Free Lossless Audio Codec Support Implemented
FLAC files sound as good as WAV, but are half the size.
Sunday, August 19, 2007
I resumed work on Ogg Frog a few days ago after a pause of several months. Things had been just too unsettled in my life to focus on Free Software development - I got a new job, and moved from Vancouver, British Columbia to California's Silicon Valley. But I'm happy to report that I have added support for the Free Lossless Audio Codec (FLAC) to Ogg Frog.
The advantage of FLAC is that one can use it to make bit-for-bit perfect backups of of audio compact discs while storing the data in a minimum of disc space. The more-familiar WAV format is also CD-quality, but FLAC files are about half the size of WAVs.
While Ogg Vorbis and MP3 files compress to a much smaller size than FLAC, they do so at the cost of some audio fidelity, because they use "lossy" compression methods such as psychoacoustic modeling to eliminate data from the audio signal that humans don't hear well; however, it is possible to hear the difference, especially when the compression is more extreme.
Another advantage of FLAC files is that it one can embed cuesheets in them rather than having to store the cuesheets as separate files as is the case when they are used with WAV or BIN backups. Cuesheets, among other things, record the precise start and stop points of each track on an audio compact disc.
When used with CD burning software that supports cuesheets, one can burn a duplicate of a CD from a single file that has the same tracks as the original. When the duplicate CD is played by a player that can look up the album at a CDDB service like FreeDB, the correct album title, artists and track titles can be retrieved. This isn't the case with audio software that doesn't support cuesheets, such as iTunes; while iTunes will keep the track titles in its database on the computer that a duplicate CD was burned on, iTunes users are frustrated to find that the titles are not retrieved when the CD is played on a different computer, or worse, that the titles for a completely different album are found.
It is also possible for audio players to use cuesheets to access the individual tracks of single-file compact disc backups. That is, if one rips a CD to a single FLAC file while embedding a cuesheet in it, a player can list each individual track in its playlist just as it appeared on the original CD. One can then make new playlists combining tracks from different FLAC backups just as if they were stored as separate files.
This was identified as a strategic feature for FLAC players on the FLAC mailing list, and will be available in Ogg Frog when version 1.0 ships. In fact I plan to start work on implementing it later tonight, after I post this blog entry.
(Ogg Frog 1.0 will just be a player, decoder and cuesheet splitter; it won't support ripping yet - that will be in version 1.1 - nor will it support burning - that's planned for 1.2.)
Well, time to get back to work!
-- Rippit the Ogg Frog, rippit@oggfrog.com
What the Bold Print Giveth, the Fine Print Taketh Away
Copyright © 2006 Michael D. Crawford.
Ogg Frog, Rippit, Rippit the Ogg Frog, the Frog logo and the Circle Flowers logo are trademarks of Michael D. Crawford. All other trademarks are the property of their respective owners.
So there.