Re: WHOA!! Backup the JPG truck...

[P3D Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Mon, 08 Sep 1997
>From: P3D Jonathan Gross  responds:
>......................
>On the other hand, lossy compression techniques, such as JPEG and JPS,
>when they dont find enough redundancy in an image,  blur the colors to
>create some.  Apply the name list metaphor to JPEG, and Jonathan Gross
>and Larry Berlin might come out John Grossman and Lance Berman.  Close
>enough? 
>
>The point is that I think low quality stereoscopic images on the web are
>a turn-off for both seasoned stereophiles and the newly curious.


The whole point isn't that there is loss in JPEG. That is a non-issue. The
mark of a professional isn't that they avoid JPG altogether but use it
wisely with knowledge of what going too far will do. It's a compromise issue
typical to any other numerous compromises that get used on a computer. The
freedom provided by use of JPG for stereo by letting one have the high res
versions available to edit and a compressed means of sharing on the internet
is very desirable. A JPS image isn't automatically a low res image by any
stretch of imagination. Even low levels of compression are smaller than any
of the other compression methods applied to a full resolution format. That's
*advantage* and it exists before losing track of the available image data.

The losses in the name list that you use as an example is only applicable to
using amounts of compression quite a bit higher (maybe 60% compression and
up) than would be used on the average by any intelligent persons. The fact
that there is an extreme is no grounds to throw out the whole thing. JPS and
JPG are useful because some amount of compression can be used without
creating a problem in a stereo image.

I fully concur that too much compression should be avoided, but no
professional would throw out the whole scheme just because a better method
hasn't been written yet that is freely available for use. When it's
available, I will be quite happy to try it out. 

I believe it should no longer be reasonable to even hint that *JPG shouldn't
be used at all* as that's a totally unreasonable and unprofessional
assumption. There is no reason to debunk JPG factors which are well known,
in order to sell or make a point about something else. It's far more
productive to just bring up your real subject and leave out the direct
disparagements. 

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/
http://3dzine.simplenet.com/


------------------------------