[rescue] Re: SGI Onyx4 - uses ATI graphics chips (sigh)

Fri Aug 22 12:40:22 CDT 2003

I'm not familiar with film/graphic work... if compositing is
displaying the image for the human eye, then most people can not
see beyond 24 bit color.... so how is it highly visible ?

Calculation wise I can see... but that is not done in video memory
and is not dependant on display depth capability...

Or are you talking when digitizing something in (which still you
do to main memory and the depth is separate from actual display depth) ?

-- Curt

>X-Sender: arnach at arnach.com@pop.directnic.com (Unverified)
>Date: Fri, 22 Aug 2003 13:09:22 -0400
>To: "Curtis H. Wilbar Jr." <rescue at hawkmountain.net>, The Rescue List 
<rescue at sunhelp.org>
>From: Aaron Finley <arnach at arnach.com>
>Subject: Re: [rescue] Re: SGI Onyx4 - uses ATI graphics chips (sigh)
>
>
>24-bit vs. 32-bit is highly visible when doing compositing. In terms of 
>calculations, many film applications use 64-bit (!) color.
>
>-- Aaron
>
>At 01:02 PM 8/22/2003 -0400, you wrote:
>>All this is logical... however, once processed, the difference in
>>display on a 24 bit display vs a 32 bit color dispaly is probably
>>imperceptable.... and didn't this whole thread start on what the
>>display was displaying... not what amount of significant bits were
>>used in processing ??? or is my memory dropping bits ?
>>
>>-- Curt
>>
>> >Date: Fri, 22 Aug 2003 12:25:05 -0400
>> >From: Phil Stracchino <alaric at caerllewys.net>
>> >To: The Rescue List <rescue at sunhelp.org>
>> >Subject: Re: [rescue] Re: SGI Onyx4 - uses ATI graphics chips (sigh)
>> >Mail-Followup-To: The Rescue List <rescue at sunhelp.org>
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>> >On Fri, Aug 22, 2003 at 05:59:53AM -0700, Lionel Peterson wrote:
>> >> Well, I believe I conceded the point about storing the detail for
>> >> off-line processing, but my statement still stands, what is the point
>> >> of producing a system to (display) greater detail than the human eye
>> >> can resolve? Are you entertaining aliens with higher resolution optical
>> >> sesnses? ;^)
>> >
>> >
>> >There's another point at issue here.
>> >
>> >Let's suppose, for the sake of argument, that the human eye can resolve
>> >24 bits of color.  (I know I can tell the difference between 24-bit and
>> >16-bit color.) Suppose also that whatever processing you do on your raw
>> >data to generate your final image introduces sufficient rounding errors
>> >and interpolation artifacts that you lose the integrity of the least
>> >significant 4 bits per color channel.  If you started out with, say, 48
>> >bits of color information (16 bits per channel), you now have 36 bits of
>> >good data (12 bits per channel).  If you started out with 24 bits (8
>> >bits per channel), you now have 12 bits (4 bits per channel) of good
>> >color data in your final image, and it probably looks like hell.
>> >
>> >Any signal processing introduces noise into the data, because you're not
>> >working with infinite precision.  The secret of getting good results out
>> >of imperfect data processing is to start out with sufficient precision
>> >that the final noise level ends up below your perceptible noise floor.
>> >If you need an answer to six significant digits, and expect to lose
>> >two digits of precision during the calculation, start out with *at
>> >least* eight significant digits of data.
>> >
>> >
>> >--
>> > .*********  Fight Back!  It may not be just YOUR life at risk.  *********.
>> > : phil stracchino : unix ronin : renaissance man : mystic zen biker geek :
>> > :  alaric at caerllewys.net : alaric-ruthven at earthlink.net : phil at latt.net  :
>> > :   2000 CBR929RR, 1991 VFR750F3 (foully murdered), 1986 VF500F (sold)   :
>> > :    Linux Now!   ...Because friends don't let friends use Microsoft.    :
>> >_______________________________________________
>> >rescue list - http://www.sunhelp.org/mailman/listinfo/rescue
>>
>>
>>Curtis Wilbar
>>Hawk Mountain Networks
>>rescue at hawkmountain.net
>>
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Curtis Wilbar
Hawk Mountain Networks
rescue at hawkmountain.net

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