View Full Version : Questions on Broadcast formats


Marco Wagner
August 4th, 2005, 08:56 PM
I recently got a plasma widescreen EDTV (480p V x 852 H) + digital HD service and was wondering about the different formats i have to choose from.

My HD channels - should I watch them in 1080i or 720p or 480p? 720p looks nice, do most HD use progressive?

My regular channels - 480i or 480p or 720p?

I was under the assumption that most channels (SD) broacast at 480i. My TV will display 480p, 480i, 720p, and 1080i signals. Just a bit overwhelmed by the options after having a 4:3 SD forever....

If my assumption is right and most SD is 480i will viewing it in 480p or 720p make any difference?

Thanks in advance.

Matt Ockenfels
August 5th, 2005, 12:00 AM
I'd just use what looks best to you!

Cheers,

-Matt

Mike Teutsch
August 5th, 2005, 05:50 AM
You didn't say what you bought, but most TVs automatically detect what signal is incoming and then convert it to what it can displayed. In other words, you don't select the viewing format, except for normal, wide, or zoom for example. What does the manual say?

Mike

Boyd Ostroff
August 5th, 2005, 06:35 AM
Mike is right, you won't really have a choice of what format to pick. Your manual will have specs for what formats are accepted. But just about any new set will decode all the current formats and properly scale them to your screen.

There should be a button on your remote which display info about the current channel in a window on the screen. This will tell you whether you're watchng a 1080i or 720p HD channel or a 480i digital SD broadcast. I suspect these are the only types you'll encounter on your cable, but not sure since I don't subscribe to the digital service myself.

Plasma screens (assuming that's what you have) are progressive by their nature, so an interlaced signal gets internall converted for display. If you're watching a DVD you can check the specs on the package to see if it's progressive. Most newer DVD players can automatically detect this, but some require you to push a button to go into progressive mode. Some older players don't take advantage of progressive scan DVD's.

Enjoy your new screen; the reality is that you don't actually need to understand much of this stuff and it will correctly make these decisions for you.

Steve House
August 5th, 2005, 07:51 AM
Just FYI - at least some HD converter boxes, such as the Motorola DCT 6208 that my cable supplier offers, allows you choose between 480p and 480i as the preferred format to send digital SD signals to the component video outs. My particular TV, a 57" Sony, line doubles either one to 960i.

Marco Wagner
August 5th, 2005, 10:01 AM
EXACTLY! I DO have a choice from my HD converter box. That is why I ask, otherwise with DVDs and other inputs I only have the 16:9, 4:3, and zoom choice through the TV's menu. My choices are broad: 480p standard, 480p wide, 480i, 720p, and 1080i. My HD channels look pretty good in 720p. My question what about the SD channels, 480p or 480i?

Mike Teutsch
August 5th, 2005, 10:06 AM
Probably stick with progressive, but again that is only out of your box and the TV will make whatever conversion it needs to. It will have to downres all as the TV is not very high resolution. The Plasma should look pretty darn good in all settings.

Mike

Duane Smith
August 5th, 2005, 12:32 PM
No matter what signal you feed your TV, it's going to output 480p, since it's a native progressive-scan (p) device, with SD (480) resolution. Anything greater than 480p that you feed it will just get DOWNCONVERTED to 480p anyways.

The good news is that on plasma screens, an ED model often looks *better* with SD (and of course progressive DVD) material than an HD model plasma will...
http://www.plasmatvbuyingguide.com/plasmatv/plasmatv-highdefinition.html
...but naturally, HD material will look better on an HD plasma than an ED plasma.

I'd assume that the reason the 720p setting looks best is because it's natively progressive, as is your TV itself, whereas normal NTSC broadcast is in 480i (even if you set your "box" to 480p, it still started as 480i material, so it's not exactly "optimal").

Ultimately, the proof is in the pudding...or rather, your eyes.

Boyd Ostroff
August 5th, 2005, 12:37 PM
Yeah, I think any SD broadcasts you can tune in will be natively 480i. So if you choose 480p the cable box is deinterlacing them. As Duane says, your plasma screen must deinterlace 480i also, so try it each way and see if one looks better than the other. It probably comes down to how good a scaler the box has.

Marco Wagner
August 5th, 2005, 06:25 PM
Thanks for all the suggestions y'all, I am at home now and ready to play with some settings. One last question: Are the HD broadcasts progressive?

Boyd Ostroff
August 5th, 2005, 06:29 PM
Like I said, look at your instructions. The remote should have a function that displays all that info on your screen. But I think you'll find HD is either 720p or 1080i.

Marco Wagner
August 5th, 2005, 06:39 PM
Yeah i have looked and am looking again right now, but no button that displays that other than "display" which only shows what you are feeding it and the input type. Only a "wide" button that allows me to change from 4:3 to 16:9 to Zoom1 and Zoom2. 720p seems to look best on HD channels. 480p looks best on non HD so far. I haven't bought composite cables for my progressive dvd player yet. My TV requires DVI for PIP, I am currently using composites. DVI is supposed to be better is it not? Gotta get that cable tonight.

Boyd Ostroff
August 5th, 2005, 06:58 PM
I haven't bought composite cables for my progressive dvd player yet

I hope you mean 'component' and not composite. Composite is low resolution, like a cheap VCR, the yellow video cable is usually bundled with a red and white audio cable. Component cables should give you very good quality and consist of a red, blue and green connector for the video. You will need separate cables (red and white) for your audio.

DVI should be better, if your DVD player supports it (only the newest ones will probably). The latest interface is called HDMI however. But on an EDTV I suspect you won't see much difference between these and component.

I'd be surprised if there isn't some function on the tv which can display what sort of signal it's decoding, but maybe you're right. It may be that mine only does this since I don't have a cable box. BTW, what sort of connection do you have between the cable box and the TV? DVI or component would be good for that too.

Mike Teutsch
August 5th, 2005, 07:14 PM
Remember that your TV is EDTV and not HDTV. The article, that I posted the link to below, will help you understand and is very good.

Enjoy your new toy!

Mike

http://www.projectorcentral.com/hdtv_edtv.htm

Marco Wagner
August 5th, 2005, 07:55 PM
Sorry I meant component cables, 3 for video, and yes the two separate for audio. Right now the component cables are going from the cable box to the TV. Old school composites from the DVD, until I get some components for it. I am going to purchase a DVI to DVI later next week as both the box and the TV support DVI, no HDMI though, darn.

Yes the plasma looks wonderful, got it at a grand opening at an electronics store for $1499USD, the HD model which had a very low brightness and contrast ration was $1899. Mine has 4000:1 contrast and 1000 brightness. Considering HD is still newer and not HUGE on the broadcast and DVD market yet, I can live with ED.

Duane Smith
August 6th, 2005, 05:16 PM
For those who haven't seen one, a high-contrast ED Plasma looks SURPRINGLY good. A good friend of mine has one and to be honest it shocked me how good progressive scan DVD movies looked on it. It was in many way superior to my direct-CRT HDTV.

Now having said that....there is absolutely NO comparison between watching true HD material on an true 1080-capable HDTV and then watching it on an ED Plasma. The HD will simply blow the doors off the ED plasma; there's no denying how much better the 5x increase in resolution looks.

The best-of-both-worlds would be a high-quality 1080-capable HD plasma, but they're insanely expensive. So given a choice between an affordable high-quality ED plasma -or- an affordable low-quality HD plasma, I'd choose the ED model.

Or if you really want HD (like I did), just step away from the Plasma models entirely and look at a different technology (DLP is a great alternative).

Mike Teutsch
August 6th, 2005, 05:29 PM
Got my 50" Sony LCD HDTV two weeks ago, and love it. Built in HD tuner, and in-puts for all, 480P, 480I, 720P, and 1080I. My old TV was an HDTV, but only could display over the air HD. No inputs at all. I finally get to see what my JVC JY-HD10U looks like.

Mike

Boyd Ostroff
August 6th, 2005, 05:36 PM
I got a Panasonic Vierra ED plasma screen last winter when my Sony WEGA 4:3 tube set died. I agree, they look phenomenal with DVD's - actually better than the HD screens since there's less scaling involved. And the 4000:1 contrast ratio is terrific and is something that LCD's can't provide.

There is a huge price difference in the HD plasmas and the ED screens are a good value (if you want plasma). I'd say that viewing an HD broadcast on the ED screen does look a bit sharper than a DVD, but I'm sure it's nothing like true 1920x1080. Regardless, my plasma screen has completely met my expectations and I'll be happy with it for a number of years. If I feel HD-starved I'll go stare at my 22" Samsung LCD TV (1280x720) or Apple 23" Cinema Display (1920x1200)...

Duane Smith
August 6th, 2005, 07:41 PM
I agree, they look phenomenal with DVD's - actually better than the HD screens since there's less scaling involved.

The "less scaling" is precisely why an ED Plasma looks better than an HD Plasma (or really, HD anything) when viewing a DVD. Believe me, my buddy's 40-some-odd-inch ED Plasma, coupled with his awesome audio setup, is just about the PERFECT setup for viewing DVDs. It certainly makes me jealous...and I've got a real HDTV! :-P

Jack Zhang
August 7th, 2005, 03:36 PM
The big thing that Sony should develop would be a professional progressive scan tape format, my guess is it would use the MPEG-IMX protocol to carry a 480p60 or 576p50 signal on a regular IMX tape. If they made this format, expect really HQ 4:2:2 60p or 50p from your new local channels or the major networks!

Marco Wagner
August 10th, 2005, 05:50 PM
So far I have no complaints. W3 watched the nascar race on sunday in full HD glory. I had a couple other SD TVs on in the house so we wouldn't miss the action, was kind of a party. You could totally tell the difference when I switched the plasma to the SD channel vs the HD. We watched it in 1080i with no issues. I am still testing 720p vs 1080i, I guess it just depends on what the program is shot in to determine the best viewing res. Love it though! Thanks for all of your help. Now If I could just figure out the picture-in-picture! I want to view to separate cable channels at once, haven't quite figured that out yet. Both pictures end up being the same channel, kinda lost as to how to split them.