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Warp wrote:
> Severi Salminen <sev### [at] not_thissiba fi> wrote:
>
>>But I doubt if there are many professionals who can hear the
>>difference between 16/44 and 24/96 _all other things being equal_.
>
>
> Believe me: There are.
Well, there might be but I believe you _fully_ not until I have heard
the difference myself (I don't consider myself as being a "layman" in
this regard). But as I have not yet used such equipment I can't comment
more.
Severi "if I can't hear it, nobody can ;-)" S.
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> Can't you use different compression levels on different parts of the image
> in JPEG2000?
Yes, you can, even in two different ways.
1.) j2k can consist of tiles of eg 128x128 pixels (or whatever dimension you
like)
and the decompressor can be reinitialized (for different quality settings) for
each tile.
2.) The ROI-tag (Region Of Interest) to store a part of the image even in
higher
resolution.
BUT, none of those nine test images uses any of these features and already
with them you'll find not much reliable software to decode them and with those
*extended* features (but still ISO part 1 standard) the situation becomes
really worse.
I really do not want to advertise this Kakadu thing, but it was the only one
that
did it right.
> > The JPEG2000 file header is just XML
>
> And I thought they wanted the file to be as small as possible...
>
Well, I do not know how the ISO works...
> > And about the 16bit/8bit per channel color banding controversy. Somehow this
> > reminds me on people who seem to think a 64bit CPU is twice as fast as a
> > 32bit one.
>
> I wouldn't compare it to that.
> I would compare it to 16-bit vs. 24-bit sound sampling. A layman does
> not hear any difference at all between 16-bit (eg. CD) and 24-bit sound,
> but professionals would not work with anything less than 24. The same
> goes for 44kHz vs. 96kHz sample rate...
Yes, sure you are right and your example is much better. It was just the case
that a few minutes before writing this I did read a posting where somebody
seriously did say this.
-Ive
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> QuickTime decodes all images except image 6 (just blank) correctly.
> GraphicConverter does decodes them all without problems.
>
Thanks, and good to hear that at least in the mac-world it is not such
a big problem.
-Ive
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Warp wrote:
> Severi Salminen <sev### [at] not_thissibafi> wrote:
>> But I doubt if there are many professionals who can hear the
>> difference between 16/44 and 24/96 _all other things being equal_.
>
> Believe me: There are.
Wouldn't that involve being able to hear sounds at a frequency higher than
22 kHz or with a higher dynamic range than 100 dB?
Do you have a link to a 24/96 sample file I could use to compare? I suspect
my amplifier and speakers drop off quite soon after 20kHz though, and the
SNR is probably less than 100dB, making it rather pointless :-)
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>
> Wouldn't that involve being able to hear sounds at a frequency higher than
> 22 kHz or with a higher dynamic range than 100 dB?
Not really.
For example, there are some amplifiers that can work from 0 Hz to 200
KHz (hi ends ones... and far more than a month salary worth...). Some
can say that it is stupid, because it is far beyond the ears range. But
there are some signal modulations that are generated at aprox. (I don't
really remember) half the max frequency of the amplifier. By setting
that max frequency that far higher, you can be sure that it does not
affect the frequency range you can hear.
For hearing the difference between 16/44 and 24/96, on some signals, a
lot of people can! Even those that are not professional.
I explain:
The ear is more sensitive that most think.
If you connect a fonction generator to your amplifier, you can hear the
difference between a sin waveform and a triangular waveform at 20 KHz.
Record it on a CD, and you can no more! There is not enough precision at
high frequencies. On a 24/69 signal, you can.
regards,
--
Laurent ARTAUD (lau### [at] freefr)
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laurent.artaud[AT]free.fr" <"laurent.artaud[AT]free.fr wrote:
> > Wouldn't that involve being able to hear sounds at a frequency
> > higher than 22 kHz or with a higher dynamic range than 100 dB?
>
> Not really.
> For example, there are some amplifiers that can work from 0 Hz to 200
> KHz (hi ends ones... and far more than a month salary worth...). Some
> can say that it is stupid, because it is far beyond the ears range.
> But there are some signal modulations that are generated at aprox. (I
> don't really remember) half the max frequency of the amplifier. By
> setting that max frequency that far higher, you can be sure that it
> does not affect the frequency range you can hear.
>
> For hearing the difference between 16/44 and 24/96, on some signals, a
> lot of people can! Even those that are not professional.
> I explain:
> The ear is more sensitive that most think.
> If you connect a fonction generator to your amplifier, you can hear
> the difference between a sin waveform and a triangular waveform at 20
> KHz. Record it on a CD, and you can no more! There is not enough
> precision at high frequencies. On a 24/69 signal, you can.
I will have to try that one out when I get some sound editing software
installed (just reinstalled Windows). What CD player did you use to play
back the audio CD?
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> I will have to try that one out when I get some sound editing software
> installed (just reinstalled Windows). What CD player did you use to play
> back the audio CD?
>
I did not test it myself, sorry if I may have implied it unknowingly.
Anyway, my explanation of the process was simplified for a text demo.
Note that (if I wasn't clear) a function generator is an electronic
device (I don't have any, it's quite expensive) used in laboratories to
test other electronic devices. It have nothing to do with any software
in the sense that the signal stays analogous all the way and is in no
way digitalized.
On the other end, using a software to generate the waveforms to create
the CD is a far better way than trying to sample the function
generator's output.
Testing the 24/96 signal would be harder:
1) you have to find a software who can generate it ;
2) you have to play it.
I don't know if any authoring software allows to make DVD-audio, but it
would be a solution to test it (note that a DVD-audio player is not
cheap -- I know for sure: I have one... -- and the amplifier must be
good enough behind...).
Anyway, if you can test it, let me know.
Regards,
--
Laurent ARTAUD (lau### [at] freefr)
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Ive wrote:
...
> The Gimp (and the complete linux world) seems to be completely
unaware of
> color management issues. :(
...
IIRC a linux magazine recently mentioned that Gimp in the not so
distant future will support color profiles (v2 ?).
And some quick googling for "Gimp ICC" shows that there already
seems to exist plug ins / extra modules for Gimp that deals with
color management.
http://www.google.com/search?q=GIMP+ICC
Tor Olav
--
Tor Olav
http://subcube.com
http://subcube.net
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scott wrote:
...
> What CD player did you use to play back the audio CD?
...
Maybe he used a Super Audio CD (SACD) or a DVD-Audio player ?
--
Tor Olav
http://subcube.com
http://subcube.net
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On 9 Mar 2004 10:38:53 -0500, Warp <war### [at] tagpovrayorg> wrote:
>Ive <ive### [at] lilysoftcom> wrote:
>> Imagine a picture with a smooth sky gradient and some small wires in the
>> foreground. JPG will introduce some artefacts (and color banding) in the sky but
>> J2K will tend to blur out the wires and make them vanish - so anyway, a loss of
>> information is a loss of information.
>
> Can't you use different compression levels on different parts of the image
>in JPEG2000?
I think you can do with with JPEG too.
>
>> The JPEG2000 file header is just XML
>
> And I thought they wanted the file to be as small as possible...
>
>> And about the 16bit/8bit per channel color banding controversy. Somehow this
>> reminds me on people who seem to think a 64bit CPU is twice as fast as a
>> 32bit one.
>
> I wouldn't compare it to that.
> I would compare it to 16-bit vs. 24-bit sound sampling. A layman does
>not hear any difference at all between 16-bit (eg. CD) and 24-bit sound,
>but professionals would not work with anything less than 24. The same
>goes for 44kHz vs. 96kHz sample rate...
It certainly is a tricky area this. I know I have seen banding in
images, and I know the solution is greater colour depth - but boy is
it ever hard to come up with an example. Believe me I've tried.
Now even though I've failed to come up with an image example does not
mean it does not exist. A quick Googling will show that plenty of
other people think they way I do. Mind a lot think otherwise too.
--------------------------------
My First Subgenius Picture Book:
http://www.imbjr.com
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