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Old Nov 13, 2002, 4:30 AM   #1
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Default Image compression software-anyone use?

Does anyone use MPZ (Myphotozip) for compressing image files? I would like to know what they think of it, who would/should use it etc. I am using trial for 30 days and it really does a great job compressing a picture file but it seems slow to me. Anybody have any comments about it in any way? My initial reaction is that someone who wants to email several or many pics would probably use it but for a few it's not worthwhile! Thanks in advance for any replies.
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Old Nov 13, 2002, 6:13 AM   #2
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How much does it compress a jpg file?
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Old Nov 13, 2002, 7:22 AM   #3
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Not only how much does it compress a JPEG, but how much additional loss does it introduce?

I would run away from any program that claimed to compress JPEGs - they are already compressed with a time-tested algorithm. If a program existed that was able to compress them further by any significant amount, I would be very surprised. Though your comment that it is slow does add a bit of credibility to the claim.

Try compressing a few JPEGs with PKZIP - pretty much always the result will be larger than the original JPEG. Not much larger, just by the amount that PKZIP uses for "header" information.
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Old Nov 13, 2002, 7:33 AM   #4
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I agree with Bill, I use both Winzip and PKzip and compressing a jpeg produces minimal compression. That is why I ask how much does it compress.
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Old Nov 13, 2002, 9:44 AM   #5
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Default MPZ-photo compression

I'm not a technical person but I think if you make the correct choice in compressing a jpg for a clear image result it will be a 5:1 ratio by MPZ. Any larger compression will result in a blur. To use compression of jpg is apparently mostly for sending an email attachment quickly due to the smaller file. The receiver needs to download a free viewer or you send it along. They have a program for multiple compression I think but it sure must take lots of time.Mostly it's for larger convert from RAW or TIFF I believe.
I don't think I'll continue with the program but anyone can go to their web site for a 30 day trial. You can find it on Steve's main page under Digicam Software and then Image Viewing Software. I'll try to paste the url.
http://www.steves-digicams.com/digsoftware_viewers.html
Thanks much.
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Old Nov 13, 2002, 10:50 AM   #6
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Compression utilities like WinZip are lossless, they look for repeated bytes in lines or blocks of code and send one byte saying 'there are x bytes, each of the same value y.

So forget it for jpegs BECAUSE PHOTO IMAGE DATA IS RANDOM and has virtually no repetitive structure after first compression. The next problem is image data does not efficiently pack to deliver in email protocol. Again, the file data is random and not text looking with redundant spaces and repeated text characters. This is why ftp is used for moving binary files around.

This programme might somehow convert random data to a text type format which might email better. But I can't imagine the files would be smaller.

The big disadvantage seems to be a proprietary non standard file format requiring a special viewer.

Remember, if you're emailing cam pics to view, you only need pc monitor resolution so downsampling the file is more effective 'compression' as it is removing detail not required. Add JPEG afterwards and your files become very small!
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