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MichaelKirk Offline Upload & Sell: Off p.1 #1 · Compression Software question - ftp Has anyone used ALTools compression software (freeware)? I need to start sending images to an ftp server compressed. Looking for some freeware and came across this ALZip rated very high on CNet http://www.altools.com/ALTools.aspx Simple to use, but I am only getting 1% compression on my files (jped/tiff) and not sure why. Something I may be doing (but there is no way to really mess up using this software) or are the files I am using already compressed and cannot be compressed any further?? I am shooting Nikon RAW and the camera is set up at lossless compression. Importing as DNG and after all edits output to either tiff or jpeg. I thought that the copmpression software would compress final images even further?? Michael Nov 21, 2008 at 10:46 PM

John Patrick Offline Upload & Sell: Off p.1 #2 · Compression Software question - ftp JPEG is an already-compressed format. Basically, it's probably compressing just EXIF and the occasional few bytes. Not too sure about TIFF, though. Can I ask why you feel the need to have compression? Set it up and let it run, or perhaps re-evaluate your need to upload hi-res images (not sure if you're uploading for web, storage, submittal, or what). John Nov 21, 2008 at 10:52 PM

billk55 Offline Upload & Sell: Off p.1 #3 · Compression Software question - ftp In a word, no. ZIP is a standard algorithm that is the same for all types of files. The way JPGs are compressed takes into account the fact they are images, and actually does some reasonably smart inter-scanline compression. ZIP takes a (in this case binary) file, and looks for common bit patterns. Great for text (think how often the letter 'e' is used in English). Ineffective for binary. And, ZIP is lossless, which is nice (and necessary for text), whereas JPG can be very lossly if you crank up the compression. Nov 21, 2008 at 10:55 PM

aborr Offline Upload & Sell: Off p.1 #4 · Compression Software question - ftp It depends what you are sending. It makes sense to use zip or other compression when uploading text files, or even raw images over ftp. If you ftp files that are already compressed, such as jpeg images or mpeg audio or video, you gain nothing adding by adding another layer of compression to the stream. All of the characteristics of 'normal' files that make zip and other similar compression algorithms effective are missing from files that have already been compressed using jpeg or mpeg. In fact, if you're uploading jpeg's, you'll probably find that the number of bytes sent over the line when you use ftp plus zip/unzip is a few per cent _larger_ than if you just used plain ftp alone. Al Nov 22, 2008 at 07:07 AM

nathanlake Offline Dedicated FM Upload & Sell: On p.1 #5 · Compression Software question - ftp Your example picture shows very little savings. Not really worth it in my opinion. Nov 23, 2008 at 12:18 AM

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