What is progressive scan?

is senior writer Jonathan Strickland. Hey there, So we uh where we're going to talk about something that you might see and not understand, at least in my case, because you know, because you see it and you don't understand it exactly. This comes This comes to us courtesy of a little listener mail and here we go. Hi. My name is James. I love how stuff Works. I was reading an article on h d M I and kind of learned how progressive scan works. But better to hear

it from the experts. What can you tell me in podcast form? Well, James, um, first, as they have the whole experts. I know, maybe we're supposed to a forward this onto someone, but we'll we'll give it a shot. So progressive scan, we're talking about television's here, or monitors, computer monitors as well. Can I progressive scan most do. Um, and Uh, it's it's a technology specifically that deals with

how your television generates images. Now, your old analog TVs and the the big old bulky machines that we used to watch television on us to some of us still own analog TV. Yeah, a lot of our listeners have never watched television on one of those. Can you can you think? Can you wrap your head around that? Okay? So okay, the old people in the room, Uh, we used to and sometimes still do watch television on these old analog television sets. And these TV sets use a

technology called interlacing display images. So every single time you're looking at a television that's on and showing something like some sort of television program, Um, you're actually looking at thousands and thousands and thousands of tiny little dots of light that we call pixels all right now. And they come in rows, yes, rows, and columns in fact, uh, and so we we usually look at them. Uh. You can either look at them as horizontal rows or vertical columns.

The idea here is that the television sort of paints this picture with light, all right. The old analog TVs used an electron gun to paint these pictures and we'll probably talk more about the electron gun, how it did this, and kind of the evolution of TVs and another future podcast. Yeah, we've got a lot of requests for that, so that

that's in the that's in the works. We haven't we haven't tackled that one yet because it's a it's a little bit heavier of a topic than this, and any rate, it paints the pictures line by line, all right, and with the old interlacing technology, it wouldn't paint the entire picture, it would paint every other line, uh per per scan

if you want to call it that, all right. Basically the even lines and the odd lines, and it alternates between the two and each set displays for one of a second, So thirty times a second you get all the odd lines, and thirty times a second you get all the even lines, and they're they're alternating back and forth. That gives you your sixty hurts refresh rate. Okay, but you're only getting thirty per set of lines. So that's called interlacing. It interlaces the odd lines with the even lines.

Progressive scan is different, and progressive scan you get all the lines shown on each on each blasts. So instead of getting you know, half of them every thirty and the other half sorry, thirty every second for half a thirty every second for the other half, you get sixty of all of them per second with a sixty hurts refresh rate. Yes, because let's talk about sixty times per second. That's what the hurts means in this case. Um, So it's painting every line on the picture. Now, what does

this mean to you as a television viewer? Well, did you want to take a stab? Well, I was going to say that damage appears more stable, yes, and it doesn't display as many artifacts, which is a very important digital bits that don't seem to you know, Yeah, they

look really jagged, these little jagged exactly, there's these. If you've ever watched, um, say, a really good DVD on a on an old interlace television set, um, you might notice that there are these occasionally these little jagged uh images that show up as the as the show or the DVD plays. And it's once you notice them, it's hard not to notice them. From that point on, you start noticing them in everything, and um, it's very irritating. Progressive scan eliminates a lot of that because it does

smooth out the picture. So this is why when you were first looking at h D t vs back when they were first becoming popular. Uh, you know, you had a couple of different choices. There was the seven twenty and the ten eight, which that refers to how many lines of pixels you have? Right, yes, so for for top to bottom there are seven lines or right, so, and that that changes the resolutions the top to bottom, like I think it's left right that would make sense.

I'm sorry, because left right, if you have a ten a D line TV, that's the sixteen by nine resolution versus the three. Yeah, OK, so I apologize, that's all right. No, I get confused all the time about this guy's I mean I write about them all the time, and I still have to look it up because there's so many

numbers that are involved here. So, but seven twenty, if you you could get like a seven twenty television, that would mean that it was a progressive scan television that had the seven or twenty lines of resolution or ten eighty I resolution, which mean I had a thousand eighty lines of resolution and that was interlaced by the way, the seven ten eighty thing. That's not really how many lines of resolution you have? How many lines of pixels? But we're gonna stick with that just because that's the

what the industry standard is called. Yeah, um, so don't write in and tell me you know, actually it's not really one thousand eighty because I happen to know that. Um, but we're yeah, well, don't pause the podcast. People listen to it all the way through and then tell us how stupid we are. Um, actually we're great. So anyway, the you might think, all right, well, if this television has more lines of pixels, it must be better, be because more is better, right, well, not necessarily. Yes, you

might have more pixels per on your screen. You might, and which more means you're gonna have smaller pixels usually means you have a sharper image, right, a sharper picture. That's why the definition really is all about, not the sharper image. But you're smirking at me. So, so usually more pixels does mean better. But when it comes to interlace versus progressive then you have a different argument. You're saying, well, progressive scan gives you a smoother image, especially when stuff

is moving around. Um, and interlace can give you these artifacts so in that case, it might be better to get the seven twenty rather than the ten eight, especially if you're talking about smaller TVs, because these higher resolutions aren't really that noticeable on televisions that are around I don't know, thirty six inches or smaller. Three six inches is a big TV, and it really is kind of big.

But when you're starting it's only when you start getting up into the fifth and sixty inch televisions that you're really start to need to worry about a ten eight resolution. And if it were ten A d I with the interlace, it would not necessarily be a better experience than if you were to get the same size. And now eventually manufacturers started to come out with ten A DP models. So these are the progressive scan uh sets that have one thousand eighty lines of resolution, and uh, those are

really nice. They look really sharp. Um, again, unless you have an enormous television, it may not really make a huge difference how many lines of resolution are in there, but the the technology behind it matters a lot. Yes. Now, another thing to keep in mind is the refresh rate on your television. Now, this is this is different from whether it's progressive or interlaced. Your refresh rate is how many times your television is generating that image per second.

And as we mentioned before, we were we started off talking about sixty hurts, where it was either going to be thirty times per second per set of lines with interlaced order sixty times per second for the entire picture with progressive um. But you now can find televisions with much higher refresh rates. One hurts is pretty much common now And if you go into an electronics store, yes, so that means it's regenerating that image a hundred twenty times per second. Uh, you can even find higher as

refresh rates. Two hundred forty hurts is not unusual. In fact, someone in the office just recently purchased a two forty hurts television. Was not It was not I, and obviously wasn't me. Now it was someone else. I won't mention names because I didn't ask if I could, But someone else in the office for Christmas received a or went out and purchased actually a two hurts refresh rate television. Now that means that the image refreshes two hundred forty

times per a second. Now, refresh rate helps smooth out images that are in that are moving very quickly. Yes. When I say moving very quickly, I mean that objects on the screen appeared to be moving. I mean, of course, it's all an illusion anyway, right, it's all the nation, But in particular, this is very important for things like sports. You know, sporting events, you've got people moving around really fast,

You've got a lot of action going on. Um and with the incredible detail that you get with high definition, it can create a lot of artifacts, a lot of blurring. So you want two things. You want a television that can show a very sharp image, and you want television that can show very smooth motion. And that's where the refresh rate comes in. So that means that the three things you really need to concentrate on when you're shopping for televisions. For an HDTV are the lines of resolution.

Depending on the size of the TV. If it's a really really big TV, you want the ten a D. The method of of how it's displaying the image, whether it's interlace or progressive. Progressive is better than interlace. Uh, there's no two ways around that. And then the refresh rate and refresh rate is also very important for three D technology because three D we're going back to showing

two different images alternating between the two very very quickly. UM, and that requires a very fast refresh rate so that you can keep that that transition very smooth. So if you have a display that has a very high refresh rate, then it is better. It's going to be better than showing three D images. And of course here I'm talking mainly about UM ones that use polarized lenses. Uh, you have to use glasses that have a polarized lens as opposed to the old red and blue sets, because any

TV can show the redden blue. I mean, that's that's a little different. You know, you don't have to have a special HD TV to do that, but if you want to do the polarization, then you're gonna need one that has a really good refresh rate. And we actually talked about the different kinds of of three D goggles or glasses, I should say, and uh, like a year ago, Yeah,

like a year ago. That was almost a year nine nine, Okay, And I know this because I answered a listener mail today about three D. Do you want to talk about the the component video cable because I mean, here again, this is something we've talked about in previous podcast. But uh, you know, because of the progressive scan, the the amount of information the cables are actually handled a little differently because you don't have the typical you know, single video cable,

the yellow and the red white yellow. Yeah, that's that is an important distinction progressive scan. Uh, the higher quality of device you have eating video into your television, the better the cables need to be. In the sense that the of types of cables not necessarily better within a type. We had a discussion in another podcast about whether or not expensive cables are worth it. In general, a decent cable is going to perform just as well as a

very high end cable, at least for most people. I guess arguably, if you had amazingly finely tuned human senses that go beyond my own understanding, you might be able to detect the difference between high end and normal. It depends on how long the cable is and a couple, but in general, if you if the if the cable is really well made in the sense that it's really durable,

then that obviously makes a difference too. I mean, you might have two cables that start out working really well and essentially are indistinguishable between the two, and then a year later, one is still performing at that level and the other is slowly kind of fallen apart because it's just a you know, not not as well made. But you don't tend to see like usually you're not going to see a jump in quality based upon the cable. But getting back to component, a component versus a composite cable.

Component cable breaks out the video stream into three separate streams. So each one of those cables is carrying essentially one third of the information necessary to generate the image on your television, and it provides an incredibly sharp picture if you have the right equipment feeding the image into the TV. Yeah, it actually splits out the light and the color yes um, into the three different cables. Yeah, the cables themselves are

colored red, green, and blue. So some people believe that that means that all the red information is carried on one, the green on another, and the blue on the third. It's not the case. Yeah, it's a color. It's just Yeah, it's just so that you plug the right cable into the right socket. It's all that that. That's all that

really indicates. It's not an indication of what color. It tends to carry now the old, the old composite ones that like you said, it's the one yellow, it's the entire video feed, which is not going to be that that sort of high definition experience you want. You can also use h d M I, which will give you the high definition experience. I prefer the component video over the h d M I mainly because component video does not have UM DRM. Yes dr M associated with it.

Digital rights management. Yes, h d M I does have digital rights management associated with it, which means that you may or may not be able to do things like make a legal copy of something for your own benefit because it's using HDMI rather than component But that also does suggest that there there's been talk that movie studios

and manufacturers may stop supporting component video um entirely. They'll just stop creating devices that have component video outputs, forcing you into h d M I, which would mean, you know, that's the convenient way of getting around that whole d D r M loop. So I do not look forward to that day because eventually any electronics device that you purchase you will have to replace sometime. I mean, it's

just not gonna work forever. Um. You know, either it just wears out, or the cat throws up on it, or the kid throws up on the cat and then the cat rubs up against it. It's something there's a lot of vomit involved. That's really pleasant. Thank you so much for that. Yeah, lunch is right after the podcast, folks.

Um not anyway, So for Matt Frederick, Matt Frederick is our guest producer today, Ladies and gentlemen, and I hear him whimpering halfway between laughter and halfway between little sounds being disgusted. Yes, it's great. That's how we know the episode is a success when we when we discussed the producer um, So yeah, that's the that's the whole component versus composite video chord Um. Is there anything else you

wanted to cover about progressive scanning? We pretty much covered the base six and and you know there's of course there's a lot behind the scenes if you're talking about technology about how does this actually work? But just for the regular consumer, the important thing to remember is that little lower case P that is going to be the indication that you're going to get the smoothest, sharpest picture. The P stands for quality. Yes, just look in a mirror and then it's a cue. Um yeah, because the

the eye. Yeah, this is the confusing thing about technology is when you see a number and it's a bigger number than another number, you immediately think, oh, this one has to be better. This is one of those cases where that's not necessarily true. Well, it's easy to market because it's easy for people to understand. That's kind of

going back to the whole megapixel thing with cameras. Yeah, mega hurts that, yes, that's getting of course now it's giga hurts, but yes, yes, go out and get yourself a progressive scan DVD or HD or well blue ray player. That's gonna say, h D DVD, but that's just silly. Don't go out and get one of those people that

that format has been dead for two years now. Um go get a blue ray player again, an HDTV player, get a get a nice component video cord, hook them all up, enjoy that high refresh rate, watch that that high definition movie. Let your jaw hit the floor. Remember, you know, in in two thousand ten this year and we're gonna see some three D content start to come

out on things like the Discovery Channel and ESPN. So you're still want one of those fast televisions, you can watch that and then just just because you have a fast television doesn't necessarily mean it's three D ready either. But we're gonna start seeing those come out hit the market this year too, so they're becoming more affordable though. That's one thing I noticed over the holiday season, you know,

with all the you know, deluge of ads. Yeah, Chris pointed out earlier that a lot of the kind of the value um models of televisions are starting to come out supporting these features. You know, before it was always the leading edge companies like Sony and Panasonic. These are the ones that tend to produce the high end version of televisions, and now we're starting to see the next tier kind of produce their own h D t vs

with a three D capability and other cool goodies. All right, Well, I guess that wraps up our discussion on progressive scan uh and it leads us to a little more listener mail. This listener mail comes from Gabriel, who says, hey, guys, I'm from Brazil and everyone loves your podcast over here. Wow. I wish I knew Portuguese for thank you. I'm quite curious about that in Vidio Home three D monitor. How does it work? Is it worth to worth it to buy one now? Or should I wait for the technology

to develop a little more. Thanks guys, and keep it up well, Gabriel. I actually looked into this a little bit because I wasn't sure what you were referring to. In Video doesn't really make monitors. Now. They do make a software called the Nvidia Home Monitor, but that's meant to monitor your your PC. It's designed to keep tabs on what your computer is doing, how it's performing. Really like, is your CPU performing at peak performance? Do you need

more memory? Do you you know? Do you need more storage? That kind of thing, And it doesn't in a three D environment because in Video has been making graphics cards and glasses that work, uh in you know, in a three D set up on your computer. Now, if you want to run three D software on your computer, what you're gonna need is you're gonna need a computer that runs at a pretty fast clip. It's gonna have to have a good graphics card like in this case we're

talking about. In Nvidia makes several cards that are specifically three D capable. You're gonna need um and a pair of three D glasses. Now, and in Video's case, these are active glasses. They're not polarized. They actually have little electronic shutters in them that open and close. Self asked that you can't even see it. You can. You don't perceive that they're opening and shutting, but they are at

a really fast rate. The monitor is actually displaying two different sets of images timed exactly with the way your glasses are shuttering on and off, you know, each lens alternating. So that's what creates the illusion of a three D image. Um, and the two are SYNCD up together. Right. So you've got the glasses, you've got the the computer running the with the graphics card, and you're gonna need a special monitor.

And in Video actually lists the different kinds of monitors that are compatible with its system because they all have to have a specific kind of refresh rate and ord

of it to work with the Nvidia graphics card. So when you get those three things together, and then of course some software that supports three D, uh, you can you can play games in three D. There's some software like the Nvidio Home Monitor, which, like I said it, all it does is really show you what your computer is doing, like how it's performing, UM, then you can

use that kind of stuff. Having used the Nvidia glasses, I actually got a chance to test drive them at the Consumer Electronics Show back in two thousand nine, I can tell you I was really impressed with them. They performed really well. I played Left for Dead on UM in three D, and I was really impressed with how it performed. In fact, so much so that it is hard for me to play Left for Dead without it being in three D now because it's just not nearly as much fun. So I'd say that the technology is

actually pretty well developed already. I don't know. I mean, I'm sure there will always be improvements, right, I mean, you could always wait and wait and see if something better comes out, but that's always going to be the case.

You might want to wait a little bit longer because by the time this publishes, the Consumer Electronics Show for two thousand and ten will have been over, but there will be new three D monitors and three D video cards coming out, so you may just want to keep an eye out and see what the best thing is

within your own price range. UM. I can tell you that it was a great experience when I played it, and more and more video game UH manufacturers, more and more UH content creators are going to support three D, So at least in the short run, it'll be it is going to be the thing. Whether it lasts, I don't know. It may just be a fad, but I can tell you it's pretty darn cool. But yes, on the on the day we're recording this, we found out that, uh that several people are coming out with full time

three D channels. So I'm sure that just a few days ago we would have said, well, you know, with very little content out there, it's more likely to remain a fad, but you know, that may help push it in the other direction entirely. And one of those two content providers is ESPN and I the two the two markets I think that are going to really propel three D into the common living space will be sports and

video games. Those are the two markets I think that three D is going to to first and strongest, and then eventually it will trickle down into other stuff. You'll get people who want certain three D movies, and we may eventually start to see other kinds of programs created in three D, and then who knows, maybe five years down the line, everything will be three D. Uh. I think that they really need to get past the whole

you need glasses to watch this thing for that to happen. Also, if that does happen, it's really gonna leave out a lot of people who have lost vision in one eye, because you do need the use of both eyes to be able to perceive depth in all the three D systems that exist right now, except I think maybe the lenticular display, because that that does it for you. I think,

I don't know. I don't know. I didn't try closing one eye when we saw you know, we actually had a chance to see one of the uh the TVs with a lenticular film over the screen, which meant that you did not have to wear glasses to see it to see the three D image, you know what. I think there's gonna be some at a consumer electronics show, which at the time of this recording, I'm about to leave to go to it, and then by the time

it publishes I will have already come back. So this is time travel you guys, at the first time we've uh impersonated con travelers. Nope, and it won't be the last. Well, Gabriel, I hope that answers your question. Uh, if I didn't answer your question. If if you're thinking of a very specific product, write me back and send a send a link to it and I'll take a look at it. But from what I could see, that's that's what it

looked like to me. And if any of you have any questions or comments, you got something you want to get off your chest, send it to tech stuff at how stuff works dot com and Chris and I will talk to you again really soon for mora on this and thousands of other topics. Does it how stuff works dot com And be sure to check out the new tech stuff blog now on the house stuff Works homepage, brought to you by the reinvented two thousand twelve camera. It's ready, are you