You CANNOT lose quality with RAR or ZIP no matter what settings you choose. You will always retain exactly the same output from them that you put into them. They are completely lossless compressions.

Remember that RAR and ZIP are generic file compression utilities. They have no idea what kind of data the files contain and therefore don't take any shortcuts by tossing out what might be superfluous or unneeded information. They can't. Otherwise they'd be useless. Imagine a lossy compression of a company's yearly bugdet spreadsheet ... send that to the boss with a note attached "well, the compression was mild so only about 5% of the numbers are scrambled". No, that just wouldn't work.

Both RAR and ZIP are lossless compression schemes - you get out exactly what you put in.

RAR was originally developed to do a better job of losslessly compressing media files than ZIP - it uses special methods for media files that ZIP doesn't have, and achieves better compression rates on media files because of this. (RAR and ZIP are pretty much the same as regards compression rates on other, general, files where they use similar compression methods.)

The advantage of RAR is that it achieves better compression on audio and video files. The disadvantage is that you need to be sure that the person you are sending the .RAR files to either has a decompressor for them or is willing and/or able to install one. With ZIP you needn't worry because the ZIP decompressor is built into Windows (from XP onwards at least).

Mark

YEARS AGO I used rar to transfer media files. When using the special media compression there would be issues. But that was ~6/7 years ago.

FYI, rar can't handle huge (several GB) zip files. Found this out when I backed up a whole folder from my computer to a DVD as a zip. No rar program would touch it, always said file was bad. Zip programs worked just fine.

I use RAR all the time on extremely large files with no problems. RAR will also automatically split archives into DVD-sized chunks which I sometimes use for backing up projects.

i vote for RAR, file structure is easy to explain to non-tech people but are daily computer users.

I have been one of those people who were unwilling to adopt RAR for business use. Asking a group of people in a corporation to all start using RAR (which would force them to pay for it and involve a global IT department) was just not going to be possible.

The take-away here is that you need to ask your client which they prefer and gently point out that the RAR compressed files have the same content but are smaller.

You probably need to push these up to their FTP server, or allow them to pull them down from your server. If they can't make a decision, post both versions. Zip is more universally openable.

Winzip has a very strong encryption option but the client would need winzip to decrypt the files.

Rob Mack

i don't see why size would be a huge issue. unless you're dealing with tens (maybe hundreds) of TB's a data, a 3-5mbs 'net connection or fedexing a physical drive would be the best bets. If you're trying to be cheap, then that comes with the territory: size, price or speed.

Out of curiosity, I ran a few numbers.

On an m2t clip of 82.7MB, WinZip reduced the size by 2%, WinRar by 3%.

On the same clip but in DV format (now 94.4MB), WinZip reduced it by 6% and WinRar by 11%.

Both Winzip and Winrar were set to maximum compression. WinRar took maybe 5x longer.

So my impression is that, for a heavily-compressed data structure (such as m2t) then the benefits of either format are almost negligible. They do, however, allow one to put a password on the file.

My project is complete and away in RAR format. Thanks to all who offered their insight.

I found the following numbers using RAR & ZIP.

Original 29.29 second clip - 111, 329 KB

RAR using "best" settings - 68.670 KB
TIme: 1:30

ZIP using "best" settings - 101,887 KB
Time: :28

RAR is roughly 66% of the original size. Certainly a time saver for multiple clips and slower internet access.



Thanks everyone!