What does NATIVE resolution (display) mean for a TV?

[hhamzeh]

Hi there,

I am wondering how TV native resolution works? Most of HDTV have 480i, 480p, 720p, 1080i display but depends on the brand and model, they have defferent native resolutions (i.e. 720p).

Q1- Does a native resolution of 720p means that regardless of input signal (i.e. 480i or 1080i) TV will always convert the signal to 720p?

Q2- If my DVD Player output is 480p, is there any option on the TV that DO not upconvet the input signal?

Q3- Does upconversion (i.e. from 480p to 1080i) improve image quality?

Thanks.

[manono]

Hi-

Q1-Yes.

Q2-No. If you have a fixed pixel display, then either the DVD player or the TV will have to upscale it to the native resolution of the TV.

Q3-Having one such player myself, I like to think it does. I guess it's a question of which does a better job of upscaling, the player or the TV. It also helps if the player upscales to the same resolution as the TV. There are only a few players that can set a custom resolution, so for TV sets that need, for example, 768p, you often can't achieve 1:1 pixel mapping.

[hhamzeh]

Thanks manono,

What about if my TV is not a fixed pixel display (i.e. Sony 34" CRT HDTV),

Would it convert the 480p input signal to 1080i or it would display the picture as 480p?

Does a CRT HDTV has a native resolution like the fixed pixel display TVs?

Thanks.

[manono]

Hehe, why were you talking about 720p native resolution TV sets then? I don't know anything about how Hi-Def CRTs work. But for them though, if you get an upconverting DVD player connecting over DVI or HDMI, the advice is usually to try the different output resolutions and see which looks best on the TV set. I have a 720p Samsung, and 720p over DVI out of my Oppo looks great, and slightly better than 480p, and 1080i.

[gshelley61]

You probably won't be able to see any difference between the 480p, 720p and 1080i settings using a scaling DVD player... direct view CRT's are very forgiving displays and don't generally benefit from that technology in the same way that large, fixed-pixel digital displays (plasma, DLP, LCD, etc.) do.

[edDV]

Fixed pixel displays and variable pixel CRT's optimize differently. Fixed pixel displays (e.g. LCD, plasma) are natively progressive. Everything needs to be deinterlaced (in hardware) and scaled to the fixed resolution. The scaling doesn't hurt the picture much but the deinterlacing can create serious artifacts and motion distortions. Deinterlacers are getting better with each generation.

CRT HDTV monitors usually handle 480i and 1080i directly without deinterlace. Most will handle a 480p connection directly with progressive display, some will handle 720p progressive display without conversion. Display resolution is limited by the dot pitch of the CRT. Even though 1920x1080i is being scanned to the back of the shadow mask, actual display from the front is usually between 800x600 to 960x720. This is adequate for a 34" or less screen unless you are putting your nose on it.

Replaying your questions for CRT.

Q2- If my DVD Player output is 480p, is there any option on the TV that DO not upconvet the input signal?

Many CRT models allow direct 720x480p display with 480 lines scanned only over the 16x9 image. the black bars are not scanned.

Q3- Does upconversion (i.e. from 480p to 1080i) improve image quality?

Not usually. Progressive 480p/58.94 can look better than upscaled interlace 1080i/29.97. Some sets use single fields of 1080i to make a progressive 540p/29.97 display.

[edDV]

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