FLAC Joins The Xiph Family

Ancipital writes "Xiph.org (of Ogg Vorbis fame) have today announced that the FLAC (Free Lossless Audio Codec) project has joined the Xiph rebel alliance. The full story and press release can be found at the Xiph site. (FLAC is nice, because it gives you pristine lossless audio at roughtly 50% size reduction over uncompressed WAVs- you can store them on your hard drive/wherever and then transcode down to a lossy format when you need portability, yum!)"

Comments

Re:Algorithms?

[Josh Coalson]

So what sort of compression algorithm does FLAC use?

• interchannel decorrelation: mid-side coding
• intrachannel decorrelation: FIR linear prediction
• entropy coding: Rice codes with a simple context mechanism

For more info see here

One idea that would be really cool is if they could get acheive lossless compression by noting the differences between the original and the .OGG, and appending that to the .OGG. Then if you can just strip off the added info when you make copies to restricted-space devices. The only question is whether this can be done with a competitive compression ratio.

This has been suggested before, but would require all Vorbis decoders to decode to the exact same result, which is not practical (Vorbis decodes to float samples).