Optical disc recording modes

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Optical disc authoring
Optical disc Optical disc image Recorder hardware Authoring software Recording technologies Recording modes Packet writing
Optical media types
Laserdisc Compact Disc/CD-ROM: CD-R, CD-RW DVD: DVD-R, DVD-R DL, DVD+R, DVD+R DL, DVD-RW, DVD+RW, DVD+RW DL, DVD-RAM Blu-ray Disc: BD-R, BD-RE HD DVD: HD DVD-R
Standards
Rainbow Books File systems ISO 9660 Joliet Rock Ridge Amiga extensions to Rock Ridge El Torito Apple ISO9660 Extensions Universal Disk Format Mount Rainier

In optical disc authoring, there are multiple modes for recording: Disc-At-Once and Track-At-Once.

[edit] CD Disc-At-Once

Disc-At-Once or DAO for CD-R media is a mode that masters the disc contents in one pass, rather than a track at a time as in Track At Once. DAO mode, unlike TAO mode, allows any amount of audio data (or no data at all) to be written in the "pre-gaps" between tracks.

One use of this technique, for example, is to burn track introductions to be played before each track starts. A CD player will generally display a negative time offset counting up to the next track when such pre-gap introductions play. Pre-gap audio before the first track of the CD makes it possible to burn an unnumbered, "hidden" audio track. This track can only be accessed by "rewinding" from the start of the first track, backwards into the pre-gap audio.

DAO recording is also the only way to write data to the unused R-W sub-channels. This allows for extended graphic and text features on an audio CD such as CD+G and CD Text.

[edit] CD Track-At-Once

Track-At-Once or TAO is a recording mode where the recording laser stops after each track is finished and two run-out blocks are written. One link block and four run-in blocks are written when the next track is recorded. TAO discs can have both data and audio at the same time.

[edit] DVD-R Disc At Once

Disc At Once recording for DVD-R media is a mode in which all data is written sequentially to the disc in one uninterrupted recording session. The on-disk contents result in a lead-in area, followed by the data, and closed by a lead-out area. The data is addressable in sectors of 2048 bytes each, with the first sector address being zero. There are no run-out blocks as in CD-R disc-at-once.