Film-Tech Forum ARCHIVE: Overlays on TV sports events -- How?

This is topic Overlays on TV sports events -- How? in forum Film-Yak at Film-Tech Forum ARCHIVE.

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Posted by Frank Angel (Member # 248) on 10-09-2008, 04:14 PM:

Anyone know just how they superimpose graphic on top of, or better still underneath the image in sports broadcasts -- like the down line on the football field. It moves with the shot and objects can cover it (players cross it and it their image blocks it); it really looks like it is on the field.

They used it in the Olympics and I've seen it in other such events like bike racing where they have actually company logos looking like they are painted on the road....until they fade out and are replaced by another one. Great effects, but HOW?

Posted by David Stambaugh (Member # 1102) on 10-09-2008, 04:21 PM:

Apparently it takes 8 computers and a lot of 3D modeling etc. to superimpose the first-down line in a televised football game.

Posted by Joe Redifer (Member # 3) on 10-09-2008, 04:48 PM:

That site said:

quote:
Given that the camera can pan while viewing the field, the system has to be able to recalculate the perspective at a rate of 30 frames per second as the camera moves.

Wrong. It's 60fps.

Also, the video is buffered a second or two so it doesn't have to do it in real time.

Posted by Robert Minichino (Member # 3495) on 10-09-2008, 05:20 PM:

Yes, 60 frames or fields, either way. But even if the video is buffered it still has to do it in real-time or it would have to start dropping frames as it backed up.

Posted by Joe Redifer (Member # 3) on 10-09-2008, 05:50 PM:

I should have said it doesn't need to do it "live". In fact that would be impossible. It has to take the frame from the camera and then determine WTF is going on and then it has to paint the useless line over it which nobody cares about and then it has to send it out. It increases lag. So when you're gasping your chest on that heartwrenching play, the people at the stadium already know how it ended.

Posted by Mark Ogden (Member # 43) on 10-09-2008, 06:25 PM:

The CBS Sports package is supplied by Princeton Video, who first developed the technology. Here's a quick explanation.

Posted by Bruce Hansen (Member # 281) on 10-09-2008, 08:42 PM:

Yes, it is real time. These things are used LIVE on the air, and intercut with cameras that do not have the supered line. There is a unit that attaches to the camera and the tripod. It measures the movement of the camera. It also hooks into the lens controls so that it knows where the zoom and focus are. Before the game the camera is pointed to certain points on the field, and the "line" opperator inputs those points into the computer. The system then can super a graph of the yard lines, and the opperator can tweek anything that is off. A sort of croma key (or matt) is used to have the line show up on the GREEN grass, but not on the players. Want to see the keying system have a hard time? Watch when the sun is setting, and there are shadows on the field. Not only is there a difference in the amount of light, and therefore a difference in the intensity of the colors, but the shadows are more blue, then the area in the sun.

Depending on the importance of the game (more viewers = more money from commercials) there can be between 0 and 4 cameras equipped with these things.

Last week I worked on the East Lake golf tournament for NBC (and the Golf Channel), and there is now a version of this "line" system for golf.

Any graphics, such as the score are keyed over the image in the production switcher, and have nothing to do with the "line" system. These come from a character generator. This unit outputs the graphics video, it also outputs a "hole cut" signal, to tell the switcher where the graphics are, so that they can be keyed into the selected video.

Posted by Mike Blakesley (Member # 26) on 10-10-2008, 01:10 AM:

quote: Bruce Hansen
there is now a version of this "line" system for golf.

What the hell for?

Posted by Joe Redifer (Member # 3) on 10-10-2008, 01:25 AM:

People who do broadcast sports figure that people actually want shit superimposed all over the place. But for golf it is probably yard markers since just telling the audience how far the ball traveled is simply not good enough.

Ever notice that the announcers always ignore the line? You will see a dude with a football cross a line and get tackled just on the other side. It clearly looks like a first down if the line were accurate. The announcers say stuff like "that may be a first down" and then they actually measure even though you can clearly see the ball on the other side of the line. hen they rule that it was NOT a first down.

Line=fail.

Posted by Tyler Potts (Member # 4952) on 10-10-2008, 01:59 AM:

I'm just glad I don't see that freakin' glowing puck the NHL tried to do in the early '90s. It was constantly a foot behind the puck, and for someone who grew up in Buffalo, I know how to follow hockey.

Posted by Frank Angel (Member # 248) on 10-10-2008, 02:47 AM:

Seems like an AWFUL lot of technology and $$$ just to put something in the picture that no one give a hoot about. Ads, as obnoxious as they are, at least you can understand that they make money; the line makes nothing.

Just like the color announcer. Years ago they did an experiment -- I think it was on Fox -- just using the field announcer as the play-by-play (sparse that it is) on the broadcast audio -- no color, no other play-by-play -- same thing the stadium audience hears. If it's good enough for them, it should be good enough for the TV audience. Hell, the tv audience can see much more that the stadium audience -- why do they need enhanced play-by-play, plus the incessant, usually innane yammering of the color guy. I LOVED it, but it was very short lived -- only two games. Then it was back to business as usual....a barrage of 90% useless, ego maniacal, look-world-I-can-talk-without-stopping-for-two-hours bullsheet.

Yah, the line is very interesting in its execution and no doubt clever, but bottom line....it's useless. All costly glitz and no substance.

Posted by Joe Redifer (Member # 3) on 10-10-2008, 04:07 AM:

What's nice about many sports games broadcast in Dolby Digital™ 5.1 audio is that you can unplug the terminals for the center speaker and it is almost like being at the stadium. You don't hear any announcers, just crowd cheers and whatnot. Since it is discrete, there's no crosstalk like there would be if you tried this with a Pro-Logic signal.

Posted by Scott Norwood (Member # 30) on 10-10-2008, 08:14 AM:

With ATSC, it should be possible to broadcast the game without the "additional material" (lines, etc.) on a subchannel. If there is an ATSC equivalent to the SAP channel, they could even have a non-announced version of the game. Is anyone doing this? Probably not.

Personally, I object to the fake stadium ads that often show up in televised baseball games (and maybe other sports, too). These are meant to look like billboards at the ballpark, but are actually inserted into the broadcast picture even though they don't exist in real life (and don't show up at all in instant replays). At least with football, the yellow line (which I don't really like either) looks fake and is obviously not on the field. It seems to be boarderline deceptive to add in fake advertisements that are intended to look real. Why not just sell advertising space on the players' uniforms and be done with it? Also, the shots with the fake ads seem to be delayed by a frame or two, as there is usually a noticeable gap when cuts are made to and from those shots.

The technology is clever and interesting, but I don't see how any of this would increase viewership. I watch very little television, but would watch more if the networks would get rid of on-screen logos and fix the incessant lip-sync issues that every station seems to have to some extent. Bad sound sync would not have been acceptable in 1960, so I see no reason why it should be acceptable now.

Complaints aside, current HD sports broadcasts look amazing (usually). It's amazing how much picture quality has improved in the last decade. Too bad almost everything else about television is worse than it was in the 1990s.

Posted by Lyle Romer (Member # 1266) on 10-10-2008, 08:33 AM:

quote: Joe Redifer
So when you're gasping your chest on that heartwrenching play, the people at the stadium already know how it ended.

This is why I like going to sporting events. When I watch on TV I know in the back of my brain that what I'm watching happened several seconds ago. You've got processing delay in the truck, delay from truck to satellite, satellite to network control, network control back to satellite, satellite to distributor, distributor repackaging of data, distributor to satellite or cable system and then satellite or cable system to your house.

Plus, if they are still using it there is the Janet Jackson live delay.

In some cases, the delay can be 10 seconds or more for a "Live" event.

Posted by Joe Redifer (Member # 3) on 10-10-2008, 10:47 AM:

quote: Scott Norwood
Also, the shots with the fake ads seem to be delayed by a frame or two

Yes, they "wobble" or float when the camera is not perfectly still. It probably wouldn't work at all if Paul Greengrass was holding the camera. Realtime, my ass!