Authoring your disk

Authoring a disk

A Video-CD contains MPEG-1 video sequences which conform to the "White Book" standard that was created by Philips and JVC in 1993. The first track of a Video CD contains the CD-i play program, the CDI, MPEGAV and VCD directories based on the ISO 9660 file system. The next tracks are in the format CD-ROM/XA-Mode 2/Form 2 Sectors and contain the MPEG encoded audio/video sequences that are listed in MPEGAV.

Video-CDs can be played on CD-i players, some Video-CD players or on a PC based CD-ROM drives with CD-ROM/XA support and MPEG decoder software.

VideoCD supports the following formats:

352x288 with 25 frames a second (PAL)
352x288 with 29.97 frames a second (NTSC)
704x576 as single frame
704x480 as single frame
352x288 with 29.976 frames a second (Sometimes called "FILM" resolution)

For our tutorial we used Nero Burning but the process is similar with any CD authoring software.

We selected Video-CD from the New Compilation wizard and have checked the option to create a standard compliant CD...

We won't go through the detailed setting for Nero here since you might be using some other burning software. When the wizard closes we see a typical Windows explorer-like view in the right panel and the disk layout in the left. Because we're creating a Video CD Nero creates the folders CDI, EXT, MPEGAV, SEGMENT and VCD by default so all we have to do is drag our movie(s) onto the new disk image.

Nero is smart enough to recognize complaint source files. If we had dragged the wrong format onto the video space it would have displayed an error message.

VideoCD V2.0 (VCD) is a standard used to save audio/video data to a CD to be played back by CDI or DVD players. The audio/video data streams are compressed with MPEG-1, Audio Level 2 and played in real time at 75 blocks per second. Because this format and audio/video data generally tolerate bit errors, the space that is normally needed for error correction can be used for MPEG data instead which increases the amount of user data in a block from 2048 to 2324 bytes per block. This gives the VCD 13% more capacity compared with MPEG file storage on a data CD.

The Super VideoCD (SVCD) format is an extension of the VCD standard in which the MPEG-2 compression standard is used with variable bit rate coding which allows twice the bit rate of the VCD. As a result the SVCD also offers enhanced image quality, however total playing time is reduced when the full bandwidth is actually used. At maximum bit rate, an SVCD only stores around 35 minutes of video as against 70 minutes on a VCD.

The default folders created for Super Video CD are not the same as those we created for our VCD.

An (S)VCD is an XA disk with several Mode-2 tracks. The first track usually contains Form-1 blocks with the normal 2048 bytes per block and stores a CD-ROM (ISO) image so that the CD can be read by a PC. Certain files and directories are required by the standards:

(S)VCD: Information about the available tracks and how they must be played
EXT (VCD only): More detailed information about the type of playing; only relevant for CDI players
CDI (VCD only): This directory contains the Philips CDI application and its utilities. These files are licensed by Philips and taken from the Nero root directory. This application is needed for playing tracks on a CDI player.
MPEGAV (MPEG-2 for SVCD): The AVSEQxx files contain the MPEG tracks on the Video-CD. The first track only contains references to the data which are stored not in the first track but in the subsequent tracks. This means that although these files have a long nominal length they do not require much space in the ISO track.
SEGMENT: The ITEMxxxx files represent the encoded single pictures. They are stored in the first track as Form-2 blocks and have a fixed length of 150 blocks.

The encoded files can be played on a PC provided a suitable package such as Windows Media Player is installed. DVD player software is required for MPEG-2.

Other files and directories can be added to the CD-ROM. These are ignored by a player. (S)VCD also supports other special functions such as karaoke and hierarchical menus with pictures, but these are not used by Nero at the present time. Nero simply takes a list of MPEG or picture files and writes them to a CD in such a way that playing starts immediately with the first file, and the player's forward and reverse keys can be used to skip from file to file.

You can set a pause that stops play at the end of every file. The pause is only a value in the description of the file so there is no need to create empty blocks; the pause can be very long or can even be set to infinite, in which case the player is stopped and waits for an input from the user.