How Does A Lossless Codec Work/Choosing the Right One?

WaWaZat -- Fri, 07/11/2008 - 00:15

How does a format like Apple Lossless and FLAC compress file size without compromising audio playback quality in any way? What do these formats take out so as to make the file smaller? Or is a lossless format basically encoding during a rip, then decoding (much like a Dolby noise reduction operates) on playback to reveal the audio in it's full resolution??? Have there been any published listening tests, by reliable sources, between CD audio - lossless - or even uncompressed WAV/AIFF's? Are these all truly sonically identical? Also, are all lossless formats created equal when it comes to sonics & metadata support? FLAC has an advantage of being nonproprietary so this might be a more wise choice, for instance, when archiving one's collection of CD's that may total in to the thousands. I've heard however that FLAC may store limited metadata info. Bottom line here; what would be the wisest format for an audiophile to rip large collections of CD's to when putting together a music server? Any info and enlightenments are greatly appreciated!

Steven Stone -- Fri, 07/11/2008 - 09:28

I would humbly submit that most of your questions can be answered on-line by the judicious use of Google's search engine.

Numerous FAQ's already exist on the subjects of Lossless compression and audio quality as well as the how's and why's of the process.

Cliff notes version answers (because I'm on deadline for multiple publications right now)

Lossless compression throws out no useful data - that's why it's called lossless.

I can't speak for all listeners, but personally I haven't heard any audible differences between Apple Lossless files and wave files played back via iTunes. YMMV.

FLAC is a more universal and open codec, but has quite a few different implementations that can and do sound differently, at least according to the chatter I've read on the subject. I don't care much because I use Apple Lossless, iTunes, iPods and devices that are compatible with these systems, which FLAC is not. FLAC is far too DIY for my tastes.

Bottom line if space, time, and money (as it translates into disc space and rip time) aren't a consideration rip all files in WAV. The only disadvantage is the lack of iTunes compatible-managable meta files and inability to bring in cover art (For some reason known only to Apple software engineers iTunes locks WAV files from receiving new cover art.) Also via iTunes you can make duplicates of WAVE files in Apple lossless and do all your metafile and cover art manipulations on the Apple lossless versions (that is what I do)

Steven Stone
Contributor to The Absolute Sound, EnjoytheMusic.com, Vintage Guitar Magazine, and other fine publications

omas@seneschal.net -- Thu, 02/19/2009 - 14:48

 Hey WaWaZat,
I wrote several articles for pro audio magazines that discuss lossless coding...Take a look at an overview piece, <www.seneschal.net/papers/bitstream/bstream050.htm>. If you're interested, MLP is a special case that's covered in <www.seneschal.net/papers/mlp.htm>.
If you're a Win kinda guy, I'd stick w/FLAC. If you're a Mac kinda guy, it's a tossup. FLAC is more interoperable but Apple Lossless is better supported on that platform.

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 Oliver Masciarotte

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