Message-Id: <mailto:199607072037.PAA10572@library.wustl.edu> Date: Sun, 7 Jul 1996 13:33:09 -0700 From: Paula Berinstein <mailto:paulab@NETCOM.COM> Subject: Lossy compression files larger? To: Multiple recipients of list IMAGELIB
A couple of months ago I asked if anyone knew why image files compressed repeatedly with lossy compression methods will eventually get larger rather than smaller. I think I may have found the answer, which I'd like to share.In their write-up of the PCX format in *Encyclopedia of Graphics File Formats, Second Edition,* James D. Murray and William vanRyper state, "It is possible for an image to be so complex that the PCX compression scheme actually causes the data to increase in size after compression." (page 663)
I suspect that this is what I had heard about JPEG as well, though I still remember something about repeated compressions.
Paula Berinstein Berinstein Research Woodland Hills, California (818) 704-6460 (818) 704-1590 fax