1 (Prototype of first enhanced existing application) and seen with reference to D2.1.1(Scenarios and Requirements for postproduction, distribution and customization in a virtual film factory).

D4.1.1:First prototype of the graphic engine supporting the iMP architecture

admin — Mon, 29 Jun 2009 13:01:24 +0000

This deliverable presents an overview of the initial adaptation of UPF’s existing 3D graphics framework for use with the putative iMP architecture. The novel work for this deliverable centered on the creation of a system for real-time streaming of video sequences, stored in a local database, as textures to various objects within a 3D environment. The work in this deliverable was presented at ACM Advances in Computer Entertainment Technology (ACE) 2009, Athens, Greece. The deliverable consists of an introduction, some technical details about the implementation, and finally some screenshots.