Sports have been a major influence on the development of broadcast technology over the past 15 years. Satellite and cable broadcasters have used sporting events, particularly football and high-profile one-off tournaments, to attract viewers to their channels. To do that, they have paid sometimes inordinate amounts of money to secure the rights to games and seasons, while using the latest equipment and technological advances to create coverage that is different and more innovative than what is offered by rivals.
HD use
In Europe, several broadcasters have already begun either HD sports transmissions or are capturing events in the format, building up a library of material to provide continuity for when full services begin.
The Euro 2004 football tournament, staged in Portugal, was originated in HD, with coverage coordinated by host broadcaster Euro Broadcast Services (EBS). This was a joint venture formed by Portuguese public broadcasters Radiotelevisao Portuguesa (RTP) and Radiodigusao Portuguesa (RDP), and facilities were provided primarily by Belgian OB company Alfacam, as well as British hire and systems operation Gearhouse Broadcast. HD pictures were made available to Japanese and American networks, as well as to Alfacam's associated HD channel, Euro 1080, but the majority of transmissions was of SD pictures downconverted from the main HD signal.
German broadcaster Pro Sieben has been at the forefront of preparations for European HD, beginning HD tests during the autumn of 2004. The culmination of the project was the coverage of the Champions League Final between AC Milan and Liverpool in May 2005. This was transmitted in HD on ProSiebenSat.1, a first for a major sports event on the channel.
The next link in the chain was the Confederations Cup in Germany last June. It originated in HD, although it was estimated that only two percent of viewers watched in the format. Broadcast coverage was overseen by Host Broadcast Services (HBS), which covered the 2002 World Cup in Korea and Japan and will broadcast the upcoming World Cup tournament in Germany.
HBS announced in December 2003 that it intended to become “all HD” in 2006, and so its main equipment supplier, Grass Valley, pledged that it would have all the necessary HD equipment built and tested by the time of the Confederations Cup. Cameras are the most obvious aspect of HD production, being the acquisition front end. Although several manufacturers produce HD systems cameras, at present Grass Valley and Sony have more or less split the sports market between them.
The Grass Valley LDK6000 is a familiar sight around sports stadiums and is arguably a more common choice than the Sony HDC-950 HD camera. The former is used by BSkyB for its coverage of Premier League football in England. It also was featured at the Confederations Cup and will be used by HBS for the World Cup.
The interlaced (i) method of coding HD pictures is preferred by broadcasters for live events and for sports in particular because it gives the look of a traditional video shoot. This is because the means of scanning a picture is similar to traditional analog coding systems such as PAL in that the picture is created from the odd and even numbered lines of the picture transmitted consecutively as two separate fields. The odd horizontal lines are sent first, followed by the even. Each pass takes one fiftieth of a second, and the two fields are then interlaced as one picture.
The favored HD format for sport is 1080/50i. All 64 matches of this year's World Cup will be originated in HD 16:9, to the HD-SDI 1080i/50 standard to achieve worldwide compatibility. A lens that is popular among sports broadcasters, including BSkyB for its Premier League coverage, is the Fujinon 86-1 model. All cameras at the World Cup, including Super Live Slow Motions (SLSM), will be HD. Each HBS OB truck will produce two outputs: HD-SDI 1080i/50 transmitted at 1485Mb/s and SD-SDI 625i/50, running at 270Mb/s. Depending on the operational model chosen during the tournament, the OB van will produce a single HD output that is down-rezzed to SD at source.
HD specialist cameras
Manufacturers acknowledge that the core HD equipment is now in place in the form of standard cameras and video recorder decks, so the demand now is for gear that adds extra detail and can be used to create individualistic coverage. Specialist cameras are vital in broadcast sports coverage because they allow either greater analysis of the action, particularly through the use of slow motion, or alternate angles to the main shots. For the World Cup, HBS will use Grass Valley LDK 6200 super slow-motion cameras.
Slow-motion is now possible for HD, both on cameras and through disk recording systems. Claiming that it has been able to cope with HD since the early 1990s, EVS is used widely for a variety of sports. There is still some work to be done in this area, at least as far as cameras are concerned; three times slow-motion is only now becoming feasible for the new resolution format and will be generally available soon but not in time for the World Cup.
Wireless cameras are another area in which HD has lagged behind SD technology. Small specialist manufacturers such as Link Research have led the way, with the big combines choosing to establish standard cameras before moving onto radio-based systems. During IBC2005, Link introduced LinkHD, a low-delay wireless camera system that operates on all HDTV formats. British rental company Presteigne Broadcast Hire became the first European equipment supplier to buy the new system, making it part of the HD flyaway packages used at the 2006 Winter Olympics in Torino.
TV sports coverage has been revolutionized in the past 15 years by the use of miniaturized cameras, which reach areas that operators with standard units can't. The Stumpcam in cricket, the Halibutcam for swimming, car- and jockey-mounted cameras in motor and horse racing respectively, and rugby's Post Cam have put home viewers in a better position than spectators at the venue as they are able to experience the event from the perspective of a participant and from several different angles.
Special cameras are generally adapted from commercial devices, often those designed originally for surveillance work, as these offer the small headend blocks that enable the camera to be placed in otherwise inaccessible places. Adapting these for SD operation is difficult enough, and now organizations such as the BBC Special Cameras Department are turning attention to HD. Cameras such as the Sony Z1 can provide the basis for new models, and there is work being done to ensure that the optics are better for HD special devices. Meanwhile, the radio links used to connect the camera to the OB truck are being upgraded for the higher resolution pictures.
HD graphics
Most viewers will have noticed a change in graphics for TV sports over recent years, with match scores now permanently on-screen and other, more occasional information often superimposed on the action or field of play, usually using perspective technology to give a 3-D effect. It is no surprise that HD graphics are difficult to achieve, at least in these relatively early days of the technology. Much of the graphics being seen on HD services in the United States are upconverted SD files, and there is concern that as with general titles, information can break up when either up- or down-rezzed, appear jerky if it is animated or be out of position in the picture.
When working with a converted HD stream, many engineers are now inserting graphics and text information after the conversion process, but the first generation of HD graphics engines is now beginning to appear. Pixel Power, for instance, introduced its Clarity 5000 system at IBC2005, and shipments have now begun. The challenge for graphics systems designers has been integrating the 5X increase in data compared to SD. There is more flexibility; however, a score graphic at 40 lines high for SD will still be readable in HD at 30 lines high, thereby giving more picture space to the action.
Graphics for the 2006 World Cup are being produced by HBS in cooperation with football governing body FIFA and HBS' on-screen graphics partner, Delta Tre. These will be in both HD and SD and will be consistent with the opening animations. The multilateral on-screen graphics present relevant statistical information about the teams, match and players. Other multilateral feeds are clean of graphics to make editing easier. The graphics will appear at the bottom of the frame, except in the case of long lists, pre- and post-match periods, and at half-time; this leaves the upper part available for appropriate unilateral usage.
HD surround sound
What is seen on-screen contains the most obvious benefits and challenges associated with HD sports production but there are other elements that must be considered. One is audio and since the early days of the HD systems that are being instigated now, the natural accompaniment has been 5.1 surround sound. Broadcasters across Europe have been experimenting with 5.1 for some time, but BSkyB's approach has attracted particular attention.
Sky has long been a proponent of surround sound, not only for its movie services but also for sport. In 1994, the broadcaster introduced analog, matrixed Dolby Pro Logic (DPL) surround sound on Premier League coverage, putting home fans in the middle of the crowd and the action. Dolby Digital 5.1, the multichannel system preferred by Sky, gives five discrete channels plus a low-frequency channel, although that is predominantly a film tool. To maintain compatibility with DPL, stereo and mono and to obviate the need for additional mixes, Sky has specified the Dolby DP563 encoder for the OB trucks. The unit has six digital input channels and allows a stereo/DPL compatible mix to be produced without the need for a separate balance.
To capture the crowd atmosphere, the Soundfield SPS422 surround sound microphone system is used, with additional Sennheiser mics around the pitch for ball kicks and incidental banter. These effects are mixed front left and right and into the rear channels. The commentary is kept firmly in the center dialogue channel. The Dolby E carrier system carries the multichannel audio signal as a conventional two-channel stereo stream, which is embedded with the video signal.
HD switchers
Even more in the background is the switching process, but this is crucial for both distributing signals and integrating specialist cameras into the main program feed. Among the systems already on the market for this purpose is Grass Valley's Kayak HD switcher, which upconverts raw HD signals.
In keeping with the higher resolution, HD pictures are widescreen, but in sport, the 4:3 aspect ratio is still to be found. During the World Cup, the standard broadcast delivery will be 16:9 SD, but it has been accepted that some broadcasters may want to convert that signal to 4:3. Among the options offered are letterbox and center cut-out so that 16:9 pictures can be presented on 4:3 screens. This can be done easily using an aspect ratio converter. Broadcasts can be in either 16:9 or 4:3 or both using separate channels. This requirement is likely to become less necessary as more consumers buy flat or widescreen 16:9 HD-ready sets.
Conclusion
As HD is used more widely for sports, problems continue to be encountered, such as movements occasionally appearing blurred in broadcasts using the interlaced standard. This is attributed to the continuing European lack of decision over a uniform standard for HD. Regardless of that, however, sports are now at the forefront of the new age of high-resolution broadcasting.
Kevin Hilton writes about television post production and audio.
