Blu-ray is 1080p, so why care about 4k scans?

[xxxJohnDrakexxx]

Originally Posted by spectre08

This is the biggest source of why 4K scans look more "film-like" than 2K. Because you're actually capturing the disorderly variations in the film more accurately.

I don't think 4K scans on Blu-ray are more "film-like". In the end, 2,073,600 pixels is 2,073,600 pixels.

[spectre08]

Originally Posted by xxxJohnDrakexxx

I don't think 4K scans on Blu-ray are more "film-like". In the end, 2,073,600 pixels is 2,073,600 pixels.

the entire rest of my post explains why that's not true

[42041]

Originally Posted by xxxJohnDrakexxx

In the end, 2,073,600 pixels is 2,073,600 pixels.

So then, uh, logically an upscaled DVD is the same quality as native HD content.
It certainly matters how you get to the 1080p image. And oversampling is a very good thing for analog-to-digital conversion (and a lot of high-end 2K scans are oversampled, often internally in the scanner) - because aliasing is a very bad thing and optical low-pass filters suck. But the benefits of the finished 4K master resolution for HD consumption, by itself, are overblown.

[xxxJohnDrakexxx]

Originally Posted by spectre08

the entire rest of my post explains why that's not true

Except it is. Most Home TVs/Projectors are 1080p. They literally only have 2,073,600 pixels. No "disorderly variations" can be displayed smaller or greater than a pixel. Whether you scan at 2k or 100k, you will be encoding at 1080p (2,073,600 pixels) and displaying at 1080p (2,073,600 pixels).

[tvine2000]

Originally Posted by xxxJohnDrakexxx

Blu-ray is 1080p. It does not support HDR. Whatever the scan used, it will still be encoded and displayed at 1080p. So if all of this is true, why is there this push for 4k scans on regular Blu-rays?

Mind you, I'm not talking about UHDs. UHDs are 4K and support HDR and wide gamut color. There the source is being encoded and displayed at 4K resolution, but a regular Blu-ray is still just 1080p, no matter how you slice it.

Is there really a difference between a clean 1080p/2k/4k source if the end result is encoded and displayed in 1080p?

I have the samsung uhd pack and the movies i watched in 4K are amazing. There is some debate about ''is it really 4K''since for example The Avengers ,because it wasn't shot in 4K ,but shot in 2K. The thing I noted right off watching the uhd pack was the HDR and wide gamut color. You can see the difference. In the end the resolution is not important (4k native or 2k) What's the deal breaker is the HDR and wide gamut color. 4K will take a couple of years to take off ,but I believe it will do as well as Blu-ray 1080p has done. I think once broadcasters start showing ''sports in 4k '' things will change fast and the price of 4k blu-ray players.

[xxxJohnDrakexxx]

Originally Posted by 42041

So then, uh, logically an upscaled DVD is the same quality as native HD content.

No, because you are taking 345,600 pixels and are extrapolating. 2k is a higher resolution than 1080p. You are not extrapolating. You are losing information. 4k loses information. 100k would lose information. Whatever super duper k you want to scan at will be encoded at 1080p for Blu-ray because that is the standard. 2,073,600 pixels MAX.

[42041]

Originally Posted by xxxJohnDrakexxx

2k is a higher resolution than 1080p. You are not extrapolating. You are losing information. 4k loses information. 100k would lose information. Whatever super duper k you want to scan at will be encoded at 1080p for Blu-ray because that is the standard. 2,073,600 pixels MAX.

Well, it isn't that simple, because aliasing is a thing, and you can deal with it much better if you oversample in the digital domain.

[Bluyoda]

Originally Posted by chip75

You can do it yourself at home, pop something into your scanner and scan it at 150dpi then at 600dpi and scale the 600dpi image down to 150dpi. The results should be in the downscale's favour. Restoration is easier too, as they have more pixels to work with.

Most BD's 1080p video is actually blown-up slightly from the extracted image from a 2K scan. So whilst 2K has a higher resolution than 1080p, the 1080p image is roughly blown-up 10% from the 2048 x 1566 image (depending on the equipment used to shoot the movie or show).

Is that true? Why would they do that?

Originally Posted by c1nn1c

Just like music, the better the source, the better the downconversion. Film preservation also plays a big part in it, especially if restoration work is needed.

That certainly rings true to me.

I am a nature photographer, and there is a big difference between a 1080p image displayed, or a 15 mega pixel image displayed on a 1080p screen.
Detail, color reproduction, noise/grain....

[Dragun]

Originally Posted by 42041

The particulars of how that camera works has nothing to do with the question at hand.
The bottom line here is that I don't think anyone can reliably tell which modern DI-based movies (which is to say assuming a top quality 2K source) come from 2K masters (like the vast majority of big-budget blockbusters) and which come from 4K ones. I'm sure there is a difference, but there are much bigger factors.

Even with a 2K DI, the film elements (if shot on film) are often scanned at 4K, to take advantage of oversampling's benefits, and to allow for reframing and cropping. If shot digitally with a resolution of 4K or higher, that too is oversampling.

It's well known in the film/video industries that you get more detail if you shoot at a higher resolution and downsample, versus shooting at your target resolution. This is partly because every camera has an OLPF filter (optical low-pass filter), which is an anti-aliasing filter. This reduces detail somewhat, so if your camera sensor is 2K, you're not really getting quite the full 2K worth of detail. But if you shoot at 4K, even with the 4K camera's OLPF there's enough detail there that you can downsample to 2K and retain more detail.

Some 1080p cameras these days have 4K sensors, so the oversampling is happening within the camera itself in those cases.

[spectre08]

Originally Posted by Bluyoda

Is that true? Why would they do that?



That certainly rings true to me.

I am a nature photographer, and there is a big difference between a 1080p image displayed, or a 15 mega pixel image displayed on a 1080p screen.
Detail, color reproduction, noise/grain....

exactly. A long long time ago I shot a lot of work with a Nikon D1, which is about a 2K sensor. That was a great camera, but the pictures were not nearly as good as those taken later with the D80 (about 3.8K) I replaced it with, even using the exact same glass and viewing on the exact same screen.

[Blu MacReady]

Originally Posted by Bates_Motel

Same difference when it comes to scanning, as long as the source is good. And in my years as a photographer, cinematographer and editor, it always looks better to shoot large and RAW then downsize.

4K VS HD: Side By Side Comparisons (Part 3) (Using Same Camera) - YouTube

Can I truly see the benefits of this YouTube clip, showing 4K while not watching it on 4K?

Sounds stupid to ask, but isn't this like showing someone HD on an old preHD TV?

[spectre08]

Originally Posted by Blu MacReady

Can I truly see the benefits of this YouTube clip, showing 4K while not watching it on 4K?

Sounds stupid to ask, but isn't this like showing someone HD on an old preHD TV?

that's precisely the point. Even when viewing AT 1080p the difference is noticeable. Overall the image captured at 4K is sharper and cleaner. full stop.

[42041]

Originally Posted by spectre08

Overall the image captured at 4K is sharper and cleaner. full stop.

...on that particular camera.
Another camera might have way better 1080p output, say, due to internal oversampling.
Same goes for 2K scans.

[Ambler1980]

Originally Posted by xxxJohnDrakexxx

Blu-ray is 1080p. It does not support HDR. Whatever the scan used, it will still be encoded and displayed at 1080p. So if all of this is true, why is there this push for 4k scans on regular Blu-rays?

Mind you, I'm not talking about UHDs. UHDs are 4K and support HDR and wide gamut color. There the source is being encoded and displayed at 4K resolution, but a regular Blu-ray is still just 1080p, no matter how you slice it.

Is there really a difference between a clean 1080p/2k/4k source if the end result is encoded and displayed in 1080p?

If 4K scans didn't make a difference, I seriously doubt studios would do them in the first place. I mean, you have some of the best film technicians in the world working for the studios in post production, why would they even bother if it they knew it didn't make any difference?

I think that pretty much answers your question.

[Trax-3]

Originally Posted by 42041

I don't think there's anything you can conclusively determine from just that. Inglourious Basterds was a 2K DI, Django Unchained was a 4K DI, both blu-rays look stellar.

But both were likely scanned at 4k if not higher. Mastering resolution is of little importance.

Higher resolution scans just look better and more refined. Anyone who has spent some time looking at even still photographs knows it. The sharpness of the image and the refinement of the grain structure is something else.

Photographers don't spend good money on drum scans for no reason.

[Trax-3]

Originally Posted by Bluyoda

Is that true? Why would they do that?

Intended presentation area within 2k scan.

[I KEEL YOU]

Well, for one because if it's a 4K scan, then you know it's a modern scan that shouldn't have any problems.

But from my experience, the difference between a 4K scan and a modern/good 2K scan isn't as great as the difference between a good 2K scan and one of those ancient Universal 2K scans.

[Opips3]

Sony explained me. BDs mastered 4K from scanned film 4K while bd player 1080p. It's good pic images.

BDs mastered 4K put on UHD player display 4K while UHDTV. Identified full picture from scanned film 4K. Its excellent pic images. No HDR.

[42041]

Originally Posted by Trax-3

Mastering resolution is of little importance.

Well, that's basically what I'm saying - the resolution of the 2K DI tells you nothing about how the image was harvested and the things that actually matter for bluray.
And likewise, for older films, that something is a 4K transfer doesn't tell you much about the source they used. While it's usually a good assumption that they scanned camera negative, there are some 4K transfers made from downstream elements where the 4K resolution is pretty much wasted.

[hedliniv]

Ghostbusters is a great example. The first blu-ray was a snow storm!

Originally Posted by dallywhitty

Oversampling. A Blu-ray sourced from a 4K scan as opposed to a 2K scan will have a slightly better, more filmic appearance. I think.

Loldunno.

Somebody more knowledgeable will come along and explain it better but I reckon that's the gist of it. There is a benefit to using a 4K scan, just not a major one. There's future-proofing to consider as well, I guess. When a company announces they're performing a 4K restoration, you know it'll still be suitable when the next format comes along.