CD-ROM XA Format
CD-ROM XA (for eXtended Architecture) discs contain Mode 2 sectors and were designed to allow audio and other data to be interleaved and read simultanously. This avoids the need to load images first and then play CD audio tracks.

The CD-ROM XA specification also defines certain image and audio formats to use:

• The graphics formats include 256 color modes which are compatible with PC formats and CD-i.
  
• The audio used is ADPCM (Adaptive Delta Pulse Code Modulation) which is also defined for CD-i.
  

This CD-ROM XA format has not been successful in itself but there are three important formats based on it: Photo CD, Video CD and CD EXTRA. CD-i also uses mode 2 sectors and shares some commonality with CD-ROM XA for example both use ADPCM audio.

- posted by J @ 5:54 AM