How Does That Yellow Line Get On TV During Football Games?

I though that was a first down?

Even the most diehard sports fans do not realize the amount of people it takes to broadcast a sports game. On even the smallest shows, there are camera men in the stadium, audio technicians, tape machine/EVS operators for replays, video technicians, producers, directors, a technical director, an 18-wheeler filled with millions of dollars of equipment…and this just covers the bare minimum to put a game on the air. Something that goes above and beyond a normal show is the “yellow line” you see on TV.

In the TV production business, it is called the “1^st and 10” line. ESPN, Fox, CBS, and NBC outsource the duties of putting the line on TV to a company called Sportsvision. While it may seem like a simple task to paint a yellow line across the field, it is actually very complicated.

At a minimum it takes a technician, a grip, and a huge computer. The computer is actually shipped to the TV trucks at each stadium or arena in no less than a 4 ft orange cube. There is also an attachment for each of the primary game cameras. The attachment connects below the camera and above the pan head of the tripod. The attachment is a little larger than an XBOX 360. You may or may not have noticed that the yellow line only appears on certain angles. The cameras that sport the attachment are large cameras, or “hard cameras”. Handheld cameras on the field do not utilize the Sportvision technology. (Next time you are watching football, see if you notice the absence of the line from on the field shots.)

Once the camera mount is attached, the Sportvision tech in the truck has to digitally map the field on his computer using input from each of the camera’s used. Infarct, every yard line has to be mapped. The mapping involves putting a digital overlay over the broadcast signal of the field. However, this is not an exact since. Football fields are not flat and the cameras are constantly moving and changing perspective. Therefore, the line is never 100% accurate. Hence in the picture above, the line is off by more than a yard.

It is actually pretty rare to see the line on the TV during a chain measurement. Usually the technical director will take the 1st and 10 line off the air when the chains come out for a measurement. This is similar to boxing or UFC fights when the clock is taken off the TV with about 5 seconds left. Both these instances occur for the same reason, they are not exact. The clock shown on TV during boxing matches is not linked to the official timer that the bellman uses. Therefore, to prevent the clock from showing :01 or :02 when the bell rings, the clock is taken off the air.

Exactness is just one of the problems that the Sportvision operator deals with. The line is keyed to pick up the green field. I am sure you have seen when the line starts to have issues (you may notice it digitizes) when players in green uniforms cross the line. Other issues occur when the line needs to be superimposed against a white 5 yard line that runs across the field or if the field is muddy or snowy. During the game, a Sportvision operator must adjustments by adding colors to the palettes to account for changing field conditions.

Finally, if you have ever called one of your buddies at a game while you were at home watching on TV, you may notice that events are taking place in your ear peace before you see them on TV. While some delay should be expected since the TV signal is beamed to space and then to your local provider who broadcasts it through cable lines or to your home dish, the Sportvision computer actually has to delay the video process before it can be beamed to space. The Sportvision computer superimposed the line 60 times per a second on the game feed. However, it takes a few seconds to sync up the line with the program feed, hence the extra delay.

While this may seem overwhelming, keep in mind that this is just one small aspect of the huge production operation that is putting a sports game on the air. I hope to explain more of the nuances of TV broadcasting in the near future as well as explore legal problems. Please subscribe to the RSS feed.