Cannot save 48 bits SGI as PNG or FLIF

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omniplex
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Cannot save 48 bits SGI as PNG or FLIF

Post by omniplex » Wed May 11, 2016 6:30 pm

My first test with XnViewMP 0.79: Parkjoy frame 200 (a 48bits RGB SGI): Counting colors apparently works, more than 1,400,000. Save as FLIF failed, the result was an empty file (0 bytes) after some minutes. Save as PNG also failed, I got a 24bits PNG instead of a 48bits PNG. And apparently no PNG options. I also checked WebP, but without (obvious) options to request lossless I didn't test what actually happens if an image is saved as WebP.

Is that as it should be, XnViewMP cannot save more than 24 (or 32 with alpha) bits per pixel?

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Re: Cannot save 48 bits SGI as PNG or FLIF

Post by xnview » Tue May 17, 2016 8:45 am

omniplex wrote: Is that as it should be, XnViewMP cannot save more than 24 (or 32 with alpha) bits per pixel?
it can't save more than 24/32 bits per pixel
Pierre.

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omniplex
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Re: Cannot save 48 bits SGI as PNG or FLIF

Post by omniplex » Tue May 17, 2016 6:50 pm

xnview wrote:
omniplex wrote: Is that as it should be, XnViewMP cannot save more than 24 (or 32 with alpha) bits per pixel?
it can't save more than 24/32 bits per pixel
Oops, I always thought that only classic is limited to 32 bits.:shock: Are you planning to support up to 64 bits per pixel in MP or even classic?

It is not that I really "need" it on my 2011 laptop, but there is a general trend to offer more bits per pixel, and to use some linear transformations instead of convoluted gamma and/or color profile tricks trying to squeeze more than 256 plausible values per channel into only 8 bits. Even BMP can now do 3*10 bits RGB + 2 bits alpha for RGBA.

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