For the ninth edition of ImageSanté, a festival devoted to health held in Liège, the organisers wanted to transmit audio and images of brain surgery carried out at Liège University Hospital to the Sauvenière cinema theatre, 10 miles away. The aim was for spectators in the cinema to be able to interact live and direct with the neurosurgeon during the operation. This was achieved via a duplex audio system linking the two sites. Images were transmitted and projected in 3D stereo and full HD quality – the project was a collaboration between 16 companies, the university and the audiovisual and multimedia technology network from the Belgian French-speaking community.
The management of the projection and the transmission of the audio links were designed and supervised by Pierre Audrit of consultant bureau Acqi. As an independent quality controller, Audrit became involved in the installation of early digital cinema installations in Belgium.
“Capturing images in an operating theatre is not easy,” said Audrit. “Nor is getting that footage live and in 3D stereo full HD into a cinema. The company IntoPIX provided the solution for the retransmission of the images in JPEG 2000 standard over an optical fibre network with a 1Gbit capacity for projection in the fully booked 300-seater cinema.”
The big challenge for the audio part of the installation was avoiding delay in the duplex audio communications between the hospital and the theatre. “The audio signal was embedded and synchronised in the image stream, but the transmission caused a delay of some seconds between the live and the projected image,” Audrit explains. “This caused problems during the interaction with the public in the cinema and made dialogue with the surgeon quite difficult. Sofico supplied three pairs of fibre optic cables, specially dedicated to the project, offering a continuous glass conduit between the hospital and the venue. We used fibre optics for the image, so the choice for the same carrier for audio was logical.”
Audrit says when it came to use the Audio over IP connectivity, MDOUK’s Audio TX STL-IP turned out to be the best solution. “The advantage was the extremely low delay – in combination with the Codec 7.20 we achieved excellent audio quality. In a parallel link via the Audio TX STL-IP we included a separate channel to allow dialogue between the engineers on both sites,” he explains. “We used the pre-configured machines and we plan for future 3D projects to continue using the MDOUK transmission.”
MDOUK Audio TX STL-IP is an easy-to-use, cost-effective solution for audio delivery over IP networks. It is said to offer the same quality with low delay as conventional circuits, but with the flexibility of using IP connectivity. For such a critical project MDOUK could deliver a high reliable solution for real-time audio distribution over IP.
It was rental company WNM that took on the technical installation of the audio link and the amplification in the cinema theatre by means of L-Acoustics cabinets. “We used DPA 4066 headsets (pictured) and Sennheiser SK 5212 and EM 3032-U receivers for all wireless transmissions in the hospital. To capture the ambience of the operating room in the hospital, we used Sennheiser MKH 416 tube microphones,” says Gaëtan Crenier, general manager of WNM.
“In the cinema, the presenter was equipped with a Sennheiser SKM 5200 and a Neumann KK 105 head with ‘command’ function (push-to-talk button on the microphone to remote audio outputs on the wireless receiver) plus a Sennheiser EM 3732-U receiver. We also used wireless ear-pieces from Phonak.”
“The transmission and the surgical operation – the removal of a brain tumour – have been a success. We didn’t [need to] use the extra ISDN connection installed as back-up,” concludes Audrit.