WGBH, the public broadcaster in Boston, Mass and the leading producer for PBS, has installed a new Thomson mobile video transmission system from Grass Valley™, based on the ATSC A/153 standard. WGBH's mobile video service was launched in late 2009 with additional channels added in 2010.
In addition to its main HD DTV channel, the station is simulcasting two Mobile DTV channels: its primary signal plus the 'GBH Kids channel. WGBH is also rebroadcasting its radio services 89.7 WGBH and 99.5 All Classical in mobile as part of its 6 MHz of digital television spectrum.
"We're very excited to be the first in our market to offer Mobile DTV services to our audience. We see Mobile DTV as a way to expand our ability to deliver services such as our 99.5 All Classical to a broader geographic area on a wider range of devices", said Joe Igoe, Chief Technology Officer for WGBH. "Grass Valley's statistical multiplexing for Mobile DTV will allow us to offer more of our educational services at a higher quality level than would be otherwise possible in our broadcast spectrum. We plan to offer additional Mobile DTV services as the market develops."
As the only supplier in the broadcast industry to provide equipment from image capture through RF transmission, Grass Valley leveraged years of experience and a broad product portfolio to develop a complete ATSC Mobile DTV system that is fully integrated and pre-configured to ensure real-world success.
"Unlike standard ATSC Mobile DTV encoders, the ViBE line offers Scalable Video Coding and unique Region of Interest encoding algorithms that automatically detect the visually interesting area of a picture and processes them accordingly," said Christophe Delahousse, Senior Vice President of the Headend and Transmissions business units within Grass Valley. "This allows broadcasters to cost-effectively re-purpose 'large screen' content for smaller displays associated with mobile and other handheld devices, further enhancing the user's experience with the mobile content. Once receiver chips hit the market, we expect WGBH to be successful in the mobile video space, as they have been in other areas of broadcasting; including HDTV."
Grass Valley is one of the few vendors to offer an end-to-end mobile DTV video solution. The WGBH order includes a new Thomson Adapt IV Exciter with mobility software, a NetProcessor 9030, a Jade electronic services guide (ESG) server, two new ViBE mobility encoders in a statistical multiplexing mode, two ViBE audio encoders, and an Amethyst smart switch for redundancy. Grass Valley engineers handled all equipment installation and commissioning.
WGBH is a longtime Grass Valley customer, and now operates several Grass Valley K2 media servers and other equipment. The station currently operates a two-tube Thomson DCX Paragon MSDC-IOT transmitter, which will now also include the new Adapt IV exciter that has been retrofitted for simultaneous ATSC terrestrial and mobile video operation. WGBH's sister station WGBX operates a Thomson DCX Millennium single tube transmitter to broadcast its on-air signal.
Thomson ATSC Mobile DTV Terrestrial Broadcast Technology from Grass Valley is backward compatible with legacy ATSC transmission systems, enabling stations to use their existing DTV channel and the mandated ATSC 8-VSB modulation scheme. The technology offers several significant technological advantages over other systems, including the use of M/H Block Coding to provide maximum capability for signal reception.
The basic equipment needed to begin broadcasting mobile video services via ATSC Mobile DTV includes program encoders, a multiplexer, an ESG guide server, and a compatible DTV transmission exciter. Each of these devices is now available in field-tested production models from Grass Valley.