1080 720 visual reference

[poppj]

Hello all. This is my first post. Ive done some research on the differences between 720i/p and 1080i/p. I want to make a good visual reference because there are so many people that want to know the difference and it can be hard to explain.

Ive created the following attachment and I wanted to know opinions and to see if ive done this right. I created it in photoshop... the 1080 lines are created using 2 pixels and the 720 lines are created using 3 pixels (so 720 pixels are 1.5 times the size of 1080). This illustration would be visual during movement onscreen because as i understand, there is no difference between interlaced vs progressive on a still image.

I was hoping to use this to help explain it to a buddy of mine and some people online that constantly ask on PS3 boards.

Let me know what you think.
Jeremy

[poppj]

Oops, this was probably supposed to be in Home Theater. My apologies.

[The Don]

well...1080p is the cream of the crop right now...

720p favors fast action sequences like sports ....1080i favors drama type movies where there is not much movement....

in comparison...1080i and 720p own their territories between eachother and one dooes not do everything better than the other...

1080p is the dominant veiwing perspective for now...

[poppj]

Thanks for the reply, but that doesnt really answer my question. I pretty confident that i understand the technical differences.

I just want to know if i translated that correctly onto the picture in my first post. Specificly the interlaced parts. Any thoughts?

[takezo]

Huh there is no such thing as 720i.

For Blu-ray movies, I say 1080i is best. Downscaling on the fly produces losses in sharpnes, which make for a softer video. 1080i is still 1080 vertical lines, just displayed half of them at a single time. Because the video is not monkeyed with the PQ is sharper and crisper.

For games, right now the texturemaps are not high res enough to tell difference. When super high res texure games come out, not only will they utilize the space of BD-ROM, they will definately make use of 1080p resolution. These games will look better at 1080i, rather than 720p. Much like Blu-ray movies.

As for HDTV, there is no diffrence from 720p and 1080i. Why? Because Bitrate is too low for either to be at 100% quality. Some stations like 1080i, other like 720p. It reall don't matter since they definately look a lot better than Standard Def.

[Aaron]

A still 1080i or 1080p image looks the exact same. It's the same number of pixels. A 1080(i,p) image is around 2 megapixels. And i've never heard of 720i.

[Aaron]

This one may be a little more helpful:

[aaronwt]

Originally Posted by poppj

Hello all. This is my first post. Ive done some research on the differences between 720i/p and 1080i/p. I want to make a good visual reference because there are so many people that want to know the difference and it can be hard to explain.

Ive created the following attachment and I wanted to know opinions and to see if ive done this right. I created it in photoshop... the 1080 lines are created using 2 pixels and the 720 lines are created using 3 pixels (so 720 pixels are 1.5 times the size of 1080). This illustration would be visual during movement onscreen because as i understand, there is no difference between interlaced vs progressive on a still image.

I was hoping to use this to help explain it to a buddy of mine and some people online that constantly ask on PS3 boards.

Let me know what you think.
Jeremy

1080i deinterlaced properly to 1080P looks the same as the 1080P diagonal line

[poppj]

The 720i part is just theoretically speaking. I dont know of any 720i tvs or sources... its just theoretical.

aaronwt, thanks for that info. That does help me realize it may not be as simple as my illustration.

[Deciazulado]

Originally Posted by poppj

The 720i part is just theoretically speaking. I dont know of any 720i tvs or sources... its just theoretical.

aaronwt, thanks for that info. That does help me realize it may not be as simple as my illustration.

Your interlaced examples would be correct on showing on how 60i interlaced movement would look on a progressive display that just weaved (not deinterlaced) the two interlaced fields into a frame (what people describe as "combing")

To aproximate the interlaced look on a true interlaced display the serrated edges should look fainter because they would only be perceived for 1/60th of a second (you could make the serrated edges pixels be like medium grey to aproximate that) while the solid (non moving) parts made up of 2 or more scanning lines would still be solid black.

On a progressive set that uses the simple bob method (line doubling) of deinterlacing, the 1080i diagonal line would be made up of a "stairstep" (in your example) 4 pixels tall instead of 2. Vertical running lines on the other hand would still look as fine as the 1080p as they would not be affected by the line doubling.

To aproximate the look of a progressive set that uses slightly better deinterlacing methods you probably have to do a more complicated graphic, maybe halving the height of the serrated 1080i example (but not the width) to 1 pixel tall or creating a graphic with the 1080 pixels represended by 1 pixel tall 2 pixel wide (that would make the diagonal lines' slopes be half, 22.5 degrees instead of 45 degrees) instead of 2 x 2 as in your example and then you would upscale 2x the height only, using Photoshop's bilinear or bicubic interpolations. That'll give you back a slightly fuzzy 45 degree 1080i diagonal.

The most advanced deinterlacers aim to make the 1080i line look as close as the 1080p as possible.