CD-XA Disc Formats
The CD-XA media driver provides access to devices that support CD-ROM/XA discs. CD-XA (Compact Disc-Extended Architecture) refers to a storage format that accommodates interleaved storage of audio, video and standard file system data. CD-XA data is stored in a file system format on the discs, and playback control is managed by the CD-XA media device in cooperation with the amplifier-mixer device.
CD-XA takes advantage of a special ADPCM audio compression mechanism that not only yields a low data rate but also enables more audio data to be stored on a disc than that allowed by a CD-DA disc. ADPCM (Adaptive Delta Pulse Code Modulation) is an audio compression technique that allows up to a 16 to 1 compression of audio data.
By compressing the audio data (in some cases to 1/16 the size of CD-DA data) it now becomes possible to record multiple audio tracks on a single disc. With CD-XA level C, recorded in stereo, it is possible to interleave 8 different audio tracks on a single disc. With CD-XA level C, recorded in mono, this number climbs to 16 different tracks on a single disc.
The following table summarizes the different compression levels available with CD-XA and compares them to CD-DA.
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