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Video CD &
Super VCD
Until DVD, Video CD offered the highest quality
video on a compact disc |
Video CDs are defined in the White Book. They contain
MPEG-1 audio and video for
mainly linear video applications. Video CDs are multi-track,
CD-i Bridge discs designed
also to play on CD-i players.
The Video CD specification was written by
Philips, Sony, Matsushita and JVC. It is a generic format which (like audio CD) is
hardware independent. The original version was for Karaoke CD as a replacement for the
ageing VHD video disc systems used in many Karaoke bars in Japan.
Special purpose designed Video CD players have
been developed in the Far East as enhanced CD players with Video CD capability. Generally
they offer a lower cost solution for playing Video CDs, as well as audio CDs, but not
other CD-ROM/CD-i discs.
Despite the introduction of DVD-Video, Video
CD has been given a new lease of life (particularly in China) with the introduction of
newer versions including
Super Video CD.
Please note that Video CD (VCD) and CD Video
(CDV) are not the same thing. the latter format is a combination of CD audio and analogue
video.
Video
CD Features
The main features of the Video CD specification are listed in
the table below.
| Parameter |
Value |
| Playing
time: |
74 minutes |
| Video: |
MPEG-1
encoded video |
| Resolution: |
352 x 240 at 30 fps (NTSC) or 352 x 280 at 25 fps
(PAL/SECAM) |
| Audio: |
MPEG-1 stereo and optional CD audio tracks |
| Stills: |
MPEG-1 at up to 720 x 480/576 (can be used for menus) |
| Interaction: |
Menus to select entry point
Playlists for predetermined video/still/audio sequences
Fast forward and reverse |
| Subtitles: |
Closed captions |
| Entry
points: |
Up to 98 entry points per track (500 total per disc). |
Video CD discs also contain a CD-i program so
they will play on CD-i players.
Video CD
Tracks
White
Book Video CDs are characterised by the use of multiple Tracks.
Track 1 contains the
following data:
- CD-i application program.
- Track information for Karaoke or music
videos (optional).
- Entry point addresses
- Playlists
- MPEG stills.
Tracks 2 upwards are used for the MPEG
video data (optionally followed by audio tracks) files which also can contain the scan
table information and closed caption data in the user data area. A Video CD disc must
therefore contain at least two tracks. The MPEG video files only are
contained in Mode 2, Form 2 sectors. Optional CD audio tracks can be added
after the last MPEG track.
Video CD Directories and Files
Most files on a Video CD disc have predefined filenames and
are located in specific directories as shown below.
| Directory |
Files |
Comments |
| VCD |
INFO.VCD
ENTRIES.VCD
PSD.VCD
LOT.VCD |
Album and disc identification
Entry point list (500 max)
Play Sequence Descriptor
List ID Offset file |
| MPEGAV |
AVSEQnn.DAT |
MPEG files (one per track) |
| CDDA |
AUDIOnn.DAT |
CD Audio files (one per track) |
| SEGMENT |
ITEMnnn.DAT |
Segment play items (one per segment) |
| KARAOKE |
KARINFO.xxx |
Optional Karaoke information files |
| EXT |
PSD_X.VCD
LOT_X.VCD
SCANDATA.DAT
CAPTnn.DAT |
Optional extended version of PSD.VCD
Optional extended version of LOT.VCD
Optional list of I-frame addresses
Optional Closed Caption data (one per track) |
| CDI |
(undefined) |
CD-i program and data files |
Super Video CD (SVCD)
Philips has released the specifications
for this new version of Video CD called SVCD. This format includes many of the features of
DVD-Video but without the long playing time. The following table compares SVCD with Video
CD ver 2.0.
| Parameter |
Video CD v 2.0 |
SVCD |
| Playing
time: |
74 minutes |
35 to 70 mins+ |
| Data rate: |
150 kBps |
300 kBps |
| Video: |
MPEG-1
1.15 Mbps CBR |
MPEG-2
2.6 Mbps average VBR |
| Resolution: |
352 x 240 (NTSC)
352 x 280 (PAL/SECAM) |
480 x 480 (NTSC)
480 x 576 (PAL/SECAM) |
| Audio: |
MPEG-1 stereo CBR
optional CD audio tracks |
2 streams MPEG-1 stereo VBR
optional 5.1 channel |
| Stills: |
MPEG-1 |
MPEG-2 |
| Interaction: |
Menus, Playlists,
Fast forward/reverse |
More interactivity |
| Subtitles: |
Closed captions |
Overlay graphics
(4 selectable channels) |
| Entry
points: |
Up to 98 per track
(500 total per disc). |
|
Super VCD allows a full length movie to be stored on two or
three discs. Multi-disc players can give near-seamless, uninterrupted playback of movies
using this format. The use of MPEG-2 VBR (variable bit rate) video encoding, as used for
DVD-Video, gives improved
quality without an unacceptable reduction in playing time.
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