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24bit Jpeg to 8bit Jpeg (or bmp)

Does anyone know how to convert a 24bit jpeg to 8bit jpeg (or bitmap) with
some sort of palette optimisation and dithering?

Do I have to fork out for a 3rd party tool like pixelGraphics library for
this?

Is it possible to have a bitmap with 512,1024.... colours as 256 is a bit
grainy?

Is all this more difficult that growing hair on a bald man?

Cheers, Damian.

 

Re:24bit Jpeg to 8bit Jpeg (or bmp)


In article <01bd4ce4$749ad300$a35d8...@dialup.mpx.com.au>, "Belinda Tarnawsky" <beli...@mpx.com.au> wrote:

Quote
>Does anyone know how to convert a 24bit jpeg to 8bit jpeg (or bitmap) with
>some sort of palette optimisation and dithering?

>Do I have to fork out for a 3rd party tool like pixelGraphics library for
>this?

>Is it possible to have a bitmap with 512,1024.... colours as 256 is a bit
>grainy?

>Is all this more difficult that growing hair on a bald man?

You need to get a book on image processing. The technique you are looking for
are "color quantization" - the reduction in the number of colors and
"dithering" - using adjacent pixels to simulate additional colors.

These tend to be fairly complex processes.

John - N8086N
Organizer and Executive Vice President of the
"Vast Right-Wing {*word*97}"
The Vast Right-Wing {*word*97} is now on-line at
http://home.att.net/~miano/{*word*97}.htm
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Re:24bit Jpeg to 8bit Jpeg (or bmp)


Quote
Belinda Tarnawsky wrote:

> Does anyone know how to convert a 24bit jpeg to 8bit jpeg (or bitmap) with
> some sort of palette optimisation and dithering?

> Do I have to fork out for a 3rd party tool like pixelGraphics library for
> this?

> Is it possible to have a bitmap with 512,1024.... colours as 256 is a bit
> grainy?

        ??? Make up your mind - do you want to reduce the number of colors
to 256 or not? Yes, you can have a bitmap with billions and billions of
colors - this exactly what you get if you LoadFromFile a jpeg and then
Assign it to a bitmap, unless you take some sort of steps to make it do
otherwise.

Quote
> Is all this more difficult that growing hair on a bald man?

> Cheers, Damian.

--
David Ullrich

sig.txt not found

Re:24bit Jpeg to 8bit Jpeg (or bmp)


Hmmm.... beginning to sound a bit like Carl Sagan... in any event, billions of
colors would imply dithering to fool the eye into seeing additional colors, but
as I recall, 256^3 yields 16,777,216, the max actual colors available in a
bitmap with 24 bpp, the current high color standard.

Quote
David Ullrich wrote:
> Yes, you can have a bitmap with billions and billions of
> colors--

Wayne Herbert
Manager, Computer Products
Key Maps, Inc.
1411 West Alabama
Houston, TX  77006

Vox:  713.522.7949
Fax:  713.521.3202
Email:  wherb...@rice.edu

"Why is it only drug dealers and software developers call their clients
'users'?"

Re:24bit Jpeg to 8bit Jpeg (or bmp)


Belinda Tarnawsky <beli...@mpx.com.au> wrote in article
<01bd4ce4$749ad300$a35d8...@dialup.mpx.com.au>...

Quote
> Does anyone know how to convert a 24bit jpeg to 8bit jpeg (or bitmap)
with
> some sort of palette optimisation and dithering?

Well it's a bit hard to convert a JPG to 8 bit color palette becuse the
format doesn't support that mode. It's support only 8 bit gray scale.
Any way i advice to consider using tools like Accusoft ImageGear etc.

  Bye, Shay.

Re:24bit Jpeg to 8bit Jpeg (or bmp)


I am working on a shareware application that converts various format types,
including BMP and JPG. It can be used to produce BMPs with all the same
palette too. It is at the beta stage. If you want to see an early copy let
me know, and I'll email you one as an attachment. An earlier version of
PalMerge, that only works with BMPs, is available at the following web site:

   http://www.budget.net/~vantageview/index.html

Bryan.

Quote
Belinda Tarnawsky wrote in message

<01bd4ce4$749ad300$a35d8...@dialup.mpx.com.au>...
Quote
>Does anyone know how to convert a 24bit jpeg to 8bit jpeg (or bitmap) with
>some sort of palette optimisation and dithering?

>Do I have to fork out for a 3rd party tool like pixelGraphics library for
>this?

>Is it possible to have a bitmap with 512,1024.... colours as 256 is a bit
>grainy?

>Is all this more difficult that growing hair on a bald man?

>Cheers, Damian.

Re:24bit Jpeg to 8bit Jpeg (or bmp)


Quote
Wayne Herbert wrote:

> Hmmm.... beginning to sound a bit like Carl Sagan... in any event, billions of
> colors would imply dithering to fool the eye into seeing additional colors, but
> as I recall, 256^3 yields 16,777,216, the max actual colors available in a
> bitmap with 24 bpp, the current high color standard.

> David Ullrich wrote:

> > Yes, you can have a bitmap with billions and billions of
> > colors--

        Thanks. I was never very good at math...

--
David Ullrich

sig.txt not found

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