FLAC (Free Lossless Audio Codec) preserves every bit of the source audio. The “bit depth” refers to dynamic range (the difference between the loudest and quietest sound):
"Toxicity" the song played next. The banjo riff, warped and frantic. Serj singing about "eating seeds as a pastime activity." And then the chorus: "They're trying to build a prison / For you and me to live in."
The benchmark against which all others are measured. It's clean, clear, and widely available. However, its 16-bit depth can be a limitation on a high-end sound system, and the master used for some CD pressings may be a victim of the "Loudness War," with dynamic compression applied to make it sound louder on the radio.