FLAC - Format overview

The FLAC format is a lossless audio compression method that maintains the original quality of the audio data. It consists of a basic structure with four identifying bytes, metadata blocks, and encoded audio frames. Metadata blocks can include information like sample rate, number of channels, and MD5 signature for error checking. The encoding process involves blocking the audio data, optionally applying inter-channel decorrelation, and using either fixed polynomial prediction or general linear predictive coding (LPC) to approximate the signal. The residual is then encoded using Rice codes tailored to the specific distribution of the residual signal. Finally, the audio frames are protected by sync codes, frame header CRCs, and block/sample numbers for error detection and seeking. FLAC also supports ID3v2 tag skipping and has a verify option for decoder output comparison during encoding.