Converting from exr, tif and psd to jpeg - white background.

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sergo
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Joined: Mon Aug 14, 2006 4:41 pm

Converting from exr, tif and psd to jpeg - white background.

Post by sergo »

Hi dear developers,

I have a big problem with converting "alpha channel"-ed file formats to JPEG with XnView. Here are links to exr and tiff example files.
http://narod.ru/disk/25379646000/camera ... 0.exr.html
http://narod.ru/disk/25379837000/camera ... 0.tif.html

When I convert them to jpeg I get image with the white background. I'm aware of the workaround - disabling "Use alpha channel" checkbox - but it is not acceptable for me, I completelly lose access to the alpha channel it that case, can't see it with 'M' shortcut, for example, can't convert exr to tiff, and so on.
Second workaround was selecting "Convert to TrueColor" in batch convert but that command doesn't help me anymore - since one of the latest version, can't recall exact number.

Converting from exr to tiff goes smoothly - tiff file has untouched alpha channel and everything is fine, but with jpegs... oh, I can't speak about jpeg conversion without a pain...
I don't know if this is a bug, may be it is correct (from developers' point of view) to apply alpha channel to rgb channel when image could not have separate alpha channel, but PLEASE! Give users some option to just IGNORE the alpha channel during conversion! It would so helpful!

Sergo.

P.S. Converting from multichanneled psd file to jpeg is also buggy - some of the additional channels applying to rgb channel of the jpeg.
sergo
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by sergo »

Hi again!

This message seems to have no interest to anyone, I think it's due to file downloading problem, so I've uploaded them to google docs. Here are new links:
https://docs.google.com/fileview?id=0Bw ... y=CKnTrIEG
https://docs.google.com/leaf?id=0BwXBgu ... y=COm34qkL

Does the lack of response in this thread meens that this is not a bug? If this is the case, could someone provide a little help on the subject, please?
What is the right way to convert exr, psd and tiff files to jpeg?

Thank you.
Sergo.
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xnview
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by xnview »

sergo wrote:Does the lack of response in this thread meens that this is not a bug? If this is the case, could someone provide a little help on the subject, please?
No, i'll check the problem soon...
Pierre.
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by xnview »

JPEG can only save RGB, not alpha. So a default background is used.
Pierre.
sergo
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by sergo »

Thank you for reply Pierre.
JPEG can only save RGB, not alpha. So a default background is used.
Why JPEG can not ignore alpha channel then?
marsh
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by marsh »

Hello,
Perhaps the program's export function has the result you prefer in target jpeg. It matches view of not using alpha channel with sample tif (sky blue).
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by xnview »

sergo wrote:
JPEG can only save RGB, not alpha. So a default background is used.
Why JPEG can not ignore alpha channel then?
You means remove the alpha channel?
Pierre.
sergo
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by sergo »

The main goal is to have correct conversion from exr-s and tiff-s to jpeg file.
I really don't know if it is necessary to remove alpha channel from tiff file before conversion but I am sure that this should not be done by-hand, this should be done automatically - tiff's RGB should go to jpg's RGB and tiff's alpha channel should be dropped. I agree that's the dilettante's point of view but I believe that it is possible to accomplish - this bug was not in old versions of xnview (I can't recall which versions, unfortunately, may be 1.8x).

Thank you.
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xnview
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by xnview »

Which bug?? When saving JPEG you would like that XnView remove alpha channel??
Pierre.
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by thibaud »

I guess it's safe to assume that alpha channel should be ignored when converting to formats not providing any support for alpha channels.
by filling the rbg with a plain color with the alpha channel will more than often result in data loss.
sergo
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by sergo »

When saving JPEG you would like that XnView remove alpha channel??
Yes, I would like to remove alpha channel when converting to jpeg.

Thank you, Pierre.
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xnview
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by xnview »

sergo wrote:
When saving JPEG you would like that XnView remove alpha channel??
Yes, I would like to remove alpha channel when converting to jpeg.
Right, in older version, the alpha was removed, but many users was disapointed. I'll add an option...
Pierre.
sergo
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by sergo »

That would be incredibly cool! :)
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by xnview »

Please try 1.98 beta3
Pierre.
sergo
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Re: Converting from exr, tif and psd to jpeg - white backgro

Post by sergo »

Thank you, Pierre, but I see no difference. Is there some option to ignore/remove alpha channel?
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