michthro
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The JPEG format (or I think the format itself is actually called JFIF) is designed to compress photo-realistic images, at which it is amazingly good. It assumes a certain kind of continuity, so it's not ideal for images with sharp borders, such as cartoon style images or a white square inside a black square. (And compressing such images isn't exactly a challenge. A simple run-length encoding scheme or the LZW scheme used in GIFs works very well.) Even so, it's not as if it makes a total mess of it - you have to look carefully to find anything wrong.

trick
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File: BlackNWhite.png (180 bytes)
Downloaded 41 times.
License: Public Domain

I think the point is that jpg is not always the best tool for the job (and it's never lossless, even at 100% quality).

Also, that jpg was 5989 bytes. The png version of the same image, lossless and without artifacts, is 180 bytes.

(FWIW, I encode my oggs at -q 5 ).

Edit: Didn't see michtro's post there, which makes mine rather redundant. Oh well, I'll leave mine up.

- Gerry

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[Last edited by trick at 07-04-2006 10:32 PM]

Banjooie
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Oneiromancer wrote:
...so?

I mean really, is it that big a deal? Maybe I'm not one to talk, since I record my mp3s at 128 kbps, but still...

Game on,

Gah, if you're a pixel artist, yes. JPG is frigging icky whenever you're doing anything pixel artist-like.

eytanz
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Banjooie wrote:

Oneiromancer wrote:
...so?

I mean really, is it that big a deal? Maybe I'm not one to talk, since I record my mp3s at 128 kbps, but still...

Game on,

Gah, if you're a pixel artist, yes. JPG is frigging icky whenever you're doing anything pixel artist-like.

Well, sure. That's because, as pointed out above, JPEG isn't designed to work well for pixel-based art. But that doesn't imply there's anything wrong with JPEG. The main problem is that JPEG is designed as a specialized tool, but, because of a variety of irrelevant reasons in the history of web-based graphics, it has become a de-facto standard for a lot of things that it isn't the correct tool for. But that's not a problem with JPEG, it's a problem with the people who use it improperly. If you met someone who spilt soup all over himself because he insisted on eating it with a fork, it's not the fork you should blame.

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Mattcrampy
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eytanz wrote:
because of a variety of irrelevant reasons in the history of web-based graphics, it has become a de-facto standard for a lot of things that it isn't the correct tool for.

I thought the reason was 'you have to pay for the GIF algorithm'. Well, at the time when the standards were being settled on.

I'm fascinated by the chaotic nature of decisions like this, and this is my way of baiting Eytan to go into as much detail as he knows about.

Without actually asking.

Yeah.

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Pilchard VIII
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Someone was bound to say this eventually...



This started out as a conversation about mismapped stairs, and now it's about JPEGs and PNGs. Well, I'm just gonna say this...


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Syntax
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Guess it's time to post pics of mismapped stairs in your favourite format

Hikari
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File: Picture 3.png (177.4 KB)
Downloaded 45 times.
License: Public Domain

Kinda late to be putting this in, especially after the Off-Topic call and two days of the thread doing nothing, but if Elfstone looks, speaking as a fellow Mac user, a few tips for you to help with what people were saying in this thread...

There's a few keyboard shortcuts for creating screenshots without using Grab, which are as follows:

Command(Apple)-Shift-3 : Full screen, creates a PNG file on your desktop.
Command-Control-Shift-3 : Full screen, saves to clipboard for use in graphics software.
Command-Shift-4 : Gives selection cursor, creates PNG of area you select on the desktop.
Command-Control-Shift-4 : As above, except to clipboard.

Also, you've got the opening of zip files down, and making them isn't *too* much more complicated. You select the files you want to zip in Finder, then you use the 'Archive' option in the File menu to make a zip file. The attached file shows where that is in the list. It won't normally be under the 'Add to Favorites' option as that only comes up when you're holding Shift, but... Well, you hold Shift to do screenshots

^^ Always nice to wander this forum and see all the other Mac users around...

EDIT: Hmm... Looking at the DROD I was running at the time and Beethro's expression and where his eyes are pointed, I guess he doesn't approve of creating ZIP archives.

ALSO EDIT: Whoooooah... Never seen one of my own posts get modded up so fast o_o

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[Last edited by Hikari at 07-07-2006 01:59 PM]

Elfstone
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Hikari wrote:
speaking as a fellow Mac user, a few tips for you to help with what people were saying in this thread...

There's a few keyboard shortcuts for creating screenshots without using Grab, which are as follows:

Command(Apple)-Shift-3 : Full screen, creates a PNG file on your desktop.
Command-Control-Shift-3 : Full screen, saves to clipboard for use in graphics software.
Command-Shift-4 : Gives selection cursor, creates PNG of area you select on the desktop.
Command-Control-Shift-4 : As above, except to clipboard.

Yes I've used these; in fact the pictures I posted in my first three! - sorry!! posts in this thread were taken using the 'GRAB' software, but they created something called 'TIFF' files which as I said above came in at somewhere between 1MB and 1.9MB - too big for attachments I thought.

Also, you've got the opening of zip files down, and making them isn't *too* much more complicated. You select the files you want to zip in Finder, then you use the 'Archive' option in the File menu to make a zip file. The attached file shows where that is in the list. It won't normally be under the 'Add to Favorites' option as that only comes up when you're holding Shift, but... Well, you hold Shift to do screenshots

Thanks, I'll try that if I ever need to post a file here again.

^^ Always nice to wander this forum and see all the other Mac users around...

Indeed! Actually I have just posted a reply to your High Score Counts thread on the assumption that you are a Mac user.

Elfstone.

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Hikari
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Elfstone wrote:
Yes I've used these; in fact the pictures I posted in my first three! - sorry!! posts in this thread were taken using the 'GRAB' software, but they created something called 'TIFF' files which as I said above came in at somewhere between 1MB and 1.9MB - too big for attachments I thought.

Nothing to apologize for... you didn't know about the Archive option; a lot of Mac users don't, either, and I didn't even notice it for almost two months after it first became available. And you did the right thing with those files, too. If I recall correctly, TIFF is an uncompressed format, and isn't workable for online purposes anyways. JPG and PNG may have people arguing over their usefulness online, but they're both infinitely more useful in this setting than TIFF (though any of the above are better than the PDF format screenshots that the shortcut keys *used* to create o_O)

Thanks, I'll try that if I ever need to post a file here again.

Hee... you only need to do that if you're trying to post more than one at once.

Actually I have just posted a reply to your High Score Counts thread on the assumption that you are a Mac user.

Nice to see someone actually making that assumption about me once in a while ^^

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