does anyone know if putting wave files into a RAR to send them degrades the audio quality?

word up

pls+thx

It certainly shouldn't.

forgive my retardation, but where does the file information go?

compression can really degrade and then bring back all the file information?

(I'm usually pretty sharp with the audio stuff... but file/data compression... um.. don't quite get it)

Your rar file will not show much file size compression. Maybe 2-3%.
The only benefit is really to have them all in one file.

Yeah, if it is something that you need to maintain absolute audio integrity, I'd just set up an FTP and have the person on the other end dl it directly. Anytime you do .rar or whatever, you're losing something. It might be minuscule, but its loss somewhere.

But aren't the files restored when you "unpack" them?

Timmyjoe hit the nail on the head. You will get very little compression of a lossless file using WinRAR. The WinRAR compression is supposed to be lossless, but I take that as "nominally lossless" and thus there is a miniscule amount of loss probably, like FR said. Frankly, I don't think it's enough that anyone would or could ever notice it, but if you want truly lossless, send each file separately.

Ok. thanks for the info. Yeah, in this case it needs to maintain full quality. So I guess it's ftp.

thanks

You will not lose information, it is lossless.

Compression for mp3s works differently than compression in zip or rar files. Just go read about it.

Consider this, if RAR or ZIP was 'lossy', then any program that was compressed wouldnt work when you unzipped it and ran it..

this is why the % of compression can vary across files... it is due to the ability of the program to compress in a lossless way...

man, people just say shit....

Thanks, I thought I was losing my mind for a second.

And for the record, I just did a test zip of a 5.5 MB wav file that brought it down to 4.4 MB. Does my math suck, or is that closer to 20% than "2 - 3%" like timmy said? I guess it may vary for larger files, but it has been my experience with zipping files - something we do a lot to deliver to clients - that you gain far more by zipping larger, "lossless" or uncompressed files than you by zipping things like mp3s.

So, your contention is that every 1 and 0, after it is unpacked, is identical to the file before it was packed? I know this is theoretically possible, but my understanding is that these programs use some rounding algorithms to compress the files, which to me means the files cannot end up exactly like the original file.

It depends on the file, and how much of the file is redundant.

Aaaannnnd there is often a lot of redundancy in lossless, uncompressed audio and video files. I just zipped a 53 MB wav file down to 24.6 MB.

Yes, that is what lossless means- if a computer program is missing a single letter or line of code.. no workee, right? It has to be lossless.

Compression can simply mean more economical representation of information.... so instead of saying

a) "I like bananas because bananas make me go bananas" - you could represent it like

b) "I like * because *s make me go *s" along with the info that says something like : c) "* = banana"

When the 'compressed' file is processed then it simply rewrites each * as banana on output. Obviously the savings (amount of compression) is equivalent to something like 'a-(b+c)'. That would be an example of lossless.

Another way to more economically represent information is to not represent all of it, but only what functionally matters. So for instance, mp3 compression works off of psychoacoustic theories of human hearing - to determine what bits of information can be left out without affecting (or minimally) affecting perception. JPEG etc. work on similar principles of approximating the input.

I think the bigger question here, is would you trust something that absolutely could not have digital decay any further than the original wav file, to be sent to someone in a .rar file? If so, ok. Personally, I wouldn't. Seems like Polly needed something to be as pure as could be digitally.

Well, that may be, but the answer to her original question is still technically "no".

but that is because you do not understand what occurs during rar/zip compression.

Well, I understand this, but I also understood (although maybe incorrectly) that compression/decompression was not perfect. A quick search on the innernets resulted in this, which was what my undestanding was before we started this debate:



But admittedly, that does not mean that an algorithm cannot compress a certain specific data stream losslessly, which is maybe what ZIP and RAR do.

Well I'm not sure where you got this on "the innernets" but the context of his/her discussion is probably relevant- either that, or he/she is wrong.

Smoke some pot, put on some rekkids and then zip and unzip a file 1000x and see if any of them are any different.

If it's digital, you already lost out.

Amusing thread to read. f4df is right. You can usefully compress WAV files with zip, rar, etc. without any degradation in quality because WAV is an uncompressed format (i.e. some WAV files contain a lot of "space") and those are lossless compression algorithms.

Thanks.

I also didn't understand what goes on during compression, so thanks for explaining that.

I'm still going to record to tape only.

I would encourage all musicians to do the same, it sounds phenomenally better.

Good explanation. Lempel & Ziv would approve.