Animated .GIF super-compression

[JJones]

When I make an animated gif I'm able to open it later and resave it at the same file size. Sometimes I'll find a gif where this does not apply. Two examples:

https://forum.videohelp.com/images/imgfiles/s5ZW5.gif
and
https://forum.videohelp.com/images/imgfiles/mn0lG.gif

With those two, it's impossible to resave them at the same file size using ImageReady, Jasc, or Premiere. The file sizes bloat by 1M.

Any ideas about how these gifs were super-compressed? I thought .gif was a lossless format that allows you to clone an image. If there's a better forum to post this lemme know and I'll move the thread. Thanks!

[guns1inger]

I assume you are making changes to the files, otherwise why open them and re-save them. So what changes are you making ? Gif is only lossless up to a point.

[El Heggunte]

Any ideas about how these gifs were super-compressed? I thought .gif was a lossless format that allows you to clone an image. If there's a better forum to post this lemme know and I'll move the thread. Thanks!

IIRC, at least Microsoft GIF Animator had a "P-frame based" compression mode --- i.e., certain frames were compressed as the "difference" between themselves and the previous frame.

[thecoalman]

IIRC, at least Microsoft GIF Animator had a "P-frame based" compression mode --- i.e., certain frames were compressed as the "difference" between themselves and the previous frame.

Yep, the animation in the second link has a tansparency applied to every frame.

[JJones]

Thanks for the replies. If you check the EXIF info at the bottom of this post, Imageready uses transparency as well, but maybe not as much?

I resaved this image https://forum.videohelp.com/images/imgfiles/s5ZW5.gif with MS GIF animator and the file size is 2.99M. The original gif is 2.68M, so it's still bloating, but not as bad as bloating to 3.9M in Imageready.

Also, if I resave a gif made in Imageready, using MS animator, it is the same size. That is, MS animator does add any more transparency or compression that I'm lookin for.

So, I'm back to the original question, how can I clone this https://forum.videohelp.com/images/imgfiles/s5ZW5.gif
at the exact same file size using video or image editing tools?

EXIF info of the original:
https://forum.videohelp.com/images/imgfiles/yqPQv.jpg

EXIF info of the bloated image after resaving with Imageready:
https://forum.videohelp.com/images/imgfiles/Khqzg.jpg

[El Heggunte]

I resaved this image https://forum.videohelp.com/images/imgfiles/s5ZW5.gif with MS GIF animator and the file size is 2.99M. The original gif is 2.68M, so it's still bloating, but not as bad as bloating to 3.9M in Imageready.

Also, if I resave a gif made in Imageready, using MS animator, it is the same size. That is, MS animator does add any more transparency or compression that I'm lookin for.

Hmmm, that really sounds weird . To the best of my memory, MS GIF Animator allows you to choose from 3 compression-modes for each frame of the sequence.