Laserdisc game cartridge

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems. See the NESdev wiki for more information.

Moderator: Moderators

Post Reply
stevexyz
Posts: 4
Joined: Sat Dec 18, 2021 8:21 am

Laserdisc game cartridge

Post by stevexyz »

I've recently been exposed to NES architecture and for what I understood with the current "enormous" memories we have around should be fairly easy to develop a player for laserdisc-like interactive games. Should it be really quite easy? Has anyone ever tryed?
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: Laserdisc game cartridge

Post by lidnariq »

In the "normal" way of interacting with the NES's PPU, you're fairly limited in the amount of bandwidth you have - about 100-300 bytes per vertical redraw, which isn't really enough to do much in the way of full motion video.

You can also change how the existing pictures appear using bankswitching. This can't rely on any compression, so each screen will take around 14KB of image data, and the largest suitable external memory you can buy is 128MB, or about 6 minutes at 30Hz.

In the "cheaty" way of interacting with the NES's PPU, you can stream arbitrary 13-color pictures. This is basically TheRasteri's Doom cartridge.
User avatar
Dwedit
Posts: 4924
Joined: Fri Nov 19, 2004 7:35 pm
Contact:

Re: Laserdisc game cartridge

Post by Dwedit »

With a huge CHR ROM size, and CHR bankswitching, you can stream arbitrary 4 color video. But you don't get this sort of thing with a flash cartridge. You'd need a lot more CHR-RAM preloaded with your video content than what a flash cartridge would provide.
Here come the fortune cookies! Here come the fortune cookies! They're wearing paper hats!
Pokun
Posts: 2681
Joined: Tue May 28, 2013 5:49 am
Location: Hokkaido, Japan

Re: Laserdisc game cartridge

Post by Pokun »

If you lower your expectations enough you could at least do some cool full-screen animations the "normal" way and without needing anything more than found on a standard flashcartridge like the Powerpak or Everdrive. Though a flashcartridge might not have enough memory for an interactive FMV game.
Check out the NES version of Bad Apple and F-Theta.
stevexyz
Posts: 4
Joined: Sat Dec 18, 2021 8:21 am

Re: Laserdisc game cartridge

Post by stevexyz »

lidnariq wrote: Sat Dec 18, 2021 2:00 pm You can also change how the existing pictures appear using bankswitching. This can't rely on any compression, so each screen will take around 14KB of image data, and the largest suitable external memory you can buy is 128MB, or about 6 minutes at 30Hz.

In the "cheaty" way of interacting with the NES's PPU, you can stream arbitrary 13-color pictures.
This is exaclty what I was thinking. Six minutes are more than enough for each scene to run with the "main line" and all the death sequences included (in fact much less since even the longest one should not exceed 2 minutes). At the beginning of the scene a storage memory (eg. an SD card) can be accessed to populate the new uncompressed sequence in the paged memory. And 13 colors are limited but should provide a reasonable graphic!
User avatar
Ben Boldt
Posts: 1149
Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: Laserdisc game cartridge

Post by Ben Boldt »

Interesting concept, attaching a laserdisc to a Famicom. Seems period appropriate. I have a some questions.

Why use an SD card and a laserdisc player? Why not just store your video on the SD? Having new technology SD seems to undermine the purpose of the ancient laserdisc.

How do you plan to create a custom laserdisc? I am not aware of burnable laserdiscs.

Have you thought about how to control the laserdisc player? It seems these players do have a simple interface for that purpose, usually for connecting to a PC. Is that what you plan to use?

Do you plan to route the video through the Famicom, or would you have an external controllable switch box to switch the video signal back and forth between the 2? What are your ideas for that circuitry?
stevexyz
Posts: 4
Joined: Sat Dec 18, 2021 8:21 am

Re: Laserdisc game cartridge

Post by stevexyz »

Ben Boldt wrote: Mon Jan 03, 2022 3:14 pm Interesting concept, attaching a laserdisc to a Famicom. Seems period appropriate. I have a some questions.

Why use an SD card and a laserdisc player? Why not just store your video on the SD? Having new technology SD seems to undermine the purpose of the ancient laserdisc.

How do you plan to create a custom laserdisc? I am not aware of burnable laserdiscs.

Have you thought about how to control the laserdisc player? It seems these players do have a simple interface for that purpose, usually for connecting to a PC. Is that what you plan to use?

Do you plan to route the video through the Famicom, or would you have an external controllable switch box to switch the video signal back and forth between the 2? What are your ideas for that circuitry?
SD was supposed to replace the Laserdisc. In case of period appropriateness then also a more simple and economic CD ROM might be used!
wendelscardua
Posts: 20
Joined: Fri Jun 26, 2020 2:57 am
Contact:

Re: Laserdisc game cartridge

Post by wendelscardua »

stevexyz wrote: Mon Jan 10, 2022 5:27 pm
Ben Boldt wrote: Mon Jan 03, 2022 3:14 pm Interesting concept, attaching a laserdisc to a Famicom. Seems period appropriate. I have a some questions.

Why use an SD card and a laserdisc player? Why not just store your video on the SD? Having new technology SD seems to undermine the purpose of the ancient laserdisc.

How do you plan to create a custom laserdisc? I am not aware of burnable laserdiscs.

Have you thought about how to control the laserdisc player? It seems these players do have a simple interface for that purpose, usually for connecting to a PC. Is that what you plan to use?

Do you plan to route the video through the Famicom, or would you have an external controllable switch box to switch the video signal back and forth between the 2? What are your ideas for that circuitry?
SD was supposed to replace the Laserdisc. In case of period appropriateness then also a more simple and economic CD ROM might be used!
There's a new mapper being developed, called MXM-1, aiming exactly that: by reading from an SD card, it's possible to make a NES game with FMVs, as if the NES had received CD ROM support at its time.

This is the developers' twitter: https://twitter.com/somethinnerdy, and here is a video of their rendition of Bad Apple running on a NES w/ an Everdrive N8 Pro: https://www.youtube.com/watch?v=WPUYjDNks9Y&t=7s
stevexyz
Posts: 4
Joined: Sat Dec 18, 2021 8:21 am

Re: Laserdisc game cartridge

Post by stevexyz »

Very nice and exactly what I was thinking. From the video description:
Bad Apple playing live on the NES via the new MXM-1 memory mapper. 30.05FPS at full screen (256x240) along with 44.2KHz 7-bit mono PCM. We run this from an EverDrive N8 Pro on an unmodified frontloader NES in this video. (It also works on the Famicom version of the N8 Pro.)

No expansion audio is being used for this. Neither is any co-processor, decompressor, video decoding, etc. All that we are doing is loading chunks of data from the SD card into CHR-RAM and continually re-pointing the PPU at them just in time to render the video in a pixel-perfect fashion. We interleave the video writes with the audio writes and have just enough time to support full 44.2KHz PCM.

(Note: this is not DPCM...it is the real thing!)

This video is frame-for-frame identical to the original except for the reduced resolution and color depth.
PS: I found also the total amount of videos for example in the real original Dragon's Lair: 22 minutes (in wikipedia there is "In total, the game has 22 minutes or 50,000 frames of animated footage, including individual death scenes and game over screens")
Post Reply