CD Archiving 2: Flac Racket

Posted on | September 12, 2009 at 9:59 am | 1 Comment

In part 1 of this series, I posed the question of what to do about archiving my CD collection to my PC if I wasn’t going to use the MP3 format? That wasn’t strictly the right question, since my desired target solution still involved MP3s as part of the equation. There’s two issues really: listening and archiving. For listening, it’s still easiest to use MP3s files, because they’re small and portable and are easily transferable to the iPod. But they don’t resemble the source material closely enough. So when ripping my collection for archival purposes, I still wanted to be able to produce both MP3s and something more… real.

The most accurate representation of a CD as stored on a file on the computer is traditionally the WAV format. But those take up so much space, that even with the cheapness of hard drives these days, we’re still talking a heckuva lot of moolah for a drive big enough to hold my entire collection. Plus, WAV files are so unwieldy.

I’d heard of FLAC (Free Lossless Audio Codec) for awhile, and have even downloaded some songs in that format. Since it’s a lossless compression scheme, it preserves all the original data from the CD. MP3 is lossy compression scheme, so it’s essentially throwing away part of the data. The lower the encoding bit rate, the more it throws away, and less like the original recording it sounds. Even at higher bit rates, I can sometimes hear compression artifacts on MP3 files, like the flanging effect it adds to cymbals, which drives me crazy.

Besides the space savings (a typical FLAC file will be around 60% of the size of the corresponding WAV file), the FLAC format has other advantages over WAV as well. You can embed metadata into the FLAC file, which is kind of like tags in an MP3 file. You can identify the artist and album name, etc. I make one FLAC file for an entire album, and it has the cuesheet embedded into it. The cuesheet contains the list of songs on the album and where they start and stop. That can be used to play individual songs from the file on players that support FLAC and cuesheets (such as foobar2000), and it can also be used to split out the FLAC file into individual track FLAC or MP3 or other files, and to write the FLAC archive back to a CD-R, replicating the original CD exactly. The cover art can also be embedded into the file, as well as “ReplayGain” information, which tells ReplayGain-equipped players to play the album at a lower or higher relative volume level than it was written with. I’ve really just scratched the surface here, there’s more you can do with FLAC files.

One thing that is confusing about FLAC is that there is a compression level parameter consisting of 0-8 levels. I wondered why there are different compression levels if FLAC is a lossless compression scheme? Wouldn’t the resulting file always be the same? It turns out that the compression level affects the speed of encoding and also the resulting size of the file, but does not actually affect the sound quality. Regardless of the compression level, all of the original data is still there on decoding, and decoding speed is always fast regardless of the encoding compression level. Yeah, it doesn’t make much intuitive sense, but just go with it. So level 0 is the fastest compression with the largest file size, and 8 is the slowest compression with the smallest file size. Level 5 is the default. I’ve found that the file sizes aren’t dramatically reduced by a higher compression level, so I just stick with the default.

Keep in mind I’m not a sound engineer or compression expert, so take everything I say with a healthy dose of skepticism…

Anyway, my goal became to produce a single FLAC archive for every CD, and also MP3 files of every track that I could import into iTunes. Sounds like a hassle? Not really. Actually, it’s pretty easy.

But I’ll get to that
Latre.

Pet Peeve of the Day: Why is it impossible to get an intact Butterfinger fun size bar and not one that’s crumbled into pieces?