What source for HD? Built in tuner or external STB?
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HDTV Aspect Ratio
I've just received a 19" Toshiba HDTV LCD set, which will replace a 14" RCA CRT as the main set in this bedroom.
One issue has me puzzled. On digital channels, broadcasting an image in the standard, non-widescreen aspect ratio, it looks almost square on this monitor. Image appears slightly squeezed in as a result.
One local station, WTVZ, broadcasts an HD signal on its main carrier, and an SD simulcast on a substation. On the SD digital subtation, a non-widescreen image on this screen measures 13 1/4 x 10". In comparison, the same program on the main HD station measures 12 x 10." I've noticed the same squeezed-in effect on other HD channels in this area broadcasting a standard aspect ratio image.
Is this to expected from an HDTV set, or does this set have a problem that needs to be addressed by a technician? It's not observed when viewing the image from my standard definition Dish receiver (13 1/4 x 10"), nor is it observed with standard aspect ratio DVDs. This has only been seen with over the air, standard aspect ratio digital images.
Picture size can be altered with the Toshiba for over the air digital HD channels, but the choices are limited to two--standard ratio and a "fill the screen" ratio which loses much of the image.
One issue has me puzzled. On digital channels, broadcasting an image in the standard, non-widescreen aspect ratio, it looks almost square on this monitor. Image appears slightly squeezed in as a result.
One local station, WTVZ, broadcasts an HD signal on its main carrier, and an SD simulcast on a substation. On the SD digital subtation, a non-widescreen image on this screen measures 13 1/4 x 10". In comparison, the same program on the main HD station measures 12 x 10." I've noticed the same squeezed-in effect on other HD channels in this area broadcasting a standard aspect ratio image.
Is this to expected from an HDTV set, or does this set have a problem that needs to be addressed by a technician? It's not observed when viewing the image from my standard definition Dish receiver (13 1/4 x 10"), nor is it observed with standard aspect ratio DVDs. This has only been seen with over the air, standard aspect ratio digital images.
Picture size can be altered with the Toshiba for over the air digital HD channels, but the choices are limited to two--standard ratio and a "fill the screen" ratio which loses much of the image.
1 - 7 of 7 Posts
Hi there
I can view OTA HDTV on my PC monitor, and can see a variation in the 4:3 image width within the 16:9 viewing window. There's a control panel of almost the same width as the 4:3 pillar-boxed image just below that video image, so it's easy to see the variation. The variation seems to depend on the broadcaster. I wouldn't worry about it.
BTW it is not "SD digital substation" or "main carrier". They are all subchannels from one digital broadcasting "station".
Regards
edit:
When you write "squeezed-in effect", do you mean a difference in image width (i.e. cropping), or geometric distortion? I've only seen cropping differences, and not noticed any geometric distortion.
I can view OTA HDTV on my PC monitor, and can see a variation in the 4:3 image width within the 16:9 viewing window. There's a control panel of almost the same width as the 4:3 pillar-boxed image just below that video image, so it's easy to see the variation. The variation seems to depend on the broadcaster. I wouldn't worry about it.
BTW it is not "SD digital substation" or "main carrier". They are all subchannels from one digital broadcasting "station".
Regards
edit:
When you write "squeezed-in effect", do you mean a difference in image width (i.e. cropping), or geometric distortion? I've only seen cropping differences, and not noticed any geometric distortion.
WH,
I think you may be gettiing confused by the fact that all HD resolution broadcasts especially day time shows are not filmed with HD widescreen cameras.
When they are not the broadcaster adds black/blue side pillers as part of the HD resolution image so as not to distort the 4:3 aspect ration SD image in the center of the screen.
When a broadcaster is using a HD widescreen camera such as in prime time or major sports such as NFL football they do what is called "center cut" the image so that it can be transmitted without distortion on their SD analog channel.
You may notice that almost all programs "filmed" with widescreen camera for use on HD channel have no meaningfull content on the sides. This is so that when ceter cut no meaningfull content is lost.
I think you may be gettiing confused by the fact that all HD resolution broadcasts especially day time shows are not filmed with HD widescreen cameras.
When they are not the broadcaster adds black/blue side pillers as part of the HD resolution image so as not to distort the 4:3 aspect ration SD image in the center of the screen.
When a broadcaster is using a HD widescreen camera such as in prime time or major sports such as NFL football they do what is called "center cut" the image so that it can be transmitted without distortion on their SD analog channel.
You may notice that almost all programs "filmed" with widescreen camera for use on HD channel have no meaningfull content on the sides. This is so that when ceter cut no meaningfull content is lost.
Ken, it's the unit's built-in tuner. I can send a signal from my Zenith digital converter to the set, and it looks fine...no squeezed-in effect.
After doing a bit of searching last night, I discovered that I'm the owner of a set whose aspect ratio is actually 16:10 instead of the expected 16:9. I'm wondering now if this may have something to do with it. After checking specs for other 19" LCD sets, I noticed that they all seem to have 16:10 ratios, regardless of brand.
Quote:
Originally Posted by Ken H /forum/post/15408021
What source for HD? Built in tuner or external STB?
Ken, it's the unit's built-in tuner. I can send a signal from my Zenith digital converter to the set, and it looks fine...no squeezed-in effect.
After doing a bit of searching last night, I discovered that I'm the owner of a set whose aspect ratio is actually 16:10 instead of the expected 16:9. I'm wondering now if this may have something to do with it. After checking specs for other 19" LCD sets, I noticed that they all seem to have 16:10 ratios, regardless of brand.
Walford, thank you for the response and the advice. It's not the standard aspect ratio appearance that's creating confusion in this case...it's a noticeable difference in the aspect ratio when viewing a 4:3 image on a digital HD channel, versus it's analog or digital SD counterpart. The image is noticeably narrower, measuring 12 x 10 on this set, versus 13 1/4 x 10 on a digital channel's analog counterpart. People's faces, etc.. have a compressed appearance as a result...i.e., someone's face that might appear round, normally, will have a bit of an oval appearance on this set.
After a bit of additional reading in the Toshiba last night, I've come to the conclusion that I'm only seeing this on channels broadcasting in true high definition. As it turns out, this 19" set has a 16:10 aspect ratio, instead of the expected 16:9...I'm wondering now if this is the culprit.
There is at least a workaround that's effective, which I may have to live with--viewing 4:3 source material through my Zenith digital converter, bypassing the set's built-in tuner. The image looks fine that way, no "squeezed-in" effect.
Quote:
Originally Posted by walford /forum/post/15408115
WH,
I think you may be gettiing confused by the fact that all HD resolution broadcasts especially day time shows are not filmed with HD widescreen cameras.
When they are not the broadcaster adds black/blue side pillers as part of the HD resolution image so as not to distort the 4:3 aspect ration SD image in the center of the screen.
When a broadcaster is using a HD widescreen camera such as in prime time or major sports such as NFL football they do what is called "center cut" the image so that it can be transmitted without distortion on their SD analog channel.
You may notice that almost all programs "filmed" with widescreen camera for use on HD channel have no meaningfull content on the sides. This is so that when ceter cut no meaningfull content is lost.
Walford, thank you for the response and the advice. It's not the standard aspect ratio appearance that's creating confusion in this case...it's a noticeable difference in the aspect ratio when viewing a 4:3 image on a digital HD channel, versus it's analog or digital SD counterpart. The image is noticeably narrower, measuring 12 x 10 on this set, versus 13 1/4 x 10 on a digital channel's analog counterpart. People's faces, etc.. have a compressed appearance as a result...i.e., someone's face that might appear round, normally, will have a bit of an oval appearance on this set.
After a bit of additional reading in the Toshiba last night, I've come to the conclusion that I'm only seeing this on channels broadcasting in true high definition. As it turns out, this 19" set has a 16:10 aspect ratio, instead of the expected 16:9...I'm wondering now if this is the culprit.
There is at least a workaround that's effective, which I may have to live with--viewing 4:3 source material through my Zenith digital converter, bypassing the set's built-in tuner. The image looks fine that way, no "squeezed-in" effect.
When pillarboxing 4:3 (aka 12:9) content to 16:9 some broadcasters will simulate overscan cropping of the left and right of the 4:3 frame, making it appear narrower. This is because SD content often has quite ragged picture edges which is normally hidden by overscan on a 4:3 SD display. If the full 4:3 width image was pillarboxed with no cropping, these ragged edges would be very visible - and you might see keying errors, DVEs drop into circuit etc. (Not helped by the digital and analogue picture widths being slightly different in SD)
Many HDTVs still have overscan, so the top and bottom of the pillarboxed video is still cropped by the TV, so some broadcasters replicate this left and right. If you watch on a display with little or no overscan top and bottom you end up with a narrower image.
(Ignoring also the fact that some may pillarbox to 14:9 rather than 12:9 to give you a wider image at the expense of cropping top and bottom. This is common on SD 16:9 channels in the UK)
Many HDTVs still have overscan, so the top and bottom of the pillarboxed video is still cropped by the TV, so some broadcasters replicate this left and right. If you watch on a display with little or no overscan top and bottom you end up with a narrower image.
(Ignoring also the fact that some may pillarbox to 14:9 rather than 12:9 to give you a wider image at the expense of cropping top and bottom. This is common on SD 16:9 channels in the UK)
1 - 7 of 7 Posts
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