Striving for Quality: Sky adopt HDCAM SR

Sky has enjoyed a reputation in the world of HD broadcasting as something of a trailblazer. The first broadcasting platform to launch a full-blown HD channel service, BSkyB continues to drive the HD market in the UK by offering more channels and commissioning more HD productions than all the terrestrial UK broadcasters combined.

Not surprisingly then, Sky’s unofficial decision to adopt Sony’s high quality HD format HDCAM SR as standard has been interpreted as significant.

The advantage of HDCAM SR as a shooting and mastering format is that it is the least compressed 1920 x 1080 HD format, capable of 4:2:2 and 4:4:4 recording. BSkyB chief engineer Chris Johns declares: “The HDCAM SR format is a key part of Sky’s aim to deliver the ultimate customer experience. It is essential in ensuring delivered content is of the highest quality.”

Sky now insists that all commissioned content and delivered programs are supplied on SR tape. “It’s essential in sports programming because it has 12 audio tracks allowing the processing and archiving of effects and mixed audio on both stereo and Dolby mixes, giving the flexibility that modern broadcasters require,” says Johns.

On Sight chief engineer Richard Mills is also a big fan of HDCAM SR’s 12 audio track capability. “The reality in today’s world of increasingly high quality HD production is that HDCAM SR masters simply have more value in the international programme market,” says Mills.

“Nowadays you might need a Dolby 5.1 surround mix and separate M&E and narrative tracks and ordinary stereo which can all fit on HDCAM SR. They wouldn’t fit on an 8 track system unless you had Dolby encoding which some broadcasters don’t accept.”

“In the past this has been handled with a separate digital audio multitrack DA88 or DA98, but this is just another level of complexity – another thing to go wrong in the transmission chain,” says Mills. “Having it all on one machine now is absolutely essential.”

One thing that has, up until now, been missing from the Sony HDCAM SR range was a VTR machine that could cope with the format at the highest level. Now Sony is adding to its line up with its new HDCAM SRW-5800 recorder, which will offer all the key benefits of the HDCAM SRW-5000 and 5500 range, plus the enhanced capability of recording at 1080/50P and 60P at the higher 880Mb/s data rate. With a pathway to input and output DPX files, it’s been designed with the film and DI market in mind.

On Sight’s Richard Mills says it’s a big step forward. “It’s been the missing weapon in the armoury,” comments Mills, who has lost no time in ordering the Sony SRW-5800 to handle – amongst other things – an increasing demand for DPX file transfers from On Sight’s clients working with digital intermediates. “The option of recording at 880 Mbits per second has in the past only been possible on the SRW-1 field recorder which is married to either a Sony CineAlta F23 type camera or the ArriD20.

In fact, according to Mills, the absence of a studio VTR has held back the amount of shooting that people have done at 880Mbits. The release of the Sony SRW-5800 means that could be about to change.

Another benefit of the VTR’s ability to record at higher data rates is that it gives the option of adding effects at higher frame rates. For example, On Sight played back elements for the title sequence of BBC1’s Robin Hood recorded by producer Tiger Aspect at 1080/50p - at 25p to produce half speed arrow effects. “It’s been used for quite a few shoots like that to give half speed motion at full 1080 resolution,” says Mills.

There is a trade off however, warns Sky’s Chris Johns. In delivering a higher quality VTR at a price point close to that of HDCAM, the SRW-5800 has sacrificed some of the high end edit functions such as pitch correction, audio cross fades and pre read editing, as well as the ability to record in ordinary HDCAM.

Overall, Johns insists it has the potential to become the new high end workhorse in the broadcast industry. “It offers high end studio record and playback in 1080i or 1080p at either 4:2:2 or 4:4:4 and provides ingest functionality by either dual link or file transfer to non linear edit systems, servers or transmission systems at speeds up to twice real time. Importantly, it comes at a price that will give it potential to be the preferred media solution for broadcasters and post houses as high definition continues to make its impact in the marketplace.”

For international clients in the USA or Japan demanding masters at 59.94 from an HDCAM SR master shot in Europe at 25p or 50i, On Sight partners the HDCAM SR format with Alchemist Ph.C - HD, capable of a fully frame interpolated motion compensated conversion. “It inserts entirely new frames without artifacts,” insists Mills. “Alchemist HD provides the perfect partner to HDCAM SR because conversions are seamless, maintaining the quality of the mastering format.”

Main image from BBC © 2008. Text reproduced with permission from On Sight © 2008.

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