Why don't HDTV broadcasts fill the screen?

LazBunting · 02-21-2005, 09:57 AM

I have a brand-new direct-view Toshiba 34HFX84 16:9 TV, and a few days ago I had our digital cable service from Comcast (Berkeley/Oakland, California) upgraded to incorporate HDTV. I'm puzzled by a number of things, but for the moment I'll hone in on just one: the HDTV broadcasts, while being delivered apparently in 16:9 format, don't really even come close to filling the screen in "natural" mode. There are black/gray bars on all sides. I can switch the viewing mode to "Theater Wide 2") and this creates a more satisfactory sized image, but it's also clear that this degrades the sharpness a bit.

Is this what is supposed to happen? I understand that when HDTV broadcasters send out SD material, the image is going to be smaller. But I had thought that HDTV material would fill up the screen. My thought is, why did I pay for a 34" screen only to end up with 27" broadcasts?

Is this how it's "supposed" to be, or is something set wrong, either in my cable setup (done by a tech who was fairly shaky on HDTV technology) or my cable box? I know that the cable box and TV both are set for 1080i images.

Thanks for any answers,
Doug

HighdefDoug · 02-21-2005, 10:34 AM

the screen is filled when HD content is sent...thus the 16x9 view, for CBS, ABC, NBC, FOX, this mostly occurs after 8pm and for specific sports viewing events usually on Weekends.

Otherwise, the feed is SD on your HD channel, and gives you the typical 4x3 view since that is the complete content contained in the signal. Your provider can't add the left and right angle views if the signal from CBS is only 4X3 SD. Some networks, some shows, will add the grey or black bars, or even, add a simulated 16x9 bar like on ESPNHD during non HD portions of the show they add the ESPN logo down the bars.

LazBunting · 02-21-2005, 11:13 AM

Thanks for the answer.

But I have to confess that the solution to the problem was embarrassing in its simplicity. Yes, the actual HDTV content was being delivered in diminished form. Really! Why? Because the cable installer for the new HDTV box failed to attach the component cables to the cable box! In other words, he hooked them up to the back of the tv, but NOT to the back of the cable box. This means that the signal to the TV was only a basic coaxial signal, as through the "antenna 0" input option.

I found the component cable, all five plugs worth (three video, two audio) dangling behind the cable box. I plugged them in and, voila! HDTV programming that not only fills the screen but looks like it's supposed to!

RSawdey · 02-28-2005, 05:41 PM

Access your STB setup menu by pressing 'menu' on the remote when the TV is on & the cablebox is off... select 'TV shape = 16:9', 'Y/Pr/Pb = 1080i', '480 override = 480i'. Press 'menu' again to exit, then power up.

If you want true surround, you'll need a digital SPDIF audio connection between the STB and a DD 5.1 decoding amp.

donellyd · 03-02-2005, 10:07 AM

Quote:

Originally Posted by RSawdey

Access your STB setup menu by pressing 'menu' on the remote when the TV is on & the cablebox is off... select 'TV shape = 16:9', 'Y/Pr/Pb = 1080i', '480 override = 480i'. Press 'menu' again to exit, then power up.

I read in a previous thread, a long time ago, that 1080i is not superior to 720p. Also, is there concurrance that 480 override should be set to 480i for best SD viewing.

RSawdey · 03-03-2005, 06:29 PM

1080i is INTERLACED and only 30 frames per second. 720p is progressively scanned and 60 fps. Here's a link to an article about the superiority of progressive...
http://www.atd.net/HDTV_faq.html

How 'override' is set depends on your TV, how it handles zoom & stretch. If your set doesn't use a CRT, you don't need to distort the image to keep the screen filled. If you set 'override' to 'off' then SD will be converted to HD in the STB... and you won't have to mess with 'aspect'. If you do need zoom & stretch for a CRT, try both 480i & 480p to see how your TV handles both.

donellyd · 03-04-2005, 07:49 AM

As always, thanks for your help RSawdey. My tv is the JVD HD-ILA 52Z585, therefore isn't a CRT. Also, I do think I have the 4:3 override set to off. I don't need to stretch the aspect ratio to avoid burn in - just to fill the screen and take advantage of the extra space on either side of the 4:3 pic. I wish the Comcast guy could have done more than connect the RG6 and split - didn't even adjust anything in the menu.

Lanny · 03-04-2005, 12:20 PM

If you have the 4:3 override set to off, you will not be able to use your TV's stretch options. That's why the previous suggestion was for you to try either 480i or 480p.

HughScot · 03-05-2005, 03:41 PM

Quote:

Originally Posted by donellyd

I read in a previous thread, a long time ago, that 1080i is not superior to 720p. Also, is there concurrance that 480 override should be set to 480i for best SD viewing.

If the picture is static it will look better with 1080i than 720p due to the increase in pixels. When watching sports with lots of motion the 720p format should give a better picture due to the the lack of motion artifacts. But much depends on the equipment being used by the network. Watching football on Fox in 720p is not as good as MNF on ABC using 720p. And CBS, which uses 1080i, has improved their signal when broadcasting sports.

RSawdey · 03-05-2005, 04:01 PM

Output of your video sources should be configured for the native resolution of the display, has nothing to do with the format of content. For the HD-ILA should be configured to 720p, CRTs to 1080i. Set & don't change unless you get a different display. If video processing occurs in a device other than the device decoding audio, the video may be delayed and audio sync lost.

If 480 override is set to 480i, then SDTV will be passed to the TV unchanged for upconversion. If set to 480p, the STB will deinterlace & output as EDTV. When set to OFF the STB upconverts 480i to whatever the HD res is set for. Many TV don't let you zoom or stretch an HD signal, so if you want to distort the narrowscreen stuff you'll have to set 480 override to 480i or 480p. You still probably won't be able to zoom a 4:3 upconvert sent on an HD digital channel.

Since DILA is burn proof, most people would prefer to see narrowscreen 4:3 content in the original aspect, undistorted. Most only stretch to prevent screen burn. Are you a big fan of 'Shallow Hal' and love actors that look like they weigh 500 pounds?

donellyd · 03-07-2005, 01:47 PM

Much thanks for the help, everyone. I believe my STB is set up for me. Since I'm not one for mashing and stretching tall, thin people to make them look short and fat, I never mess with with the stretch control. Nothing wrong with 4:3. Just love the 16:9 when I can get it.

RSawdey · 03-08-2005, 03:38 AM

That's like living "Shallow Hal"... hahaha

02-21-2005, 09:57 AM	#1
LazBunting Hi-def novice Join Date: Feb 2005 Location: Berkeley, California Posts: 25	Why don't HDTV broadcasts fill the screen? I have a brand-new direct-view Toshiba 34HFX84 16:9 TV, and a few days ago I had our digital cable service from Comcast (Berkeley/Oakland, California) upgraded to incorporate HDTV. I'm puzzled by a number of things, but for the moment I'll hone in on just one: the HDTV broadcasts, while being delivered apparently in 16:9 format, don't really even come close to filling the screen in "natural" mode. There are black/gray bars on all sides. I can switch the viewing mode to "Theater Wide 2") and this creates a more satisfactory sized image, but it's also clear that this degrades the sharpness a bit. Is this what is supposed to happen? I understand that when HDTV broadcasters send out SD material, the image is going to be smaller. But I had thought that HDTV material would fill up the screen. My thought is, why did I pay for a 34" screen only to end up with 27" broadcasts? Is this how it's "supposed" to be, or is something set wrong, either in my cable setup (done by a tech who was fairly shaky on HDTV technology) or my cable box? I know that the cable box and TV both are set for 1080i images. Thanks for any answers, Doug

02-21-2005, 10:34 AM	#2
HighdefDoug High Definition is the definition of life. Join Date: Nov 2004 Posts: 154	the screen is filled when HD content is sent...thus the 16x9 view, for CBS, ABC, NBC, FOX, this mostly occurs after 8pm and for specific sports viewing events usually on Weekends. Otherwise, the feed is SD on your HD channel, and gives you the typical 4x3 view since that is the complete content contained in the signal. Your provider can't add the left and right angle views if the signal from CBS is only 4X3 SD. Some networks, some shows, will add the grey or black bars, or even, add a simulated 16x9 bar like on ESPNHD during non HD portions of the show they add the ESPN logo down the bars. __________________ Samsung HLP5085DLP 600 Watt Sony Home Theater PS2, Motorola 6412 Comcast HD DVR Toshiba 5970 HDMI DVD

03-04-2005, 07:49 AM	#7
donellyd High Definition is the definition of life. Join Date: Sep 2004 Posts: 31	Comcast needs to better-train their STB installers... As always, thanks for your help RSawdey. My tv is the JVD HD-ILA 52Z585, therefore isn't a CRT. Also, I do think I have the 4:3 override set to off. I don't need to stretch the aspect ratio to avoid burn in - just to fill the screen and take advantage of the extra space on either side of the 4:3 pic. I wish the Comcast guy could have done more than connect the RG6 and split - didn't even adjust anything in the menu.

03-05-2005, 04:01 PM	#10
RSawdey Mr. Wizard Join Date: Feb 2005 Location: Ferndale, Michigan Age: 62 Posts: 5,981	Output of your video sources should be configured for the native resolution of the display, has nothing to do with the format of content. For the HD-ILA should be configured to 720p, CRTs to 1080i. Set & don't change unless you get a different display. If video processing occurs in a device other than the device decoding audio, the video may be delayed and audio sync lost. If 480 override is set to 480i, then SDTV will be passed to the TV unchanged for upconversion. If set to 480p, the STB will deinterlace & output as EDTV. When set to OFF the STB upconverts 480i to whatever the HD res is set for. Many TV don't let you zoom or stretch an HD signal, so if you want to distort the narrowscreen stuff you'll have to set 480 override to 480i or 480p. You still probably won't be able to zoom a 4:3 upconvert sent on an HD digital channel. Since DILA is burn proof, most people would prefer to see narrowscreen 4:3 content in the original aspect, undistorted. Most only stretch to prevent screen burn. Are you a big fan of 'Shallow Hal' and love actors that look like they weigh 500 pounds? Last edited by RSawdey; 03-05-2005 at 04:07 PM.

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02-21-2005, 11:13 AM	#3
LazBunting Hi-def novice Join Date: Feb 2005 Location: Berkeley, California Posts: 25	Thanks for the answer. But I have to confess that the solution to the problem was embarrassing in its simplicity. Yes, the actual HDTV content was being delivered in diminished form. Really! Why? Because the cable installer for the new HDTV box failed to attach the component cables to the cable box! In other words, he hooked them up to the back of the tv, but NOT to the back of the cable box. This means that the signal to the TV was only a basic coaxial signal, as through the "antenna 0" input option. I found the component cable, all five plugs worth (three video, two audio) dangling behind the cable box. I plugged them in and, voila! HDTV programming that not only fills the screen but looks like it's supposed to!

02-28-2005, 05:41 PM	#4
RSawdey Mr. Wizard Join Date: Feb 2005 Location: Ferndale, Michigan Age: 62 Posts: 5,981	Access your STB setup menu by pressing 'menu' on the remote when the TV is on & the cablebox is off... select 'TV shape = 16:9', 'Y/Pr/Pb = 1080i', '480 override = 480i'. Press 'menu' again to exit, then power up. If you want true surround, you'll need a digital SPDIF audio connection between the STB and a DD 5.1 decoding amp.

03-03-2005, 06:29 PM	#6
RSawdey Mr. Wizard Join Date: Feb 2005 Location: Ferndale, Michigan Age: 62 Posts: 5,981	1080i is INTERLACED and only 30 frames per second. 720p is progressively scanned and 60 fps. Here's a link to an article about the superiority of progressive... http://www.atd.net/HDTV_faq.html How 'override' is set depends on your TV, how it handles zoom & stretch. If your set doesn't use a CRT, you don't need to distort the image to keep the screen filled. If you set 'override' to 'off' then SD will be converted to HD in the STB... and you won't have to mess with 'aspect'. If you do need zoom & stretch for a CRT, try both 480i & 480p to see how your TV handles both.

03-04-2005, 12:20 PM	#8
Lanny High Definition is the definition of life. Join Date: Sep 2004 Location: Winthrop, MA Posts: 421	If you have the 4:3 override set to off, you will not be able to use your TV's stretch options. That's why the previous suggestion was for you to try either 480i or 480p.

03-07-2005, 01:47 PM	#11
donellyd High Definition is the definition of life. Join Date: Sep 2004 Posts: 31	Much thanks for the help, everyone. I believe my STB is set up for me. Since I'm not one for mashing and stretching tall, thin people to make them look short and fat, I never mess with with the stretch control. Nothing wrong with 4:3. Just love the 16:9 when I can get it.

03-08-2005, 03:38 AM	#12
RSawdey Mr. Wizard Join Date: Feb 2005 Location: Ferndale, Michigan Age: 62 Posts: 5,981	That's like living "Shallow Hal"... hahaha