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Posted by Lon Obers on 07/03/07 22:31
Richard Crowley wrote:
> "Léon Obers" wrote ...
> In my defense, I was attempting to observe that it is not possible
> to eliminate ALL artifacts of heavy, lossy compression, no matter
> how much computing power you throw at it. (Hence the term:
> "lossy"). In some very "busy" scenes in a movie, the compression
> can't keep up even up to the max limit of the format. That is just the
> way they had to design it for compatibility with all DVD players, etc.
As a photographer I am not used to film / movie, but in basic image
compression used in film or pictures are in accordance with each other.
As for film, an extra difficulty to overcome with fast followed changes
in scene.
In several years interpolation techniques has developed at a high level.
That's why you can find so many "standards" and codecs. Every new method
and approach is to be used in advantage of the user.
As for images for photography the emphasis is more in interpolation
techniques to avoid artifacts by converting RAW data from a Bayer
pattern (the same for camcorder with only one imager) and by lowering
noise levels at more high ISO ratings, than compression techniques.
Fact is that in accordance with film and photography the negative
aspects of image recording has to be lowered as much as possible.
One approach does a better job than the other.
(Thats why I am comparing some of the applications).
Me myself am in digital photography business from about 1993 and I am
much surprised by the big quality steps which are made in last years,
thanks too, to many good interpolation techniques used in "building up"
a new image from a more basic "bad" recorded image.
So, I think you and I do accept fully the advantage of using
"deblocking" tools as a usefull tool, and every other "restoration"
technique to rebuild "destroyed" images.
Did read some scientific articles in past, with amazing techniques to
rebuild new images out of nearly “nothing” by a method of “what to
expect” in what the image should be found out from a scene, rather than
a "dry" calculation only.
> OTOH, I am surprised that ANY ripping software is so shoddy that
> it can't recover at least as much of the image as any common DVD
> player does on the fly. That seems inexcusable.
I don't know if it is. I want to make a smaller copy for using on the
web. Looking high or low, it is more bad as the original already of the
fact it is more small. Just try to find a balance between best options
in quality by more or less not to big data files.
But for our job I shall aks the base "mother" material of the movies to
be ripped. That is a better quality (HD) as the DVD version to use as
base for ripping.
Thanks for your input.
--
Vr.groet - regards, Léon Obers
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