Path: utzoo!attcan!uunet!sjsca4!greg
From: greg@sj.ate.slb.com (Greg Wageman)
Newsgroups: comp.graphics
Subject: Re: Comp.graphics.images
Message-ID: <1989Nov21.045304.18909@sj.ate.slb.com>
Date: 21 Nov 89 04:53:04 GMT
References: <30763@mips.mips.COM> <4810@rice-chex.ai.mit.edu> <340@vixen.uucp> <7821@bunny.GTE.COM> <2586@canisius.UUCP>
Reply-To: greg@sj.ate.slb.com (Greg Wageman)
Organization: Schlumberger ATE, San Jose, CA
Lines: 33

Opinions expressed are the responsibility of the author.

In article <2586@canisius.UUCP> jarnot@canisius.UUCP (Repo Man) writes:
>In article <7821@bunny.GTE.COM>, sg04@GTE.COM (Steven Gutfreund) writes:
>> What sort of compression will be used for these images? Also are there
>> better publicly available compressions that unix COMPRESS (Lempel-Ziv)?
>
>If the images are GIF pictures, they are already compressed due to the fact
>that they ARE GIF pictures.  The image data is compressed with a Lempel-
>Ziv type compression method.  I'm not sure how much space will be saved
>from running compress on the uuencoded image.

Here are some examples:

Size-----v
        28744 Nov  1 10:56 fall.gif    (Pure GIF)
        39631 Nov 20 17:07 fall.uue    (Uuencoded GIF)
        35921 Nov 20 17:07 fall.uue.Z  (Uuencoded, compressed)

        20776 Oct 10 10:23 vase.gif
        28653 Nov 20 16:59 vase.uue
        26153 Nov 20 17:00 vase.uue.Z

The uuencoded and compressed versions of the GIF images, while smaller
than the uncompressed, uuencoded versions, are still about 25% larger
than the pure GIF data.

These numbers will, of course, vary from image to image.

Copyright 1989 Greg Wageman	DOMAIN: greg@sj.ate.slb.com
Schlumberger Technologies	UUCP:   {uunet,decwrl,amdahl}!sjsca4!greg
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