Need resolution clarification!!

[madmac]

Ok all....I think I know the answer to this but just to be sure, I need to ask all our experts here on the forum....

If you have a pure 1080P HDTV and you are watching over the air DTV broadcasts.....If the resolution on your display reads 720P.....then that is the native resolution of the broadcast only.... but you're TV is upconverting that signal to it's native resolution of 1080P correct?. Same goes for 1080i resolution correct???.

Just want to be sure!!!!??

[Hdale85]

Well 1080i isn't upconverted. It's a 1920x1080 resolution. But for 720p yes it would be scaled to your TV's native res.

[madmac]

Hummm????.....I'm not so sure of that!!. I'm pretty sure that everything is displayed in 1080P. If the signal is not in that res, then the TV scales it to that res. That's why my BD and Oppo player look so good on my display, because it's giving the TV what it wants and it is not having to upscale the picture itself.

However....I would like to hear some other opinions from other members.

[mjb]

The OSD shows the source signal resolution. 1080 will map 1:1 on a 1080 screen, anything else will have to be scaled somewhere. Depending where, you could be looking at a 480 display with a superimposed OSD telling you its 1080!!

[Hdale85]

Umm....I just said it scales everything that's not 1920x1080 to 1920x1080. A 1080i resolution is 1920x1080, I know people think it's the same as 720p but that's a myth it really isn't.

[mjb]

Umm....I just said it scales everything that's not 1920x1080 to 1920x1080. A 1080i resolution is 1920x1080, I know people think it's the same as 720p but that's a myth it really isn't.

Exactly right! If the source isn't 1920x1080 (1080i OR 1080p) the signal WILL be scaled somewhere (usually in the display itself) to fit the 1920x1080 physical pixels of the panel. Even then it might not be 1:1 due to overscan, but thats another story.

[madmac]

It's funny though that when the TV is showing 720P, 1080i, or 1080P that the image DOES look different to me. 1080P being the best. I like 720P better than 1080i. Looks better, smoother and warmer to my eyes.

[Hdale85]

More then likely your processor that's in the TV isn't all that great. A lot of TV's have this issue, so anything other then Native resolution doesn't look great. One of the big downfalls of newer TV's is de-interlacing I'd say, because it doesn't need to be done as much. To make 1080i look it's best you need a pretty decent processor to de-interlace the image. On my 1080i RPTV 1080i looks great

[Chris D]

Some people definitely prefer 720p over 1080i or vice versa. I know for myself, several years ago while HDTV cameras were only using one or the other, I could tell a difference particularly with action material like football games. I honestly can't remember which one looked better at the time. Nowadays, TV studios have 1080p cameras.

[Hdale85]

Well, like I said it all comes down to processing and what your native resolution is. If you have a nice processor that can handle the resolutions properly it'd likely be a lot harder to tell a difference.

[impala454]

Mac, how were you comparing 720p to 1080i? Doesn't seem like you could really do a direct comparison. They'd be different feeds from different source material.

[madmac]

Mac, how were you comparing 720p to 1080i? Doesn't seem like you could really do a direct comparison. They'd be different feeds from different source material.

True,,,,,, but I've been looking at my monitor for quite some time and,,, Fox broadcasts their material in 720P and I find it looks slightly better than....say NBC or CBS that broadcasts their material in 1080i..... Mind you, it all looks very nice..... but I find that 720P looks more 'cinematic' in character.....warmer in an analog audio kinda' way....but.....high def nonetheless!!. It's nice !! :T

[impala454]

In the end I think the source material is what it's all about though. It's a bit of a stretch to look at different material and decide quality based on that. Kind of like listening to two different recordings on two different audio systems and deciding which audio system sounds better.

I always recall (back when I had cable ) stuff like Discovery HD and HDNET being absolutely hands down the most amazing picture quality and those were 1080i. And why wouldn't it be? There's twice as many pixels on the screen

[Hdale85]

Yes some of the best stuff on HD is in 1080i, Jay Leno was always a standard of sorts and it's on a 1080i broadcast.

[madmac]

We are all truly spoiled now compared to when we were kids!. It all looks amazing as far as I'm concerned!!. R.I.P. VHS !!!

[Ovation]

If your TV does not de-interlace particularly well (and many don't), then 720p might well look better than 1080i (the TV is only scaling 720p, not de-interlacing on top of that). Just a thought.

Anything other than a signal that matches the resolution of the display is either scaled or de-interlaced or both. The quality of each of those separate tasks (whether done together or singly) has an important effect on image quality.

[madmac]

If your TV does not de-interlace particularly well (and many don't), then 720p might well look better than 1080i (the TV is only scaling 720p, not de-interlacing on top of that). Just a thought.

Anything other than a signal that matches the resolution of the display is either scaled or de-interlaced or both. The quality of each of those separate tasks (whether done together or singly) has an important effect on image quality.

I believe you are correct there!! :T

[aud19]

Hummm????.....I'm not so sure of that!!. I'm pretty sure that everything is displayed in 1080P. If the signal is not in that res, then the TV scales it to that res. That's why my BD and Oppo player look so good on my display, because it's giving the TV what it wants and it is not having to upscale the picture itself.

However....I would like to hear some other opinions from other members.

You'd be confusing scaling and de-interlacing there

As Dougie eluded to, a 1080i signal IS 1920x1080 but as it's interlaced, it needs to be de-interlaced to be displayed on your native 1080p display, not scaled. Technically, so long as your source or TV is doing the de-interlacing properly (And their both the same bit rate etc) there should be virtually NO difference between a 1080i and 1080p signal on your display.

That tells me you're either noticing the difference in bit rate from 1080p BluRay discs compared to highly compressed cable/satellite signals and/or your source/TV is not de-interlacing properly and/or does a better job scaling 720p than de-interlacing 1080i.

As for 720p vs 1080i... the key to it is again, the de-interlacing quality (given equal bit rates, compression etc). Displays with average quality (poor) de-interlacing will have much smoother motion in a 720p signal as your not dealing with interlacing artifacts which are much more noticeable with motion. Hence why most sports channels use it over 1080i. Still/slow moving pictures tend to look better in 1080i with it's higher perceived resolution however. So largely stationary/slow things like news, sitcoms, dramas etc tend to be broadcast in it. The actual resolution of both in a given frame is actually quite similar. 1280x720 = 921,600 and 1920x540 = 1,036,800...not far apart.

[impala454]

The actual resolution of both in a given frame is actually quite similar. 1280x720 = 921,600 and 1920x540 = 1,036,800...not far apart.

I see your point but I don't think you can really sum it up in such a simple calculation. In terms of pixels you perceive the image is still 1920x1080, and more than double the pixels on the screen than 720p. It's not about what is actually on the screen so much as what ends up inside your brain. Technically, comparing a 1080i and 1080p source which doesn't have a lot of fast motion would look identical to the viewer (or heck, even a completely still image ). With quickly moving source material then sure you could start to perceive artifacts but that doesn't diminish the resolution of the entire image.

Likewise, say you were able to ramp up the frame rate (from the source) to 600 fps. That doesn't equate to a 1280x720x10 resolution image. The resolution stays the same.

I agree with you that I figure mac is probably moreso seeing the artifacts due to bandwidth and/or compression than perceiving the interlaced frames individually.

It will be interesting to see where this goes in the future, as we're already pretty much on the limit of perceivable frames, and probably pretty close to whatever dot size a human can perceive as well. At some point we're bound to get to a "final" format that cannot be improved on.