lossless compression of in camera processing - Feature Requests - CHDK Forum
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lossless compression of in camera processing

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Offline robermalek

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lossless compression of in camera processing
« on: 23 / September / 2012, 17:39:24 »
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Hi all. I would like to recommend a feature that I would be interested in and maybe others though I have not seen it listed.
The feature I would like to see if possible, is not just compression of raw, which was part of the selection list, but compression of the in camera processing without a lossless jpeg compression method. Maybe jpeg 2000 or lzw for instance ? pardon me if this was discussed in the past and i missed it. - robert
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Offline waterwingz

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Re: lossless compression of in camera processing
« Reply #1 on: 23 / September / 2012, 18:06:36 »
No need to post this same request twice.   The CHDK devs follow all threads.

Short answer - this has been talked about.  However,  the JPG compression in a Canon P&S camera is handled by the DSP chip - not the ARM chip that CHDK gets access to.  In theory,  we could jpeg 2000 or lzw compress CHDK DNG images but it would be slow.  And you'd really like to introduce the compression after the DSP has processed the image for lens distortions.
« Last Edit: 23 / September / 2012, 18:09:41 by waterwingz »
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Offline robermalek

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Re: lossless compression of in camera processing
« Reply #2 on: 23 / September / 2012, 21:56:13 »
Hello. I said below...

The feature I would like to see if possible, is not just compression of raw, which was part of the selection list, but compression of the in camera processing without a lossless jpeg compression method.

I MEANT TO SAY, WITH A LOSSLESS JPEG  COMPRESSION METHOD.

Waterwingz before I posted, I did do a search and didn't see it there.
In addition, I didn't post twice. If my post went up twice, well, computers and software do make mistakes quite often.

Thank you for your knowledgeable reply to my question.
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Offline waterwingz

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Re: lossless compression of in camera processing
« Reply #3 on: 23 / September / 2012, 22:13:03 »
Quote from: robermalek on 23 / September / 2012, 21:56:13
The feature I would like to see if possible, is not just compression of raw, which was part of the selection list, but compression of the in camera processing without a lossless jpeg compression method. I MEANT TO SAY, WITH A LOSSLESS JPEG  COMPRESSION METHOD.
Agreed.   That would be very good.  But so far nobody has figured out how to do it. Or if its even possible to do with the camera's ARM processor with the RAM space and processing time available.

Quote
Waterwingz before I posted, I did do a search and didn't see it there.
In addition, I didn't post twice. If my post went up twice, well, computers and software do make mistakes quite often.
Not that it matters much but this is what I was referring to :
http://chdk.setepontos.com/index.php?topic=8727.msg91225#msg91225
http://chdk.setepontos.com/index.php?topic=547.msg91223#msg91223
Slightly different versions of the same post.  Most people don't realize that there are only about 10 people who routinely answer questions on this forum and, as the message volume is pretty light, they tend to read all posts.  There's no problem with how you posted - but sometimes we have to remind people that multiple posts of the same thing do not get a better response.


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Offline robermalek

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Re: lossless compression of in camera processing
« Reply #4 on: 24 / September / 2012, 01:37:45 »
Hi waterwingz. Well, I figured that since I wasn't commenting on what was there, but what could have been there, a new post would be fitting. If I was commenting on what was there, I would have kept it there.
Anyway, I'm sure you understand my logic as I understand your helpful suggestion since posting once saves time anyway. thank you for all the time and effort you give so many people. - robert
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