Does 720p = 1080i

[-Hibikster-]

Some people say yes, others say no...can someone please clarify for me the difference if there is one? I mean on many electronic devices it usually gives you the option to select one or the other, so I'd think that there is a difference...but I'm not sure.

 

[Kristian Meller]

Of course there's a difference. 720p is 1280*720 progressive and 1080i is 1920*1080 interlaced. Different resolutions and different methods of storing the images.

 

[Metal Slugnuts]

No.

1080i ~ 540p split into two different sets of scanlines, just like 480i ~ 240p.

I'd steer clear of interlaced alltogether if you can help it.

 

[Magician]

I see image ghosting whenever I've tried 1080i.

I prefer 720p myself.

 

[evil wasabi]

Some people say yes, others say no...can someone please clarify for me the difference if there is one? I mean on many electronic devices it usually gives you the option to select one or the other, so I'd think that there is a difference...but I'm not sure.

my understanding is that the interlacing fills in the blanks between the scanlines, so the picture may not be as accurate as one would prefer. As such, 720p would be preferable to 1080i.

 

[Metal Slugnuts]

The thing about all interlaced pictures that I can't stand is that motion combing shit (especially on 480i). Especially if you look up close it makes the image look jerky and terrible.

Goddamn I need a new TV...can't wait until my comp monitor arrives so I can have some 360 VGA love.

EDIT: a link describing what I was talking about
http://neuron2.net/LVG/interlacing.html

 

[Deuce]

1080i ~ 540p split into two different sets of scanlines, just like 480i ~ 240p.

That's only partially true, and depends on the video source.

I'd steer clear of interlaced alltogether if you can help it.

Seconded.

 

[Metal Slugnuts]

That's only partially true, and depends on the video source.

I know, I casually read about this kind of tech info but I'm not an expert by any means. That's just my basic understanding of it.

 

[famicommander]

720p is a progressive signal. 1280x720=921,600 pixels on screen at a given time.
1080i is an interlaced signal, meaning only half the information is on screen at a given time. 1920*1080/2=1,036,800 pixels on screen.

So 1080i actually has more information on screen at any given point in time, but due to its interlaced nature you might get things like motion blur.

For me, it really depends on the source. My cable and video games tend to look better in 720p, but I've noticed that the majority of my Blu Ray movies look better in 1080i.

Another thing to consider is the size of your screen. For example, on a 32 inch television it is impossible to tell the difference between 720p, 1080i, and 1080p unless you're ~4.5 feet or closer to your screen.

 

[Neo Ash]

IMO if the TV is around 42" or smaller it will be very difficult to tell the difference between 720 and 1080.

 

[Deuce]

Another thing to consider is the size of your screen. For example, on a 32 inch television it is impossible to tell the difference between 720p, 1080i, and 1080p unless you're ~4.5 feet or closer to your screen.

I can tell the difference between 720p and 1080i on my 32" LCD easily. Might just be how my TV handles it, but it's pretty obvious, to me.

 

[norton9478]

IF your tv only supports 700 lines or so, you are probably better off running at 720p.

All that aside, things with lots of action often look beter in 720P.

Things with less action or camera movement (such as a documentary) look better in 1080I.

 

[Metal Slugnuts]

Fun Fact: Enter the Matrix for the original Xbox supports 1080i.

 

[brentsg]

If your TV properly deinterlaces 1080i content and you are handing the display a digital signal then it should look brilliant and that should be preferred.

Of course that is a big if. Some displays simply discard half of the 1080i signal to simplify deinterlacing. If you see a HUGE difference between 720p and 1080i on fixed-pixel panel.. feeding it with HDMI, and 720p looks better.. then that is what is happening to your source.

 

[not sonic]

depends on your display.

1080i on a 1080i crt looks great.

its a different kind of picture vs say 720p or 1080p on an lcd.

its tons better than sd for sure.

1080i isnt going to be around much longer i hope, as almost all new displays have been progressive for the past few years now.

im not looking forward to the day when everyones got a 1080p set and broadcasts are still using old 1080i hardware. deinterlacing is almost always noticeable.

 

[SpamYouToDeath]

If you have a progressive display, use a progressive signal. If you have an interlaced display, use an interlaced signal. What's so hard?

 

[-Hibikster-]

Thanks for your answers guys...it kinda sheds a bit more light onto what I want to do.

depends on your display.

1080i on a 1080i crt looks great.

its a different kind of picture vs say 720p or 1080p on an lcd.

its tons better than sd for sure.

1080i isnt going to be around much longer i hope, as almost all new displays have been progressive for the past few years now.

im not looking forward to the day when everyones got a 1080p set and broadcasts are still using old 1080i hardware. deinterlacing is almost always noticeable.

This is what I was getting at...See my dilemma right now is to either invest in a 34" CRT HDTV that supports 1080i or go for a 32" LCD that does 720p. What I play mostly is older 8/16-bit systems plus some 360 fighters for good measure.

If you have a progressive display, use a progressive signal. If you have an interlaced display, use an interlaced signal. What's so hard?

What signals are interlaced and what ones are progressive?

 

[Neo Ash]

This is what I was getting at...See my dilemma right now is to either invest in a 34" CRT HDTV that supports 1080i or go for a 32" LCD that does 720p. What I play mostly is older 8/16-bit systems plus some 360 fighters for good measure.

CRT

 

[SpamYouToDeath]

What signals are interlaced and what ones are progressive?

I'll assume you know 720p, 1080i, etc.
PCs and game consoles output either. Most TV is 1080i, though sports (with a lot of side-to-side panning that doesn't look good when sent interlaced and then displayed on a progressive screen) are often in 720p. Broadcast standards handle either one just fine. Blu-Ray movies are 1080p, but are often in 24hz so it really doesn't matter (24hz p->60hz i is minutely better than 24hz p->60hz p, but don't worry about it).

 

[Deuce]

Blu-Ray movies are 1080p, but are often in 24hz

29.97, typically.

 

[brentsg]

One thing that hasn't been mentioned is that many "720p" displays are actually 768P when you look at the pixel count. If that is the case then you would want to always send the display the exact native signal when possible and let the TV sort it out. Again, this is assuming you are digital and the TV handles the signal.

It is possible to perfectly reconstruct 1080p from a 1080i signal in a digital domain.

So if your display is 768p and deinterlaces well:
-for 1080p source, send it 1080p
-for 1080i source, send 1080i
-for 720p source, send 720p

Otherwise, for 1080p/i sources you would be discarding source resolution.. and then asking the TV to scale 720p up to 768p.... so it's "creating" detail you tossed via interpolation or whatever.

 

[SpamYouToDeath]

29.97, typically.

Well then it really doesn't matter if it's interlaced or not. I sort of assumed it was known that for 30hz material it makes no difference. Just thought it was worth mentioning that it's allowable for them to transfer films over at film framerate.

 

[brentsg]

29.97, typically.

Blu-ray movies are rarely ever encoded like that. Video yes, film.. no.

Example: i, Robot

MPEG-4 AVC Video 1080p / 23.976 fps / 16:9 / High Profile 4.1

 

[SSS]

depends on your display.

1080i on a 1080i crt looks great.

its a different kind of picture vs say 720p or 1080p on an lcd.

its tons better than sd for sure.

1080i isnt going to be around much longer i hope, as almost all new displays have been progressive for the past few years now.

im not looking forward to the day when everyones got a 1080p set and broadcasts are still using old 1080i hardware. deinterlacing is almost always noticeable.

my understanding was 1080P is too high bandwidth for over air transmission. my local fox station runs in 720P vs 1080i.

for regular programming that is. I believe they can do 1080P 24hz (movies) no problem.

 

[famicommander]

Thanks for your answers guys...it kinda sheds a bit more light onto what I want to do.

This is what I was getting at...See my dilemma right now is to either invest in a 34" CRT HDTV that supports 1080i or go for a 32" LCD that does 720p. What I play mostly is older 8/16-bit systems plus some 360 fighters for good measure.

CRT will always, always, always look better for old school games.

Always.