Recording spatial audio signals for interactive broadcast systems

Spatial audio processing is a key feature of the European funded FascinatE project. The FascinatE project will develop a system to allow end-users to interactively navigate and view around an ultra-high resolution video panorama showing a live event, with the accompanying audio automatically changing to match the selected view. The output will be adapted to their particular kind of device, covering anything from a mobile handset to an immersive panoramic display. The audio part of this project makes a spatial sound description available to the user. The facilitated technologies include Higher Order Ambisonics as well as Wave Field Synthesis. For Ambisonics, sound field information is recorded using microphone arrays like the SoundField microphone for first order signals or the Eigenmike for Higher Order Ambisonics representations. A Premier League match at the Stamford Bridge, London, was captured to provide audio-visual content form a live event. For the audio recording a number of standard microphones, shotguns, a SoundField microphone, and an Eigenmike were used. This contribution addresses the signal processing theory as well as practical aspects of spatial audio recordings. The theoretical part includes the processing of Higher Order Ambisonics signals for signal manipulation and adaptation to the visual content, as well as the detection of sound events from shotgun microphones for Wave Field Synthesis processing. The practical part covers the positioning of the microphones, noise problems and a basic rating of the recorded signals