Re: Raw picture reduction

Woody <usenet@xxxxxxxxxxxxxx> wrote:

Rowland McDonnell <real-address-in-sig@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
Woody <usenet@xxxxxxxxxxxxxx> wrote:
[snip]

('ere, Woody, whatever your news client is, it's buggering up quoting
when it line wraps)

I've got graphics files in the hundreds of megabytes. I'm not running
a big printing press either. We both have gigabytes of RAM and (okay,
not many) terabytes of disc space. 25MB is peanuts.

Again, not in this context. I had 3gb left on a 320gb disk.

Again, in this context, you can get nearly 10,000 images of that size on
a disc like that.

<shrug>

The whole issue was that these images (at 8MB) were way larger than
needed

Fair enough - but 25MB is `not a lot' when stuck on a 320GB HDD. So
you've got a lot of data and are looking for savings - fine. But 25MB
is still not a lot, for all that it'd useful to squeeze down `a big pile
of high quality images if you really need to save space'.

I've got a 20MB HDD. Yes, *mega*bytes - hooked up to my Mac Plus (well,
not actually plugged in at the moment - stuck at the bottom of the spare
room wardrobe as it happens).

[snip]
Umm. If you can see differences, then you are seeing compression
defects.

Ok, well in that case both jpeg and jpeg2000 are defective by design,
as they appear immediately.

Not at all - the *point* is to introduce defects, so as to save on
space. The other point is that the defects introduced by JPEG2000 are
less nasty than those introduced by original JPEG.

But failed to replicate that in my tests

I'd like to see what you saw - my tests, and bear in mind that I did
*NOT* expect to see any improvement from JPEG2000 /at all/ - my tests
showed a huge improvement.

Come on, you saw the benefits of JPEG2000 in the example I sent, didn't
you?

[snip]

jpeg 2000 certainly produces a less troubling degredation at higher
compression ratios (on smaller pics, these are all 3500 x 2900) where
the jpeg comes up with the cell patterning, allthough at full
compression, where the jpeg is badly squarey, the jpeg2000 has a huge
line through it

Huh? What what what? Go on, email me with this one, I'd like to
see it.

Ok. I think it is something to do with block size, as there was a
control for that

I've not seen any email from you. Did you send me anything?

JPEG2000 doesn't use blocks. It works on wavelets, which is `doing
the job properly'.

Well, there was a control that mentioned the word block and was set to
1024

Ah. Word blocks - dunno about that, sounds to me like something in the
stored data structures unrelated to the image side of things, IYSWIM.

Image blocks is what you have in JPEG, and - ooh, therein lieth the
fault. JPEG2000 works on wavelets as the `basic unit to compress'.
Wavelets are `what the image is made out of'. It's why JPEG2000 is
guaranteed to work better - as I found out after I'd seen that it *IS*
better.

[snip]

Cocoa used to be a full-on programming environment long before MacOS
X. It was a graphical programming language for young childen - from
Apple, no less. Can I find one single reference to it on the Web these
days? Nope.

I have never heard of that before. Cocoa became cocoa after the
developer release of rhapsody, what was to become osx.

There you go then.

You are not confusing this with smalltalk were you?

<cough> Is Smalltalk a graphical programming language that lets kids
build - oh, I've sent you the manual, check your in-box.

Cocoa was a 1990s Apple thing - purely graphical. Smalltalk was a
1970s-originating thing, purely textual, and not for children.

Objective c which is
the language that is generally used to create cocoa interfaces has a
history that draws some techniques from smalltalk, although is very
dissimilar in other ways

Check your in-box.

Smalltalk was made for children to be able to control computers
originally,

Not from what I've just read about it. The examples I've seen show it's
not at all suitable for young children at least - you'd want high school
kids who are keen on computers and good with words, not `any old
youngster'

and is a nice language for teaching.

So it is said - but you know what? The examples I've just looked at
make it look like a complete nightmare to use for anyone.

Modula-2 is a nice language for teaching. I did once start to learn
Pascal and that didn't bother me, so I assume even I'd get on with
Modula-2.

I do believe that you
would gain more from teaching a child smalltalk than office but the
crapness of computer science education (rather than IT) is another
matter

You'd gain more from teaching them anything other than MS Office.
Cookery would be a good start. I saw two late teens girls in Tesco one
time, looked like they'd just left school and got a flat together as
mates so they could afford to live away from parents. They didn't have
a lot of money (I was eavesdropping shamelessly) but ended up buying
tinned pasta because they couldn't work out how to cook the dried stuff.

These days, I'd tell 'em, and give 'em a few tips on economical living
for the young (having been a student myself, I have more than a few such
tips) - but that was about ten years ago, and back then I was
uncomfortable about striking up a conversation with a couple of random
just-out-of-school-girls. Not that it's the sort of thing I do these
days generally, but I'm less bothered about talking to people.

There is little-or-no computer science education in UK schools that I
know of.

Rowland.

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