As the market begins testing the integration of digital products, lessons are learned in what features are most valuable to broadcasters. An interesting case of compatibility arose in choosing a digital format for the cbc.

Pat Whittingham, executive vp of Sony of Canada, says cbc’s choice to convert news and sports production equipment to Sony’s sx format has international significance: ‘cbc will be the largest order for news conversion to sx yet.’

The sx conversion will affect the entire digital production path at the cbc and begins the introduction of MPEG-2 compression at the production level.

Conversion to sx will bring cbc network operations into the digital age in a cost-effective way. These departments had been delaying equipment upgrades for years waiting for a format standard to emerge.

sx is the recent sister of the higher quality Digital Betacam, both providing 4:2:2 digital component capability. ‘sx employs roughly a 10:1 video compression to Digital Betacam’s 2:1,’ Whittingham says. ‘This reflects the efficiency of MPEG-2 compression.’

sx is referred to as a ‘middle format.’ Digital Betacam is best used in higher-end production. Non-sport and non-news programming require much more in the way of transfers in post and in creating special effects. Digital Betacam’s high resolution and discrete color content is retained longer than with sx, so there is less generational loss – but the cost is higher.

There is also a new line of MPEG-50 vtrs being used by cbs and Italian network rai that work well in conjunction with the higher resolution Digital Betacam.

dvcpro, Panasonic’s competitive digital format, is used in cbc’s Windsor and Moncton offices on a daily basis and at major sporting events – the Commonwealth Games in Kuala Lumpur and by the host broadcaster at the Pan Am Games ’99 in Winnipeg, where dvcpro was the official format for host.

cbc also used sx at the Pan Am Games for domestic coverage and at the Winter Olympics in Nagano, and sx is used extensively in cbc’s foreign bureaus. sx was first used by the cbc for North American broadcast at the ’96 Summer Olympics in Atlanta.

Panasonic had an early lead in the selection process, as the cbc’s French network chose Panasonic for some of the regional bureaus. sx was originally designed for high-speed transfer to servers, but as sx became more prominent in news production, insert editing was required.

Because MPEG-2 is an elaborate compression scheme, it took a lot of rethinking of design issues to make those structural changes.

With the development of frame-accurate, insert-editing in sx format, Sony and Panasonic gear was at the same stage of functionality and it was time to test the wares. Two test sites were set up for six months to investigate the suitability of the new digital formats.

Sony’s sx was tested in Winnipeg and Panasonic’s dvcpro and DVCPRO50 was tested in Moncton. There was a steering committee with French and English department heads and senior editors, camera operators and engineers testing the competing technologies, making assessment notes and keeping in close contact with both manufacturers.

Jim Rogers, director of cbc’s Toronto television production centre, says ‘both are good products, either format would have worked.’ Both are affordable digital formats, both offer savings in equipment weight, both are working with other manufacturers to ensure compatibility.

But the cost of implementing sx was reduced by its compatibility with Beta sp. ‘One of the greatest factors is backward compatibility,’ Rogers says. ‘We have a library of a half million tapes. The cost of introducing an incompatible format would have significantly increased our operating cost and space considerations. We would accumulate many more tapes in making dubs and our machine count would almost double.’

Compatibility with the cbc’s huge sp archive was most important to the news operations team. Says Bob Conroy, director of production for Newsworld and news current affairs: ‘At the network level, analytical editorial content is important and we need to use our archives. Sharing resources with foreign offices using sx is also easier.’

sx tape width allows backward compatibility. sx and sp are both a half-inch wide, so old and new tape stock will fit into the same machines. With any other sized format they would need to have two machines at every workstation and there would be a generational loss in conforming the formats.

Rogers says another major factor was the lower cost per minute of sx tapes. With tape stock recording twice as long as sp, camera operators can shoot more and still have less tape to carry in the field and less weight in airport baggage. Less tape also means editors need less storage space and can archive more material.

Editing equipment was another factor. Conroy says transfer speeds and editing features made sx the best candidate. ‘With sx we get four times the transfer speed of sp when digitizing. There is also a shot marker that will transfer only the good shots. That cuts down the waiting time and increases the editing time. It also minimizes wear and tear on the equipment.’

Conroy was also pleased with Sony’s reaction to cbc’s comments on working with Avid. Sony and Avid announced a working alliance which, amongst a number of initiatives, provides for native mpeg-based editing in their news cutter nonlinear editor. ‘This type of cooperation helps broadcasters control the costs of conversion and it is an important consideration,’ he says.

‘Panasonic was ahead of the game in some respects,’ says Conroy. ‘Sony traditionally uses proprietary software but knew that if they were going to deal in the marketplace, they needed to make their chipsets available to other suppliers like Grass Valley and Avid or they would end up on their own little island.’

Up-conversion is another consideration. ‘On mpeg 4:2:2 Profile, a digital component signal has sufficient chroma [i.e. color] performance for a reasonable up-conversion to dtv/hdtv,’ says Sony’s Whittingham. ‘cbc’s decision to purchase 16×9-4×3 switchable cameras positions the corporation well for converting their news and sports to a wide-screen format and up-conversion to hdtv.’

The equipment to be upgraded to sx will be eng cameras, camcorders and editing equipment, both linear and nonlinear. Although the engineering department does not have too much involvement in the news and sports production conversion stage of replacing cameras and editing systems, it is involved in the decision-making process to make sure the conversion path leads to future options.

Rudi Lingohr, director of engineering for broadcast services at English cbc, says, ‘The sx conversion forms the basis for migration to MPEG-2-based systems at all levels in the broadcast chain, from acquisition to transmission. mpeg compression is rapidly becoming the industry choice for digital distribution.’

‘With MPEG-2 in production,’ Lingohr says, ‘transcoding for mpeg distribution is less detrimental to the signal than having to transcode from another compression scheme, because it stays within the mpeg family.’

Similarly, dvcpro operates on a distinct dvcpro compression scheme that is compatible with dvcpro recording, field acquisition, post, nonlinear editing, video servers and archival storage equipment. All broadcast products in the dvcpro chain stay within the dvcpro compression scheme, as all Sony products stay within the mpeg compression scheme.

atsc-standar digital transmission to the home is also on the horizon.

‘The sx news/sports conversion is the first step toward digital conversion,’ says Lingohr. ‘When the crtc decision is made for atsc digital transmission to the home, part of the infrastructure will be in place.’

When the crtc sets the timetable, the cbc engineering team will begin installing atsc-compliant transmitters capable of delivering MPEG-2 signals to Canadian homes.

Despite the operating savings, the sx conversion is a major economic undertaking in a national organization. ‘It is a long process fleshing out current inventory and deciding which programming area should go first, whether it be national network sports or regional news departments,’ Conroy says.

The process of converting all cbc equipment to sx will take about two to three years, beginning with the Western production centres. The Windsor and Moncton offices will continue using dvcpro after having made the transition already and will be the last to convert to sx.

‘Capital budgets are a real limitation,’ Rogers says, ‘even though virtually all of our existing Beta sp equipment is ready for replacement right now there is only so much that can be done in any one fiscal year.’

Discussions about other progressive steps at the cbc such as developing a central news server for online editing to program broadcast may not begin until next year or the year after. But sx again will be of benefit because the format requires less bandwidth and less hard-drive space than Digital Betacam or dvcpro.