Zipping

[tell-me-more]

Can I zip mpegs and jpegs to make smaller files so I can back up more easily?

What would I need to download? Old PC, windows me.

[rojash]

jpegs and mpegs are already compressed. In some instances, attempting to zip them will result in a file that's larger than the original.
You can reduce the size of a jpeg by opening it in an image editor and reducing the resolution (making the picture smaller) or increasing the compression (lowering the quality).

[VHG]

mpegs and jpegs are already in a compressed format so zipping them would probably gain only about 1 or 2 % of the total file size.

[ACtheTROLL]

not strictly true mon braves

have a look at
http://www.elektronik.htw-aalen.de/packjpg/

http://my.smithmicro.com/mac/stuffit/index.htm l

only done a quick try but these two do seem to work!! lossiless compression of media files ... see what you think

[VHG]

My guess (no scientific evidence to back it up) that anything that compresses an mpeg or jpeg file can only do it by losing some quality.

As most compression formats already lose quality by their very nature (like mp3) then I dont see any way of compressing these files without more quality loss.

But then what do I know.

[ACtheTROLL]

VHG
using the normal tools - I agree
however there are a number of speciallist compressors which only do a single job (most are also v expensive)
fer instance
take an address

some pretentious house name
123 some quite posh street
a nice quiet area
small rural village
west yorkshire
england
aa1 3bb
united kingdom
earth
solar system

using the "postcode compressor" it can be compressed to 123aa13bb
trying to use the same method on a text file won't work ..(apples and oranges)

zipping (not a reference to the american method - however actually that IS where the name comes from!)
the same info CAN be compressed (ie removing all the spaces) to an extent ... not as efficiently - but it works on all file types

zip is a good general purpose compressor (allegedly)
it's efficient with text files, fair with exe and cr@p with jpg

at work I use
PEcompact
Uharc
upx
plus other packages ...
and its possible to get 60% or more in some cases
but it's tedious ... and the installer needs 1000s of lines

oh and also zip - because just about everybody can use zips

installers tend to use a mix of methods - so a 650Mb CD needs 2Gb + of HDD space - the tradeoff is ... it takes ages to install.