Sega LaserDisc hardware
From Sega Retro
Sega Laserdisc hardware is an arcade system produced by Sega in 1983. In addition to having a PCB and ROMs, the games made use of Laserdiscs for full-motion video. Additional graphics and an HUD could be placed on top of the video sequences.
GP World and Time Traveler, two other Sega-produced Laserdisc games, run on different hardware from this. A third game, Albegas/Cybernaut (1983), is known to exist, but not much information is known about it.
Hardware
It was the first system dedicated to producing laserdisc video games. The first game to use it was Astron Belt (1983) and the last to use it was the holographic game Time Traveler (1991).
It used one of four laserdisc players, either a Pioneer LD-V1000 or LD-V1001, or a Hitachi VIP-9500SG or VIP-9550. Two different versions of the laser disc itself were also pressed, a single-sided version by Pioneer and a double-sided version by Sega. However, both discs have the same information and may be used in any of the four players.
The hardware combines laserdisc footage with a real-time 2D computer graphics plane. The real-time graphics plane was overlaid by imitating a matting technique. As the CRT monitor scans horizontally across the screen, it is fed information from the laserdisc up until the point where it is fed information from the computer graphics system, after which information coming from the laserdisc stops, creating a black mask into which a sprite is inserted. It uses a collision detection system where both the laderdisc and sprite planes can interact with each other. Each frame of the laserdisc footage is coded with a hit detection spot stored in ROM memory. The Zilog Z80 CPU microprocessor reads the number of the laserdisc frame, and checks the laserdisc hit spots with the shots fired by the player, and if the coordinates correspond, it instructs the laserdisc player to display an explosion sequence. For sections where the player must navigate between walls, the walls in the laserdisc footage are also coded and use collision detection.[1]
![[1]](#cite_note-http:.2F.2Fwww.dragons-lair-project.com.2Fcommunity.2Frelated.2Farticles.2Fallgames.2Fpic4.gif-1){kind=link}
Technical Specifications
- Hardware: PCB + Laserdisc player
- CPU: Zilog Z80 @ 5 MHz[2] (8-bit & 16-bit instructions @ 0.725 MIPS)[3]
- JAMMA board: Sega PCB CN1[2]
- Audio board: Sega PCB CN2 (stereo output)[2]
- Laserdisc player: Hitachi-Sega VIP-9500SG,[4] or Hitachi VIP-9550, or Pioneer LD-V1000, or Pioneer LD-V1001
- Video resolution: 580×480 (580 dots, 480 lines), 525 scanlines (480 visible),[5] interlaced video
- Refresh rate: 59.94 Hz[2]
- Frame rate: 29.97 frames per second
- Color depth: 16,777,216 (24-bit true color)
- Audio: LaserDisc, stereo output
- Real-time 2D graphics overlay:[2]
- Display resolution: 256×256 pixels, progressive scan
- Refresh rate: 59.94 Hz
- Color palette table: 512 (PROM)
- Colors on screen: 256 (color RAM)
- Tilemap plane:
- Tile size: 8×8 pixels
- Tilemap size: 32×32 (1024) tiles, 256×256 pixels
- Colors per tile: 2
- Sprite plane:
- Sprite sizes: 8×8 to 256×8 pixels
- Sprites on screen: 32 sprites per scanline, 256 sprite pixels/texels per scanline
List of Games
- Astron Belt (1983)
- Cobra Command (1983)
- Galaxy Ranger / Star Blazer (1983)
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