Compression

David Rees drees "at" oto.dyn.ml.org
Fri, 27 Feb 1998 09:04:04 +0000


Compression is a good idea, but how long did it take to gzip that 5.5MB
file?  Server performance is going to suffer.  Just a thought...

-Dave

On Fri, 27 Feb 1998, Robert Schmidt wrote:

> I suggest going one better, using some proper compression technique,
> like gzip or PNG, instead of proprietary techniques like that.  VNC was
> virtually useless over a modem, as dithered parts of the screen came
> across one pixel at a time.
> 
> I dumped a 1600x1200 24-bit uncompressed BMP of my typical desktop
> (mostly windows with text and some icons).  The BMP was 5.5 MB.  Next, I
> zipped it with maximum compression, and the resulting ZIP file was 82
> KB.  And that's *24-bit*.
> 
> Dr. Joel M. Hoffman wrote:
> > 
> > Having looked a bit further at vnc over the Internet and a slow modem,
> > first I want to publicly state that I'm very impressed.  VNC makes
> > very good use of bandwidth.  I have a suggestion for improvement.
> > 
> > Many screen backgrounds consist of repeated patterns, and while VNC is
> > great at sending solid backgrounds in a jiffy, the patterned
> > backgrounds take longer.  In general it's pretty hard to figure out
> > what repeats in the background, and then code it properly so as to
> > make it as efficient as solid colors, but I wonder if cheating a bit
> > wouldn't help.  Why not look at the current background pattern as
> > listed in the registry, and then send that as repeated?
> > 
> > (Screen savers are the other big waste of bandwidth....)
> > 
> > -Joel
> > (joel "at" exc.com)
> 
> --
> Robert Schmidt <rsc "at" vingmed.no>
> Software Developer / Vingmed Sound tel +47 67124237 fax +47 67124355
> Private tel +47 22606076 WWW http://www.nvg.unit.no/~rsc
> 
>     jeg lukker et oye og ser halvt
>     jeg  lukker begge  og ser  alt            -- seigmen
> 
>