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List:       kde-kimageshop
Subject:    Re: A survey about tile compression algorithm - results
From:       Dmitry Kazakov <dimula73 () gmail ! com>
Date:       2010-06-26 19:27:27
Message-ID: AANLkTikmh1V9vKXMoNG1-Wv-SYTnlG4CbPQ4YDcdbeLC () mail ! gmail ! com
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> Ooh! Numbers! But math-challenged as I am -- what conclusions do you
> suggest?
>

1) For most purposes, including swapper, we need compression only (undo is
not really a common usecase). So LZF with linearization is the best choice.

2) Linearization of colors makes compression ratio and compression speed
better. It injures decompression speed a bit (8%), but as defined in 1), it
is not a common usecase for us.

3) The tile fits into the cache of my cpu quite well, so memcpy operation on
a single tile is very cheap! It is 1/90 of compression time and 1/40 of
decompression time.

4) The best compression we can achieve on full-color images (like a tile
from hakonepa.png) is 75% (compressed/uncompressed*100%)

5) A tile, filled with color will be squeezed to 5% of original.

-- 
Dmitry Kazakov

[Attachment #5 (text/html)]

<br>
<div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt \
0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Ooh! Numbers! \
But math-challenged as I am -- what conclusions do you suggest?<br> \
</blockquote><div><br>1) For most purposes, including swapper, we need compression \
only (undo is not really a common usecase). So LZF with linearization is the best \
choice.<br><br>2) Linearization of colors makes compression ratio and compression \
speed better. It injures decompression speed a bit (8%), but as defined in 1), it is \
not a common usecase for us.<br> <br>3) The tile fits into the cache of my cpu quite \
well, so memcpy operation on a single tile is very cheap! It is 1/90 of compression \
time and 1/40 of decompression time.<br><br>4) The best compression we can achieve on \
full-color images (like a tile from hakonepa.png) is 75% \
(compressed/uncompressed*100%)<br>  <br>5) A tile, filled with color will be squeezed \
to 5% of original.<br><br></div></div>-- <br>Dmitry Kazakov<br>



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