BSKYB CHOOSES CRYSTAL VISION TANDEMS TO PRODUCE NEW INTERACTIVE PORTAL FOR 7.4 MILLION HOUSEHOLDS (February 2005)

British Sky Broadcasting (BSkyB) is using TANDEM’s advanced audio embedding and de-embedding capabilities to provide 16 different audio tracks for a new interactive portal. Crystal Vision was the only supplier with equipment that could fulfil BSkyB’s technical requirements yet still fit within a small allocated space. The order comprised more than 60 PCBs, which have been in use since the 18th November launch.

BSkyB produces Sky Digital, which with more than 17 million viewers is the most popular digital television platform in Britain. Sky Active, Sky Digital’s interactive services portal, is available without subscription in more then 7.4 million digital satellite households. BSkyB needed the Crystal Vision equipment to produce an exciting new magazine-style format to meet the needs of the viewers that use the interactive services, creating a 16-screen video mosaic to provide faster access to Sky Active’s different features. Viewers would then be able to highlight one of the images using the cursor buttons on their remote control, which would allow them to hear the associated audio feed.

The order came about when BSkyB contacted Crystal Vision’s customer support engineer for advice on what sort of system could satisfy the broadcaster’s needs. A block diagram was produced showing equipment that could do exactly what was needed. This was followed by Philip Scofield, Crystal Vision’s Managing Director, attending a planning meeting at the BSkyB offices. Rob Hanstock, Project Manager at BSkyB said “Crystal Vision’s help in designing the system was invaluable.”

TANDEM is used for both immediate playout and recording onto a server, both of which need the audio to be arranged in completely different ways. The single video feed for the mosaic menu page contains the 16 pictures and also all 16 audio channels. The viewers’ set-top box will select one of 16 audio channels, depending on which of the mosaic pictures has been highlighted. BSkyB uses two versions of TANDEM for the immediate playout. First of all TANDEM-110 is used to de-embed the audio from the 16 video feeds. The audio is then transferred to TANDEM-200 which re-embeds the audio into the SDI output of the mosaic generator in the correct order for the MPEG encoders. There are 12 TANDEM-200s used for audio shuffling (four each for main, backup and test) which take the single SDI with 16 audios and generate four SDI streams, each with four audio channels. These then feed four MPEG encoders, since each encoder can only handle a maximum of four audio streams. TANDEM-200 is ideal for this task because it can handle two groups of audio, meaning it will take half as many boards to do the job compared to other manufacturers, saving money and space.

The feeds also need to be fed to an Omneon server in case backup playout is required at a later date and for this the TANDEM-200 shuffles the audio so that the 16 feeds are rearranged into eight mock stereo pairs – the left and right are actually unrelated mono feeds as arranging the audio like this saves valuable disk space. When the stored feeds are required for playout TANDEM-200 is used to convert the embedded audio back into the format required by the MPEG encoders. TANDEM-200 is ideal for this part of the application because it has advanced audio routing capabilities with the ability to split stereo pairs.

The equipment, which includes 47 TANDEM-200s and 16 TANDEM-110s, is located at BSkyB’s Osterley site in West London. The cards are housed in six Crystal Vision Indigo 2 2U frames with passive front panels, using just 12U of rack space, and are being controlled from the board edge after initial setup using Statesman, Crystal Vision’s PC Control software.

TANDEM is a family of dual analogue and digital embedder/de-embedders. TANDEM-110 is an entry level dual embedder/de-embedder with audio processing, and TANDEM-200 is an embedder/de-embedder with almost all of TANDEM-110’s features and advanced audio routing functionality. Control of TANDEM is flexible with board edge, frame active front panel, use of GPIs or Statesman PC Control software all being options.

In 1989 Sky Television was launched in the UK, with a four channel network Direct-to-Home service via the Astra satellite. British Satellite Broadcasting was launched in 1990, and its subsequent merge with Sky Television saw the birth of British Sky Broadcasting. Sky Digital, which was launched in 1998, now offers almost 400 channels.

Based at Whittlesford near Cambridge in the UK, Crystal Vision provides digital keyers and a full range of digital and analogue interface equipment including converters, decoders, encoders, distribution amplifiers and audio embedders to the professional broadcasting industry worldwide.