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WARNING: Block error very high at ... #16

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gunta opened this issue Feb 17, 2016 · 2 comments
Open

WARNING: Block error very high at ... #16

gunta opened this issue Feb 17, 2016 · 2 comments
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@gunta
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gunta commented Feb 17, 2016

Hi, I'm getting lots of "WARNING: Block error very high at ..." messages and compression takes like 2 minutes when trying to compress a 1024x1024 PNG file.

Any suggestions?

@gunta
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gunta commented Feb 17, 2016

This is the image:
http://s17.postimg.org/qw07lyicf/urps.png

Mokosha added a commit that referenced this issue Mar 3, 2016
This fixes #17.

However, it's a preliminary pass that only really operates on the image
included in #16. There are likely better ways to optimize the alpha
used in the images, but I'm not sure what that is. Likely it's better
to use separate alpha dilation than the intensity dilation algorithm
currently used.
@Mokosha
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Mokosha commented Mar 3, 2016

This happens with the BPTC compressor -- it's worth investigating:

WARNING: Block error very high at <608, 252>: (20.09)
WARNING: Block error very high at <276, 736>: (20.49)

These errors are exceptionally high and likely have to do with either how we treat the measurement of alpha errors or actually dealing with compressed alpha blocks themselves.

That being said, here is the compressed output. Doesn't look too bad (although you may disagree. :))

urps-bptc

@Mokosha Mokosha added the BPTC label Mar 3, 2016
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