1 : CD-G
2 : External links
A CD+G is a special Audio Compact disc that contains graphics data in addition to the audio data on the disc.
The disc can be played on a regular Audio CD player, but when played on a special CD+G player, can output a graphics signal (typically, the CD+G player is hooked up to a television set).
In each sector there are 2352 bytes (24 - 98) of Audio Content data and 96 bytes of Subchannel data.
The 96 bytes of Subchannel information in each sector contain 4 packets of 24
bytes apiece :
1 byte for command,
1 byte for instruction,
2 bytes for parityQ,
16 bytes for data, and
4 bytes parityP.
Each byte in the 16 byte data field can be thought of as being divided
into 8 bits. Each of these bits corresponds to a separate stream of information. These streams are called "channels", and are labeled starting with the letter P, like so:
{| cellpadding=3
|-
|Channel
|P
|Q
|R
|S
|T
|U
|V
|W
|-
|Bit
|7
|6
|5
|4
|3
|2
|1
|0
|}
Both the P and Q channels, on a regular Audio CD are used for timing information.
They are used to assist the CD Player in tracking the current location on the
disc, and to provide the timing information for the time display on the CD
Player.
The CD+G format takes advantage of the channels R thru W, which are unused in standard audio CD formats. These six bits are used to store graphics information.
In the CD+G system, 16 color graphics are displayed on a raster field which is
300 x 216 pixels in size.
External links
|