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Re: [tlug] OGG & MP3



Godwin Stewart wrote:

Lossless compression does not have that quality degradation concern.
But does it really exist? Is FLAC, for example, *really* lossless in
absolute terms or are the losses outside the human audible range (much
like they are in OGG)? IOW, if you compress an uncompressed stream such
as PCM WAV and then re-uncompress the compressed stream, do you get
back exactly the same data as you started with?

I would also like to know the answer to that.  In the case of image
files, working with .tif images, every pixel is preserved no matter how
many times you resave something.  I did some work for a friend once and
put text onto a telephone pole in the photo (for the cover of the book
"At Mama-san House").  Thinking it was finalized, I didn't save the
intermediary steps and then he requested that the text be changed.  At
first I was thinking "Oh no... am I going to have to go through the
whole editing process again?..." but as I had the original photo, all I
had to do was copy over the exact block of pixels that made up the text
and I was back with a blank telephone pole and ready to write new text
over it.  (Yes, I do realize that if I had been working with layers,
that would have been automated...)

Of course, that's .tif to .tif - I'm not sure if things are perfect
between lossless formats....

Lyle




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