VideoCD V2.0 (VCD) is a standard for saving video data on a CD. It gets more data on a CD and allows interactive selection of the CD's contents. Special players such as CDI a DVD players support this format. The video and audio dataflows are compressed with MPEG-1, Audio Level 2 and played at realtime speed (75 blocks a second). Because this format and video/audio data generally tolerate bit errors the space that is normally needed for error correction can also be used for MPEG data. This increases the amount of user data in a block from 2048 to 2324 bytes per block, giving 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 videofilm as against 70 minutes on a 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:
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.