Specifications
CD-i FAQ 2000 Edition Revised February 21, 2001
Latest version and more CD-i info: http://www.icdia.org
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3.13.1 What is the screen resolution of a CD-i player?
CD-i can display both main planes in either normal, double or high resolution, which are 384x280,
768x280 and 768x560 respectively. Some encoding techniques are limited to a single resolution,
for example a DYUV image is always standard resolution. It is possible for the images on each of
the planes to be displayed at once, even if they are in different resolutions. For example double
resolution CLUT4 menu bar can be overlayed on a standard resolution DYUV image.
CD-i highest resolution (768x560), used for QHY images, is the highest resolution that can be
made visible on a normal TV set, so CD-i takes TV-technology to its edges.
3.13.2 Does CD-i make a difference between PAL and NTSC?
A CD-i consumer player is usually suitable for a dedicated TV standard, such as PAL or NTSC.
Some professional players have a switch at the backpanel to select the appropriate TV standard.
A CD-i disc is TV-standard independent: any CD-i disc can be played on any CD-i player where-
ever in the world. But due to the characteristics of both TV systems, special care has to be taken
into account when designing a CD-i title. An NTSC-display usually displays slightly less lines, with
slightly less pixels on each line. Usually the NTSC display is 720x480, compared to 768x560 for
PAL. When a full resolution image is displayed on an NTSC-display, the most outersized pixels
will drop out of the picture. When an NTSC picture is displayed on a PAL screen, very small black
bars are shown at the bottom and top of the screen (these bars are really small and should not be
compared to the black bars of a letterboxed movie). For this, the 'safety area' is defined, the size
of an image that is expected to be correctly displayed on all TV-sets. This safety area is 640x420,
no 'critical' information such as menu buttons should be displayed outside this area.
The same limitations with respect to the safety area apply today to DVD-Video titles that are to be
distributed world-wide.
3.13.3 Does CD-i support wide screen (16:9) TV sets?
Yes, any CD-i title can be viewed on a wide screen TV set using either one of the options offered
by the TV itself. No special resolutions adapted to the 16:9 aspect ratio are defined for CD-i,
however a picture can be 'squeezed' within a normal 4:3 image that can be 'de-squeezed' at
runtime by the TV-set.
Please be aware of the fact that, in contrast to any DVD-Video player, a CD-i player has no build
in facility to correct the display of a widescreen image on a normal 4:3 display by filling the screen
with black bars at the top and bottom. When a widescreen title is also to be used on a 4:3 display,
the content should also be stored in this aspect ratio on the disc.
Some consumer CD-i players (like the Philips CDI-220/60 and up) provide for a 16:9 switch in the
player shell. This switch records the setting in the CSD (See: 3.10 What is the CSD?), which
allows for applications to look for the connected TV format. When such a player is set in 16:9
mode, the player's startup shell is displayed in wide screen, but when a CD-i is started, the
screen is switched to 4:3 mode. An application that interpretes the aspect ratio setting in the CSD
may then turn the screen back to 16:9. This CSD entry is an extension that is not specified by the
Green Book, and there are only a few applications that supported it.
3.13.4 How does CD-i Full Motion Video work?
When the term FMV, or Full Motion Video is used, it often refers to the display of MPEG Digital
Video. Altough a CD-i player is capable of various full screen animation options and partial screen
motion video, it can be extended with a Digital Video cartridge. In some players, this Digital Video
cartridge is already built-in. Digital Video is considered a must-have extension to CD-i, and is
described as an option in chapter 9 of the Green Book.