Zitat:
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Zitat von gpo
JPG ...ist definitv immer... verlustbehaftet...!
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FALSCH! Aus
JPEG-FAQ Part1:
Subject: [13] Isn't there a lossless JPEG?
There's a great deal of confusion on this subject, which is not surprising
because there are several different compression methods all known as "JPEG".
The commonly used method is "baseline JPEG" (or its variant "progressive
JPEG"). The same ISO standard also defines a very different method called
"lossless JPEG". And if that's not confusing enough, a new lossless
standard called "JPEG-LS" is about to hit the streets.
When I say "lossless", I mean mathematically lossless: a lossless
compression algorithm is one that guarantees its decompressed output is
bit-for-bit identical to the original input. This is a much stronger claim
than "visually indistinguishable from the original". Baseline JPEG can
reach visual indistinguishability for most photo-like images, but it can
never be truly lossless.
Lossless JPEG is a completely different method that really is lossless.
However, it doesn't compress nearly as well as baseline JPEG; it typically
can compress full-color data by around 2:1. And lossless JPEG works well
only on continuous-tone images. It does not provide useful compression of
palette-color images or low-bit-depth images.
Lossless JPEG has never been popular --- in fact, no common applications
support it --- and it is now largely obsolete.
Man kanns doch finden, ist aber wirklich sehr spezialisiert:
ImagXpress
Zitat:
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Zitat von gpo
und die % Prozentwerte...
habe ich aus alter Tradition geschrieben, denn einige Programme zeigen sehr wohl auf dem regler Prozentwerte an....andere nicht!
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Aus
JPEG-FAQ Part1:
Most JPEG compressors let you pick a file size vs. image quality tradeoff by selecting a quality setting. There seems to be widespread confusion about the meaning of these settings. "Quality 95" does NOT mean "keep 95% of the information", as some have claimed. The quality scale is purely arbitrary; it's not a percentage of anything.