KVR Audio

tracer_221 · Post by **tracer_221** » Fri Jul 08, 2005 4:21 pm

I was wondering if anyone has noticed the phenomenon that sometimes accurs with .rar archives. I had noticed heaps over the years of collecting sounds, but only just then did I realise what was happening, soughta. Sometimes when I have a sample that was, let's say '.rared', sometimes by unraring it, the content actually changes, like, the pitch is slightly in/decreased, or the sound has more/less harmonic content. It's quite bizzare, and sometimes a very noticeable thing. It can also be quite annoying, I've had old multisample sets of finely tuned intruments, that I've had to move from an old computer to a new one, and without the option of networking, I rared a lot of sets, and now the tuning is really screwed up. I was wondering if anyone else has noticed this? It's not that common, but common enough for it to annoy me... Or is it my imagination do you think?... Is it possible?

*EDIT*
I just did comparisons of several files using a pregram i was just informed of (in this thread, thanx)
http://www.scootersoftware.com/
and found quite a lot of differances within files that had been compressed and then decompressed. So like I say, maybe be careful with well tuned sample sets etc.

dougsyo · Post by **dougsyo** » Fri Jul 08, 2005 4:26 pm

If that happens, then the input file to RAR is not identical to the output. That would be a bug.

If you can document this - ie RAR a file, rename it, extract it, and compare the two - then it should be reported.

Otherwise I would view it as imagination.

Doug

tracer_221 · Post by **tracer_221** » Fri Jul 08, 2005 4:45 pm

Here is an example

(sorri, no example)

AndrewW · Post by **AndrewW** » Fri Jul 08, 2005 4:45 pm

From my experience .wav files when put into RAR file are hardly compressed, if any. The only this is that instead of many files you end up with one. And that's why anyone would want to use any kind of compression fomat.
If you use OSQ format from Wavelab, than it does compress WAV files up to 50% with no data degregation. There are others as well, but I don't know what they're called.
Take care

Meffy · Post by **Meffy** » Fri Jul 08, 2005 4:59 pm

I don't have WinRAR, so this might be off the wall... but here goes: Does it have a "lossy compression" option? Seems unlikely that this could be the cause of any problem -- I'd expect any compression losses (or, for that matter, any change at all) to result in a mangled, unreadable file.

Aldo · Post by **Aldo** » Fri Jul 08, 2005 5:05 pm

Meffy wrote:I don't have WinRAR, so this might be off the wall... but here goes: Does it have a "lossy compression" option? Seems unlikely that this could be the cause of any problem -- I'd expect any compression losses (or, for that matter, any change at all) to result in a mangled, unreadable file.

It doesn't.
It has a "multimedia compression" algorithm, lossless but quite effective on wave files. Much better than Zip BTW.

Aldo.

tracer_221 · Post by **tracer_221** » Fri Jul 08, 2005 5:09 pm

I reported the bug to winrar, after showing every one in my house the files, I came to the conclusion that there is a 90% chance it's not my imagination, lol. and now my family thinks I'm loosing it ('OI, is there a differance between this and this... BLEEP... BLEEEP')

blakes · Post by **blakes** » Fri Jul 08, 2005 5:10 pm

your sitting in front of pc man! everything is digital! theres only 0 and 1. so i'd say it's imagination

griels · Post by **griels** » Fri Jul 08, 2005 5:12 pm

Did you actually do a bitwise comparison on both files? Try Beyond Compare for this purpose.

tracer_221 · Post by **tracer_221** » Fri Jul 08, 2005 5:13 pm

blakes wrote:your sitting in front of pc man! everything is digital! theres only 0 and 1. so i'd say it's imagination

Yes, but when a file is compressed, it is changed (to be smaller), and in theory, it is changed back when you decompress it, but I guess winrar kinda makes mistakes when decompressing wave files.

griels · Post by **griels** » Fri Jul 08, 2005 5:16 pm

deema wrote:I guess winrar kinda makes mistakes when decompressing wave files.

Stop guessing and check with the aforementioned app!

Spe3D · Post by **Spe3D** » Fri Jul 08, 2005 5:19 pm

I noticed a lot of problems with the later versions of win rar – it came to my attention that files don’t recompile on lots of different computers after upgrading to a later version of winrar – so I stopped using it – I had not noticed sound differences just general corruption of the files – though it would not surprise me to find sound differences with the later versions of winrar.

The winzip aspects seem to be ok though for some reason.

Best regards,

Spe3d

:O)

tracer_221 · Post by **tracer_221** » Fri Jul 08, 2005 5:20 pm

griels wrote:
deema wrote:I guess winrar kinda makes mistakes when decompressing wave files.
Stop guessing and check with the aforementioned app!

I just did... and even files that I couldn't really hear a differance in, had slight differances.

griels · Post by **griels** » Fri Jul 08, 2005 5:21 pm

Curious... Thanks for the heads up

Probably best to use FLAC or Monkeys Audio for audio compression for now then

Meffy · Post by **Meffy** » Fri Jul 08, 2005 5:26 pm

Aldo: Oh -- thanks! I use Stuffit for reading RAR files, but don't make RARs for my own use so haven't messed with the format.

If a bitwise comparison shows things come out different than they go in, that sounds like a bug to me. "Lossless" has to mean completely lossless, not "pretty close." In an executable file, one flipped bit could bring the system down... or worse.

.rar Screws With Your Samples?