Files
Unlike on a DVD or CD-ROM, there are no "files" on a Red Book audio CD; there are only the physical pits and lands, which in turn represent a single encoded data stream, which ultimately represents one continuous stream of LPCM audio data, and a parallel, smaller set of 8 subcode data streams. Computer operating systems, however, may provide access to an audio CD as if it contains files. For example, Windows represents the CD's TOC as a set of Compact Disc Audio track (CDA) files, each file containing indexing information, not audio data.
In a process called ripping, Digital Audio Extraction software can be used to read Red Book audio data and store it in files. Common audio file formats for this purpose include WAV and AIFF, which simply preface the LPCM data with a short header; FLAC, ALAC, and Windows Media Lossless, which compress the LPCM data in ways that conserve space yet allow it to be restored without any changes; and various lossy, perceptual coding formats like MP3 and AAC, which modify and compress the audio data in ways that irreversibly change the audio, but that exploit features of human hearing to make the changes difficult to discern.
Read more about this topic: Session (CD)
Famous quotes containing the word files:
“The good husband finds method as efficient in the packing of fire-wood in a shed, or in the harvesting of fruits in the cellar, as in Peninsular campaigns or the files of the Department of State.”
—Ralph Waldo Emerson (1803–1882)
“But some who this blithe mood present,
As on in lightsome files they fare,
Shall die experienced ere three days be spent—
Perish, enlightened by the vollied glare;
Or shame survive, and, like to adamant,
Thy after shock, Manassas, share.”
—Herman Melville (1819–1891)
“Here files of pins extend their shining rows,
Puffs, powders, patches, bibles, billet-doux.”
—Alexander Pope (1688–1744)