Superimposing things on live TV?

VaSteve · 06-22-2008, 06:25 PM

I watched the NASCAR race at Infinion this afternoon. They had super imposed these signs that said "turn 2" "turn 3" etc. How is that done one live TV? The way they were panning around, I don't understand how that could stay within the frame and not move like all the images for Bill Engvall's show.

Same deal with football... the line of scrimmage stays when the camera moves. How's it work? (Don't say "computers"

).

stomachmonkey · 06-22-2008, 06:27 PM

Alpha Channel

VaSteve · 06-22-2008, 06:31 PM

Quote:

Originally Posted by stomachmonkey

Alpha Channel

No, it was on TNT this week.

stomachmonkey · 06-22-2008, 06:40 PM

Sorry.

An Alpha Channel is a mask.

It's just an additional video track, image can be static, with transparent areas.

Think of a bug splattering on your windshield. The windshield with the bug is the second video layer.

If you imagine the windshield does not move but the scenery pans.

Stanley · 06-22-2008, 06:45 PM

Interesting... Looks like one company is cashing on this technology http://www.sportvision.com/

varmint · 06-22-2008, 06:46 PM

alpha channel is part of it. they use motion tracking in after effects. pick out a couple markers in the real world. the computer identifies them, and lays an image down relative to their position. it even adjusts for perspective.

at least i think that's what you're talking about.

VaSteve · 06-22-2008, 06:58 PM

Quote:

Originally Posted by stomachmonkey

Sorry.

An Alpha Channel is a mask.

lolz. I googled it after you posted. I couldn't resist the opening to have some fun.

Quote:

Originally Posted by varmint

alpha channel is part of it. they use motion tracking in after effects. pick out a couple markers in the real world. the computer identifies them, and lays an image down relative to their position. it even adjusts for perspective.

at least i think that's what you're talking about.

Yes, must be. I forgot about those "trackers" for the cars. That stuff is top notch and well used.

thanks guys

trekkor · 06-22-2008, 07:02 PM

First off, the race was garbage. Full course yellow flags were flying for no reason.

Haven't these guys heard of a local yellow???

It was fun seeing the fake 'Jumbotron' mounted to the top of the luxury suites.

KT

VaSteve · 06-22-2008, 07:06 PM

Quote:

Originally Posted by trekkor

First off, the race was garbage. Full course yellow flags were flying for no reason.

Haven't these guys heard of a local yellow???

No kidding, it's a huge track. A little spin that the guys gets out of and they toss a f/c yellow. Nonsense.

Porsche-O-Phile · Porsche-O-Phile's Garage

I've noticed this as a trend in racing in general and think it has less to do with legitimate concern for safety and more to do with making the races interesting. For example, how often did we used to see safety cars in F1? Hardly ever. Now it's virtually every race, making the competition far more interesting since you're going to get the obligatory "bunch up" behind the SC and the restart. Kind of like two (or three, or four) mini-races in one. Is this done deliberately? Yep. I'd bet it is.

But nobody dares call the officials out on it since they'd just respond by saying "you mean you're not concerned about SAFETY!?!?" (oh the horror!)

The reality is that racing can be done safely without a lot of the gimmicky SCs and restarts that are done these days. . .

VaSteve · 06-22-2008, 07:24 PM

If you watched the race, the announcers were very explicit that this was entertainment. They said something to the effect of "to us, this is a sport, but to all the fans, it's entertainment." At least they were honest. It's hard explaining motorsports to someone that's never turned a wheel except during their commute. They think the car does all the work.

ckissick · 06-22-2008, 09:02 PM

As for football games, they first accurately survey the locations of the cameras in relation to the field. Once the precise locations of the cameras and the field are known, a computer simply overlays digital yard markers onto the field.

It only puts the image onto a green background so the lines don't go through jerseys and the ball. It has to be a specific shade of green so the lines don't go through the jerseys of the Eagles. I've noticed the line on jerseys where there is a good grass stain.

Pazuzu · 06-22-2008, 09:14 PM

Y'all are forgetting the primary question...

You are not watching live TV anymore. Everything is fed through satellites and computers, and there is a "massive" delay (read, several seconds).

You can even see the delay from digital if you watch a TV receiving analog over-the-air next to a TV receiving digital OTA...the digital TV is lagging by about 6 seconds.

Cable and Dish? I don't even want to think about how much delay they have these days...