MPEG-FAQ 4.1:

What's about Video-CD and CD-I ?

FAQ ABOUT VIDEO CD and CD-i
Copyright (c) 1996 Steve Perlman, Visible Light
Revised: 15 Mar 96

Introduction
The Different Formats of Video CD and CD-i
Special Considerations To Play Green Book
An Important Choice: Windows 3.1 or 95
Playback Software For Video CD and CD-i
Using Software Decoders

Introduction

Every day, I'm contacted by an increasing number of PC owners
who want to playback their CD-i and Video CDs on their PCs. The
answer to the question "Can I play Video CDs and CD-i on my PC?"
is absolutely and positively a "maybe!"

Without question, you must have an MPEG decoder to playback a
Video CD or CD-i. Software-only decoders, like CompCore SoftPEG,
are inexpensive and work well with fast Pentium based PCs. The 
hardware decoders, like Sigma Designs' REALMagic, are more costly
but will run well even on 486 PCs, since the processing is all 
done on the board.

But, just having an MPEG decoder just isn't enough! So beware! 
There are hardware, software, driver and configuration issues that
must be resolved to play Video CD or CD-i. The bright spot is that
it generally can be done!

This FAQ explains the factors involved in playback of Video CD and
CD-i. Hopefully, you're somewhat knowledgeable of your PC hardware
and configuration!



The Different Formats of Video CD and CD-i

Looking at the way Video CD and CD-i has evolved may arguably lead
one to believe that it was created to confuse the world on purpose.

Have you ever stopped to think about how many types of Video CD and 
CD-i there really are? There are at least four types! Each one has a
different format!

There is Green Book, White Book, CD-i Interactive and Video CD 2.0.
Wow! Which one you have will affect your ability to playback the CD
using Windows. So, let's start by unraveling the mystery behind the
formats of Video CD and CD-i. 

Don't let the term "book" confuse you. It's just a cute name given 
to that particular format. It's not difficult to identify which type
of CD you have!


GREEN BOOK
This is the earliest format created by Philips for CD-i movies. Most
of the Philips CDs dated 1993 and earlier are Green Book. Look on the
CD itself for the wording "Digital Video". You will also find that 
the directory is unreadable on a PC.

WHITE BOOK (Video CD 1.1)
This is the latest format used by Philips for CD-i movies. Most of
the Philips CDs dated 1994 and later are White Book. Look on the CD
itself for the wording "Video CD". You will find that this directory
is readable, and there are files with the extension .DAT

CD-i INTERACTIVE
This is the Philips format for games and other interactive content.
The CDs use wording like "CD-i Games" and "CD-i Interactive". These
CDs are not playable on a PC unless you have a very expensive board
which only Philips supplies.

VIDEO CD 2.0
The world wants to develop interactive content. But, it doesn't want
to pay high fees to Philips to develop CD-i Interactive disks, and
wants to have wide distribution on PCs. Thus, the new Video CD 2.0 
standard was created. It is an extension of Video CD 1.1, and has a
readable directory with .DAT files. These CDs should begin to receive
widespread distribution by the end of 1996.



Special Considerations To Play Green Book

Green Book is not entirely supported on PCs, because Green Book format
cannot be read as a standard ISO-9660 CD (meaning no readable directory).
Therefore, some CD drive manufacturers did not build Green Book format
support into their CD drive hardware. These CD drives cannot read Green
Book format. They must be replaced to play Green Book CDs.

Panasonic and Matsushita drives typically do not support Green Book.
Unfortunately, many of these drives were distributed by Creative Labs
with their multimedia upgrade packages. When selecting a drive, make
certain that it is "CD-i compatible". Most CD drives are.

The error most attributable to the CD-ROM hardware problem is the now
infamous MMSYSTEM001: External Error. This is a general catch-all error
which means that the CD-ROM drive is not responding properly. The most 
likely reason is that the drive simply can't read the disk.


That's not all!

Windows 3.1 CD drivers, using the file MSCDEX.EXE, supported Green Book
format. As long as the CD drive hardware could read Green Book, you can
playback a Green Book CD without problems. Windows 3.1 was such a nice,
friendly operating system.

Then came Windows 95, touted to us as being 100% compatible with Win 3.1.
Except for one thing! Microsoft didn't tell us that Green Book support
was removed from the Windows 95 CD drivers!

So, Green Book CDs are specifically not supported in Windows 95. 

That doesn't mean you won't be able to use Windows 95 to play Green Book 
in the future. But, Microsoft has to release a new driver or another fix
must be found. It is believed that you may be able to use the Windows 3.1
MSCDEX drivers, and disable the Windows 95 CD drivers. This is all being
tested now, so we will cover this point in a later revision to this FAQ.



An Important Choice: Windows 3.1 or 95

We covered the requirement for playback of Green Book CDs, that the 
Windows 3.1 CD driver (MSCDEX) be used instead of the Windows 95 driver.
But, there is also a special bug in Windows 95, for which Microsoft has 
not yet released a fix publically yet.

An IDE CDROM may not reside on the primary channel with you Hard Drive.
It must be on the secondary channel. If you have a 486 with no EIDE
(no secondary channel) and want to use an IDE CDROM, tough luck. If
you have a Pentium and an IDE CDROM, move it to the secondary channel.

In general, you will find Windows 3.1 to be the preferable environment
for playback of Video CD and CD-i. There are less things to go wrong,
and configuration problems are easier to control.

Windows 3.1 is a good test environment also. If you have problems with
playback of Video CD and CD-i under Windows 95, you should test first
under Windows 3.1 if possible. That will help you define whether or not
the problem is hardware (the CD drive) or Windows 95 itself. Unless you
have a hardware problem, you should always be able to play Video CD and
CD-i under Windows 3.1!

Direct Draw improves video considerably under Windows 95, and improves
the frame rate. Direct Draw drivers write YUV information directly to
a video card that supports it. Generally, these video drivers are not 
available yet, but some vendors have begun distribution of the beta 
versions of their Direct Draw drivers. Diamond has Direct Draw beta 
drivers available for its Video 2001 series. S3 reportedly has also 
released its beta version for public testing. A special warning though.
These beta versions are generally untested, and may generate unwanted 
or unexpected results during playback!



Playback Software For Video CD and CD-i

Media Player, distributed with Windows, will playback .MPEG and .DAT
files very nicely. But, you have to point to these files directly.
With Video CD and CD-i, you want software that will read the CD header
and begin automatic playback of the CD. Media Player does not support
this, and most of the players for the PC will not either.

Therefore, you must find a player that will support playback of Video
CD and CD-i. CompCore's SoftPEG 2.0 is distributed with CD Vision, a
player that supports Green Book, Video CD 1.1 and Video CD 2.0.

So, if you want to playback Video CD or CD-i, you need more than just
an MPEG decoder. You need one that has a driver and a player that will
support the playback of these formats!



Using Software Decoders

Software decoders will run fine with Video CD and CD-i, although there
are CPU constraints. Because these decoders use your CPU for processing,
frame rate is dependent upon the speed of your processor. Generally,
the decoder should be configured for maximum CPU usage (90%), and all
other applications should be closed.

Another factor is that Windows 3.1 is a bit faster than Windows 95 for
software decoding. Windows 95 tends to use more system resources. This
is a minor consideration, though, because the 32-bit decoder drivers 
talk nicely with the new graphics accelerator boards. In fact, the new
Direct Draw drivers will greatly improve things further.

Use of software decoders should be limited to Pentium platforms, for
best frame rate and better compatibility.