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View Full Version : Whats the diff between 1080i and 1080p besides the p?




G5Unit
Nov 26, 2005, 02:19 PM
I know the i stands for interlaced, but what does that really meen? Are there any screenshots that compare the 2?(On the xbox 360)



risc
Nov 26, 2005, 02:25 PM
You do know the 360 can't do 1080p?

Check out http://www.gamespot.com/features/6140186/index.html and http://www.gamespot.com/features/6139690/index.html for some info about HD on the 360.

G5Unit
Nov 26, 2005, 02:26 PM
You do know the 360 can't do 1080p?

Oh sry duh. I forgot. But will thr ps3 really have any advantage over the xbox because it can do progressive?

GFLPraxis
Nov 26, 2005, 02:27 PM
Here you go:
http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html


Great article, visual comparisons in slow motion, etc.
Interlaced:
http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-tomato-feathering.gif
http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-ski-twitter.gif



Interlaced vs Progressive:

Interlaced: http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-tfe-interlaced.gifhttp://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-casablanca-interlaced.gif
Progressive: http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-tfe-progressive.gifhttp://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-topgun-progressive.gif

G5Unit
Nov 26, 2005, 02:29 PM
Here you go:
http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html


Great article, visual comparisons in slow motion, etc.
Interlaced:
http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-tomato-feathering.gif
http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-ski-twitter.gif



Interlaced vs Progressive:

Interlaced: http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-tfe-interlaced.gifhttp://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-casablanca-interlaced.gif
Progressive: http://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-tfe-progressive.gifhttp://www.hometheaterhifi.com/volume_7_4/images/dvd-benchmark-part-5-topgun-progressive.gif


Uhh!Interlaced looks terrible! Why wouldn't the 360 support progressive?

risc
Nov 26, 2005, 02:31 PM
Oh sry duh. I forgot. But will thr ps3 really have any advantage over the xbox because it can do progressive?

The xbox does 720p and the fact that the PS3 is capable of doing 1080p doesn't mean developers will use the format, if you remember back to the PS3 "demos" (and I use the word lightly) the stuff shown using the new Unreal engine was all at 720p.

G5Unit
Nov 26, 2005, 02:32 PM
The xbox does 720p and the fact that the PS3 is capable of doing 1080p doesn't mean developers will use the format, if you remember back to the PS3 "demos" (and I use the word lightly) the stuff shown using the new Unreal engine was all at 720p.

So even if I have a TV capable or 1080i, can I still play a slightly blurry 720p?

GFLPraxis
Nov 26, 2005, 02:33 PM
A great article on the subject:
http://www.projectorcentral.com/video_signals.htm

Some quotes:
So let's forget about HDTV for a moment. The big leap forward that is accessible to everyone right now is EDTV, which is simply progressive scanning. I had friends over recently and I put on the Eagles "Hell Freezes Over" DVD, displaying it on a 120" diagonal screen. They were stunned at the picture quality—"I've never seen ANY big screen ever look that good," said one. "So that's HDTV huh?" Nope. That's just regular DVD my friends, played on a progressive scan DVD player.

EDTV is 480p.


http://en.wikipedia.org/wiki/Progressive_scan

Advantages of progressive scan include:

* Subjectively increased vertical resolution. The perceived vertical resolution of an interlaced image is usually equivalent to multiplying the active lines by about 0.6. This explains, for example, why HDTV standards such as 1080i (1920x1080, interlaced) in most cases deliver a poorer subjective quality than 720p (1280x720, progressive).
* No flickering of narrow horizontal patterns
* Simpler video processing equipment
* Easier compression

risc
Nov 26, 2005, 02:34 PM
So even if I have a TV capable or 1080i, can I still play a slightly blurry 720p?

You really have no idea about HD do you? 1080i would be blurry not 720p, 720p is progressive scan 1080i is interlaced.

Here is a picture of the 360 running 720p

http://img288.imageshack.us/img288/7940/720p1mk.jpg

and here is it is in SD still progressive scan

http://img288.imageshack.us/img288/2551/480p5wq.jpg

Obvisouly both will look better than this because this was taken straight off a tv. In real life I'm sure 720p just looks amazing.

Flying Llama
Nov 26, 2005, 02:37 PM
I think he meant blurry because of the lower resolution.

GFLPraxis
Nov 26, 2005, 02:37 PM
Uhh!Interlaced looks terrible! Why wouldn't the 360 support progressive?

Well, interlaced is what you see on a normal TV, 480i, it just goes really fast (sixty fields per second, those images shown are slow motion and show about six fields).

The 360 supports 720p, which is lower resolution but a higher framerate (60 frames per second instead of 60 fields (half frames) per second), brighter, looks better in motion and removes the jaggies caused by interlacing, so many feel 720p looks better than 1080i.


The PS3 supports 1080p, 1080i, 720p, 480p, and 480i (SD).
The 360 supports 1080i, 720p, 480p, and 480i (SD).



So even if I have a TV capable or 1080i, can I still play a slightly blurry 720p?

No; some HDTV's support both 1080i and 720p, and others support only 1080i. Check which your TV does.

However, all HDTV's will support 480p. So I'd say test. Compare 480p and 1080i and check if you have 720p. See which looks better; higher framerate and brighter image/contrast or higher resolution.

risc
Nov 26, 2005, 02:41 PM
I think he meant blurry because of the lower resolution.

A TV that can do 1080i and 720p but not 1080p is going to have a native resolution of 720p, imo that makes 720p the better choice.

GFLPraxis
Nov 26, 2005, 02:43 PM
Well when you think about it, even though 720p is a lower resolution, because it does a full frame instead of fields you are seeing more pixels per second.

gnasher729
Nov 26, 2005, 03:36 PM
Uhh!Interlaced looks terrible! Why wouldn't the 360 support progressive?

In the real world, interlaced doesn't look that terrible at all. In the examples that you saw, it looked like the screen was erased first, then the first half of scanlines filled in, then the next half. In reality, one half of scanlines overwrites the screen, then the other half overwrites the other half. There are two passes, but each pass is twice as fast as with progressive.

When progressive is exactly half done with a frame, the top half is from the new frame, the bottom half still from the old frame. With interlaced, every even line is from the new frame, every odd line from the old frame.

clayj
Nov 26, 2005, 03:46 PM
Short answer: 1080p will look marginally smoother (less jumpy) than 1080i because there will be no interlacing.

Long answer: Of course, the reality is that pretty much all plasma TVs, and most LCD TVs, don't even have 1080 lines of resolution in the first place: most of them have 768 lines of resolution, so a 1080 signal is getting downconverted to 720 anyway. This is why ABC and FOX, for example, broadcast their HD content in 720p instead of 1080i... the 1080i usually gets dropped to 720i (effectively) when TVs can't show all 1080 lines. If you can't show all 1080 lines, the best thing to do is to show what you can (720 lines) in the best format (progressive). So, 720p is often BETTER than 1080i (and just as good as 1080p, when it comes along).

Only when TVs have 1080 lines will the 1080p really be any better than 720p.