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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7. CD-i Authoring
7.1 How is CD-i authoring generally done?
CD-i authoring involves several steps, most of which should be followed in order, some of which
can be done at the same time. Generally, one starts with the design phase. The producer of a
disc decides what it should be all about, how the interactivity will take place, what screens the
user will see, what audio will be used, etcetera. Then, the assets (audio and video material) will
be created. These are usually made using regular video and audio editing software, and then
converted into CD-i's audio and video formats. Now, the program code should be written, or -in
case a high-level authoring tool is being used- the assets should be placed in their correct order.
The program code or scripts then need to be converted to CD-i's real time disc format, this
process is usually called disc building (see: 7.2 What is disc building?). This disc building then
results in a disc image which can be played back using an Emulator (see: 7.4 What is a CD-i
Emulator?), burned onto a CD-Recordable or sent to a manufacturing plant for replication.
7.2 What is disc building?
A critical step in the development of a CD-i title is the so-called disc building process. Because of
the fact that CD-i almost entirely depends on its real time behaviour (see: 3.4 What is a real-time
system? in section 3 of this FAQ), it is very important that the audio and video are placed in the
correct way on the disc. Unlike other non-realtime systems like PCs with a CD-ROM drive which
can store large amounts of audio and video data in memory for later playback (and hence
requiring more complicated and expensive systems), a CD-i player reproduces the audio and
video data in realtime when it is being read from the disc. To accomplish the seamingly similar
retreival of audio and video at the same time, CD-i uses a clever sector format (see What is
sector interleaving? in section 3 of this FAQ).
Naturally, this process of placing all the information bits at the correct order is not done manually
(although it remains the CD-i producer's responsibility to investigate wether the choice on amount
and quality of audio and video will fit in the data stream). The process of the creation of a file that
represents the contents of a CD-i disc is called disc building. The resulting file is usually called a
CD-i Disc Image. The Disc Image can be played back using an Emulator (see: 7.4 What is a CD-i
Emulator?) or burned on a CD-R to check wether its behaviour on an actual CD-i player is as
expected.
7.3 What is a CD-i authoring or development player?
A CD-i authoring player is a CD-i player that can play CD-i discs in a normal way, but which has
some extensive features especially added for CD-i authoring studios. An authoring player can for
example be connected to an Emulator (see: 7.4 What is a CD-i Emulator?) for the retreival of data
as if it was being read from a CD. Furthermore, an authoring player provides for a SCSI-port to
connect SCSI devices like harddisks and a CD-Recorder and a coaxial ethernet connector to
hook it up in a local network.
There were two different models of CD-i authoring players from Philips. The first model was the
CDI 180/181/182 modular CD-i system (which was also the first CD-i system ever released). The
CDI-182 Expansion Module added the authoring facilities (the SCSI port, the ethernet port, a
parallel port and 1 MB of extra RAM) to the generic system. Later, the CDI 605/00 replaced this
system as an all-in-one authoring player. The CDI 605 consisted of 5 MB of RAM, ethernet, SCSI,
parallel, extra serial ports and several diagnostic and emulation tools build in ROM. Since both of
these players could not be expanded with a Digital Video cartridge, a new version of the CDI 605
was released as CDI 605T/20 which provided space for a Digital Video extension.