[wovenhand]

I'm on mac so I don't have a dedicated program for zip'ing stuff (though it's available out there), but anyway, can zip compress lossless?

The reason I'm asking is that I just purchased an album online in wav format (24-bit) and I asked the label beforehand how it was going to be delivered, and he said "one big zip, compressed lossless", though after download & unpack I see that the zip file is 430MB, and the actual files when decompressed are 640MB.

The reason for me buying this in the first place is because of the higher bit depth (since I already own the CD), so if it's been compromised when bundled into a zip I'm gonna demand a refund.
My ears are way too tired to do any A/B'ing now (it's 2:15am), so I can't really say I'm hearing any artifacting due to compression.

 

[Alleyman]

Zip and other popular archiving formats for that matter are lossless, so your purchase is safe.

 

[mofonyx]

It can't if* you're Patrick82

Otherwise, it should be fine. Unarchiving it from zip should be the same lossless files as before zip compression.

 

[Tabi]

Data compression formats are always lossless.

 

[HFat]

I would have thought that you can't compress lossless (not that much anyway) although I've never looked into the issue. That's odd... are you sure the decompressed files are compressed?

In any case, I don't think there's such a thing as lossy "ZIP" compression (regular "ZIP" compressions is definitely lossless) so I wouldn't worry about that.

Something else is odd... a 24-bit album taking only 430M? There are redbook CDs that you can't compress to that size! I've got a fairly clean-sounding 5 min. song in 24/96 around that weighs 95M.
It's certainly theoretically possible to compress a 24-bit recording that much but I guess you wouldn't lose much by converting it to 16-bit in that case. But what do I know?

 

[wovenhand]

The sample rate is just 44.1kHz so a 2 minute song is approx 30MB in size.

Thanks for the info!

 

[spongezone]

You can compress .wav. You shouldn't be able to make something like FLAC more than a few percent smaller. Either way, all archivers are by definition lossless, otherwise they would be worthless.

 

[Redo]

Quote:

Originally Posted by spongezone /img/forum/go_quote.gif You can compress .wav. You shouldn't be able to make something like FLAC more than a few percent smaller. Either way, all archivers are by definition lossless, otherwise they would be worthless.

You won't be able to make FLAC files any smaller. FLAC and other audio lossless compression for music bests all traditional file compression formats (zip, rar, 7z, ace, etc). In fact, zipping a FLAC file should result in a slightly greater filesize, due to the headers and whatnot.

 

[HFat]

Quote:

Originally Posted by wovenhand /img/forum/go_quote.gif The sample rate is just 44.1kHz so a 2 minute song is approx 30MB in size.

So that's simply a short album.

I'd wager these are PCM files and not lossless files. 24/44 PCM weighs about 15M per minute. This is why these files can be compressed.

 

[003]

Umm, if you own the CD, how do you expect these files to be better than the CD, when the CD is as good as it gets? They can be the same as the CD, but not better, unless they are SACD rips or something of the like.

 

[justin2net]

lossless audio compression=analysis of audio (waves), then compresses it.

"lossless" data compression=analysis of bits and bytes and similarities, then compreses it.

 

[balou]

Quote:

Originally Posted by spongezone /img/forum/go_quote.gif Either way, all archivers are by definition lossless, otherwise they would be worthless.

Sorry, but this is completely bogus.
There are lossy archivers, which omit information and make a file always smaller.
And there are lossless archivers/archive formats. The most known example is Zip.
As the name implies, Zip files are NOT lossy. No file loses even the tiniest bit of information.
But, the point is: Zip files don't make every file smaller. Your favorite collection of white noises, for example, will most likely expand in size. But most sound recordings, namely the ones we call "music", have some inner structure. Compress a sine wave with zip, and you will achieve impressive compression results - because it's far away from noise, and can thus be easily 'described' in a zip file.

This was quite a simple explanation of lossless data compression - if somebody is interested, I can describe the workings of the zip algorithm much more in depth

 

[fordgtlover]

What would be an example of a lossy archive format?

The only style I can think of are lossy conversions formats such as MP3, but there is never an expectation (or shouldn't be) that if required the original can be reliably recreated from the lossy format. So they're not really archive formats as such.

 

[wovenhand]

Quote:

Originally Posted by 003 /img/forum/go_quote.gif Umm, if you own the CD, how do you expect these files to be better than the CD, when the CD is as good as it gets? They can be the same as the CD, but not better, unless they are SACD rips or something of the like.

CD (16-bit): 96dB S/N
These wav's (24-bit): 144dB S/N

 

[wovenhand]

Quote:

Originally Posted by HFat /img/forum/go_quote.gif So that's simply a short album. I'd wager these are PCM files and not lossless files. 24/44 PCM weighs about 15M per minute. This is why these files can be compressed.

Yeah, they're PCM and not a lossless format like FLAC.
And yes, it's a relatively short album. Short and sweet.