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[Arx]

I'd go so far as to say they don't look like compression artefacts, they are compression artefacts.

I wouldn't notice if you didn't tell me and I didn't have both to compare, but a lot of places that are supposed to have delicate transitions show the compression. Edges of the magenta and some of the green petals are where it seems to show up most.

I'm kind of a colour nut though so...

[scriver]

Oh and to be clear I can't tell any difference either, beside the joke

edit: except when I zoom in. Is zoominning cheating?

[Naturegirl1999]

Oh and to be clear I can't tell any difference either, beside the joke

edit: except when I zoom in. Is zoominning cheating?

I zoom in and still can’t find a difference

[methylatedspirit]

I'd go so far as to say they don't look like compression artefacts, they are compression artefacts.

I wouldn't notice if you didn't tell me and I didn't have both to compare, but a lot of places that are supposed to have delicate transitions show the compression. Edges of the magenta and some of the green petals are where it seems to show up most.

I'm kind of a colour nut though so...

Fun fact: JPEG (and most other lossy image formats) supports YUV 4:2:0 chroma subsampling! You're on the money. The loss in color resolution is more-or-less what you observe in such compressed images.

[methylatedspirit]

edit: except when I zoom in. Is zoominning cheating?

I only stated splitting them up into individual YUV planes as against the rules, so I think it's fair enough.

[Naturegirl1999]

What is image compressing? Is that making an image smaller then making it back to the size it was before?

[methylatedspirit]

What is image compressing? Is that making an image smaller then making it back to the size it was before?

That's lossless image compression. You take an image, and you basically run ZIP compression (but more specialized towards images, obviously) on them so that you can compress and decompress the image without any loss in quality. While larger than lossy, it encodes images at the original quality. PNG, for instance, is lossless.

Lossy image compression is about taking an image and basically considering what details you can throw away so that it's (hopefully) imperceptible to the human eye. This allows you to decrease the file size of an image further than if you went lossless. However, in the process of doing this, you will introduce a degradation in quality. If you iterate it too many times, that's how you end up with those "deep fried" memes or XKCD 1683, a process known as digital generation loss. JPEG is like this.

Some newer formats are able to be both lossy and lossless depending on what settings it was encoded with. WebP and AVIF do this.

[scriver]

Oh and to be clear I can't tell any difference either, beside the joke

edit: except when I zoom in. Is zoominning cheating?

I zoom in and still can’t find a difference

To be precise, what I did was open them both in new tabs, zoom in 300%, then switch between the tabs. After that I can notice the difference between the two when zoomed in here on bay12 too but it wasn't big enough a difference to be noticeable zoomed in side-by-side before, I needed that "flip between what's changed" effect from switching between the tabs to notice it.

[Magistrum]

Took me a minute. Blue inner leafs of the right flower got messed up, but other than that I can't see much wrong here without having zoomed or anything else. Very nice for compression indeed.

[Great Order]

How do you stop your eyes from reactively forcing themselves shut when you're tying to put in contacts?

I'd like to be able to get some, but the consultation went down the drain because even while holding them open with my fingers my eyes would do absolutely everything in their power to close, which made inserting contacts impossible. The best advice Google's given me was literally "Put them in" which is completely fucking useless.

It's not that I can't touch my eye, I can, I can hold my eye open and poke myself in the eye gently, there just seems to be something about putting an actual object in that buggers me over.

[dragdeler]

Train by keeping your eyes open while  you throw water at your face maybe? Idk I don't have glasses but I often catch littlebits and specs with my eyes and I'm getting better at touching the white eventhough I hate it

[McTraveller]

Eventually you can defeat the blink reflex, you can train yourself to stop any flinch reflex after a while.  It does take a while though.

I usually roll my eyes up, and hold my lower eyelid down with a finger, to put in contacts.

[wierd]

This is a question that I realized could be posed to y'all when I posted a visualization of YUV 4:2:0 chroma subsampling on a Discord server. They did not like the fact that they couldn't tell the difference between a full-resolution image and a 4:2:0 subsampled image.

So, Bay12, can you tell the difference between these two images without splitting them into their Y, U, and V components? One is the original, the other is the YUV 4:2:0 subsampled version.

Spoiler: Proof that I'm not messing with you (click to show/hide)

To prove that these are not identical images, I ran the following commands:

Code: [Select]

[REDACTED]@LAPTOP-4K83GCUT:/mnt/c/Users/[REDACTED]/Downloads$ ffmpeg -hide_banner -loglevel error -i 1.png -f rawvideo -pix_fmt rgb24 - | sha256sum | cat
2612fb725c1cc1bc1e151591ee63af73a911e12dca700ea0efb19d4f3d169cd7  -

[REDACTED]@LAPTOP-4K83GCUT:/mnt/c/Users/[REDACTED]/Downloads$ ffmpeg -hide_banner -loglevel error -i A.png -f rawvideo -pix_fmt rgb24 - | sha256sum | cat
88e9721a7067530b6300f3d0d6959460c83cad64f1a309d8f8ba3fe3ef408b8b  -


Nope. They both look the same to me, though I have bad eyesight and can on.y see from one eye, so I’m an outlier

To me, the one on the right has a slightly more vivid cyan component, along with a slightly subdued magenta component, compared to the one on the left.
I would guess that the one on the right is the subsampled one.

[methylatedspirit]

Is there a specific term for phrases like "have fun!" or "good luck!", where it's used to say goodbye to someone leaving for an activity? It's at least a parting phrase, but I need to know if there's a specific subcategory for it.

[Ziusudra]

I think "parting words" is closest. In some contexts "a farewell" or "a goodbye" could be used to refer to such phrases, but that's not very colloquially unambiguous.

Edit: Technically that is what "valediction" means but I've not heard that used that way.