After the astounding response from my article on Ogg Vorbis What the hell is Ogg Vorbis, and why should I use it?, I thought it would be nice to do a follow up article on another open source audio format called FLAC.
So, what is FLAC? FLAC is an acronym that stands for Free Lossless Audio Codec. Flac is completely non-proprietary and free of licensing fees, unlike mp3. Flac is also much higher quality than mp3 or Ogg. This format compresses the data without having to dispense of any data.
Essentially, when you rip your cd's to FLAC format, you have an exact digital copy.
I took a CD and used Sound Juicer (opens automatically in Ubuntu when you insert an audio cd) to rip the music to my hard drive in two formats: CD quality Ogg (default) and FLAC. The difference in size is AMAZING.
Album ripped to Ogg - 48.2MB
Album ripped to FLAC - 292.9MB
And, for a song for song comparison...
Song ripped to Ogg - 4.6MB
Song ripped to FLAC - 28.5MB
Wow, I never expected to see that huge of a difference in file size. If I was to have my trivial music collection in FLAC format, it would require at least 60GB, compared to the 10GB required for Ogg. Hard drives are getting larger and cheaper, but that's still a lot of storage space for a relatively small amount of music. There must be a huge difference in the audible quality then, right?
I very un-scientifically listened to multiple songs, first in Ogg, then in FLAC, to see if I could distinguish a difference. Surprisingly, I heard almost no difference at all. In some songs, the FLAC format sounded a little more full than Ogg, but I really had to strain to hear the difference. Although, I am using pretty regular speakers, and soundcard, and I'm by far not a sound expert. I'm just the average user, as far as music goes.
For the average user, it seems much better to stick with the Ogg format for audio. The small difference in audio quality, and huge difference in file size just wouldn't justify switching to FLAC, for most people.
So, when would you want to use FLAC? If you want to make an exact digital backup of your whole music collection, FLAC would be a good way to go (space permitting). If you have an incredibly loud, crisp, clear sound system that can piss off your neighbors two houses away, you'll probably be able to hear a difference as well. Or, if you're an audio aficionado, you'll probably be picky enough about how your music sounds to shell out the extra money for hard drive space so you can listen to everything in great detail. FLAC is also very well supported across OS's Linux, MAC, and Windows. There are also quite a few home theater devices that support FLAC.http://flac.sourceforge.net/links.html#hardware
I'm not aware of any portable devices that support FLAC, and with size constraints I can see why. (please comment if you know of any) As a commentor pointed out, FLAC would aslo be useful if you're encoding to many different formats because it's more or less as if you're ripping directly from cd since it's lossless.
Impressive as FLAC is, I can't recommend it for the average user. There's just not enough difference in audio quality to justify the huge difference in storage space.