Gif animation quality

[VonDuck]

Hi

I have been making a gif animation in Adobe ImageReady.. The problem is, that the quality makes the gif dotted. I can't adjust anything that corrects it. I used a jpg picture for background on the animation, and made it black and white with a blue tone to it. Could it be to much for the gif to handle?? Is has 19 pictures in all.. But should that be any reason for the Gif to become dotted in quality??

[tech_support]

Use Flash.
GIF loses quality especially when it's big.

[djr33]

GIFs can be set on a scale of quality, for lower filesize, if desired.
First step is to be sure it's at maximum quality (if you can afford the filesize).

However, GIFs limit it to 256 colors, total, so you may just need to use a different format (too bad, since JPEGs aren't animated and animated PNGs aren't supported yet) or make your image simpler, or just live with the dotted look.

Using a custom color pallette might help too, but this is done by default in most cases.

[Twey]

Use Flash.

Using Flash won't help at all, unless you redraw the entire image using vectors. If you simply import the image, or any part of the image, it'll just be an embedded GIF. There's also all the accessibility problems using Flash bring up.

GIF loses quality especially when it's big.

No it doesn't. GIF's only limit on quality is its 256 colour limit. Size doesn't matter.

GIFs can be set on a scale of quality, for lower filesize, if desired.

No they don't. GIF is a lossless compression format. You're thinking of JPEG.

However, GIFs limit it to 256 colors, total, so you may just need to use a different format (too bad, since JPEGs don't animated and animated PNGs aren't supported yet) or make your image simpler, or just live with the dotted look.

They are supported in Firefox. If you really can't bear the loss of quality that GIF is causing, I would recommend perhaps using Javascript to animate a series of JPEGs. You could have the original "dotty" GIF as a fallback for non-Javascript browsers.

[djr33]

For flash, that would work, assuming you bring in the original. But it would require flash support which is something you should avoid if possible.

No it doesn't. GIF's only limit on quality is its 256 colour limit. Size doesn't matter.

Optimization engines have several options, such as how many colors (a 2 color gif is significantly less than 256 to store), the way that nonmatching colors are handled (best-guess or dithering), as well as other little things, like optimizing repeated frames, etc.
The word 'big', though somewhat ambiguous, is true in two ways-- 1. a 'big' animation (many frames) would tend to have many colors, and with each frame, it's more likely that there would be more than 256 colors total. With a 'big' image, the same is true, in that there are more pixels to take up colors, so that would run out of the 256 quickly, too.

No they don't. GIF is a lossless compression format. You're thinking of JPEG.

The methods that jpg and gif use to compress differ greatly. JPG tries to hide it from the eye, whereas gif makes it pretty obvious. A gif CAN be more compressed/optimized in that it has fewer colors or less detail (dithering is a main factor there).
While a GIF 'loses' nothing if you save it over and over again*, it still is much lower quality than an original if that original had more than 256 colors or the palette amount of the particular image.
Take a photo. Save as gif. Save as low quality jpg. Which 'lost' more?
(*This is generally the case, but I have on several occasions had weird issues with saving it again, after adding a new color and throwing off the palette, then making many of the other colors change to fit into the new set, so dithering was used and it was all blocky.)

I would recommend perhaps using Javascript to animate a series of JPEGs.

Yeah, but only for a slow animation. Anything more than 3 frames per second or slow would likely stutter on a slower system.

They are supported in Firefox.

And so is xhtml....

[Twey]

A gif CAN be more compressed/optimized in that it has fewer colors or less detail (dithering is a main factor there).

True. That's not compression, though, per se.

Yeah, but only for a slow animation. Anything more than 3 frames per second or slow would likely stutter on a slower system.

Hm, I don't know... I've managed to have Javascript run much more complex operations nicely at 33 frames per second, and my system's moderate but not exceedingly powerful. I should think almost all systems should be able to handle 10FPS quite comfortably.

And so is xhtml....

Aye, I wasn't saying they should be used, it was just that the way you said it made it sound as if nothing supported them.

[jscheuer1]

Quality, compression, and lossless are each both technical and generic terms. Twey is correct when he uses them in their technical sense in this context. However, .gif can be compressed, has quality issues and is not lossless if one is using these terms as generic descriptive words. From that standpoint, its quality is a function of the items djr33 mentioned, perhaps others. It can be generically 'compressed' (made to be a smaller byte size) and, is in fact a compressed format. Anyone who views a complex photograph rendered as a .gif would not think nothing was lost, therefore it is not generically 'lossless', though that technically describes the format accurately.

[djr33]

lossless only applies to the gif format in terms of generation loss.
Save a jpg at the same quality twice, and it will have more compression artifacts.
Save a gif twice (without changng the colors used) and it will be identical.... losing nothing.

Lossless does not mean that it won't lose anything from the original format.

[jscheuer1]

lossless only applies to the gif format in terms of generation loss.
Save a jpg at the same quality twice, and it will have more compression artifacts.
Save a gif twice (without changng the colors used) and it will be identical.... losing nothing.

Lossless does not mean that it won't lose anything from the original format.

It also means that it has no artifacts. With .gif compression, all pixels are rendered faithfully within the limits of the given palette. Whereas, with .jpg type compression, artifacts emerge (when done 'right' these are unnoticeable to the casual eye), as that format only strives to make an adequate approximation of the image. That is why .jpg is just about the best compression method (as far as byte size) for web presentation of intricate images.

[djr33]

Well, I'm not sure if lossless specifically means it has no artifacts, but that has no LOSS. This loss is generation loss.
This works because it has no artifacts, and resaving a jpg causes artifacts to be rendered differently, creating the loss.
The artifacts are related, but not specifically part of it being lossless, except that not having artifacts allows it to be so.
But it's part of the reason it's lossless, not something done as a result of being lossless.