Question About PS1 & VideoCD Card

So these days with the exploit for PS2 using a patcher to make the PS2 games look like DVD-Video discs to enable the system to read the burned games, I was wondering about this. From what I can tell, any PS1 with the parallel I/O port could have the PS1 Video CD card plugged into it.

But my question is then, does the PS1 consider a Video-CD format disc valid to read from? Or more specifically what does the PS1 allow you to read from and not? I was under the impression that there were only 2 types of discs the PS1 would let the CPU read from. Original PS1 CDs, and Audio CDs. But if you can play Video CDs simply by plugging in this device into the I/O port like you would a GameShark, doesn't that mean the Playstation considers a Video CD valid to read data from? And then couldn't you make the leap that if you "patched" PS1 burned discs to look like a Video-CD and made a loader on a GameShark or PAR cartridge you could avoid needing a modchip at all?

Or when people use this "Video Cd Cards" are they doing a swap trick?
I'm just curious if anyone knows anything. I do recall hearing some GameShark Update type of CD you could burn and your system would read because they used some sort of file system hidden in the audio track of a audio cd. Just wondering what other goofy stuff could have been done.

 

I believe they do a swap trick...

One video CD card for the PS1 that you solder onto the board requires a modchip.

 

The thing is, there's one of these VCD cards that is made BY SONY. Apparently. So I'm wondering about that as I'd doubt that Sony would actually endorse the swap trick. See here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=260328333808

 

Made in China... NOpe, not sony... Lik Sang used to carry those because I remember that exact shape and it is what you posted.

I believe that model uses the swap trick though...

If you have the small one, you can get this:

http://www.amazon.co.uk/gp/offer-li...p_0/275-4023372-8540650?ie=UTF8&condition=all

 

VCDs are mode 2 just like PS CDROMs, I don't think any trickery is necessary to read them. Also though the unit is huge, I wouldn't count on there being a MPEG decoder inside, it could very well just be a software player on Action Replay hardware in a big case.

 

I'd respect the PS1 for decoding MPEG1 just on the CPU... on a slightly related note, I once read in an old magazine that the MDEC chip actually could decode VCD but that it was "disabled" or something... probably bunk anyway.

Also, the PS1's BIOS is not that uptight about reading from the drive as the Saturn for instance, no? In fact I remember it letting you read files straight off an "unauthorized" disc, just that the BIOS wouldn't boot the EXE from it.

 

I actually had one of them when i was younger, don't know were it came from but got it with a playstation my dad bought for me from his mate at work and i don't sony ever made one.

 

Sega Saturns have a dedicated daughter expansion slot (is that what they are called?) for upgrades, such as MPEG VCD cards. Those cards perform hardware decoding and the Saturn was build with these in mind for the future. In fact Sega made their own brand of VCD decoder cards.

From what I understand, the Playstation did not have any forsight into add-ons like a VCD adapter. Everything made for the PS1 was after-market and I have my doubts if they did any video decoding in hardware. I suspect the VCD adapters released for the PS1 were simply dongles that contained custom VCD playback software. I assume it would be easier than pressing your own CD-ROMs with copyprotection intact and plus you could charge more money for it. I'd also suspect that you'd probably need to swap CDs to fool the system into reading your VCD to begin with so making an sudo Action reply system would be ideal also.

PS: Is the PS1 expansion port even fast enough for transfering large amounts of data? Beats me. Obiously it wasn't fast enough for RAM expansion?

 

But the discs aren't valid PS1 game discs. I don't think the PS1 would read from any Mode 2 disc simply because if it could then any GameShark or PAR cartridge could have forced the system to boot burned/bootleg games without a modchip.

So Sony didn't ever make an official VCD card addon? Which would suggest to me that the VCD players all require a swap trick or modded system. The only except would be that Video-CD PS1 system that has support built in I guess.

 

Ah... Thats why they have ports at the end. At first I thought they were just passthrough connectors because the back was so big it would block the regular connectors from making it out.

 

I strongly recall it being clocked at a mere 4mhz with a 8-bit wide bus (or was it 16? can't remember), so not terribly fast, no.

 

It's basically the same thing as the PSX parallel I/O, the VCD card is just a memory mapped device.

To unlock the CDROM, you need the SCEX data. It's not likely there's any way for the CPU to upload new firmware to get around this, the system is surely designed this way on purpose.

Yes, by far fast enough for VCD upload (150KiB/s), and possibly download (~5MiB/s). It's certainly fast enough for RAM expansion too; it's not like Saturn's expansion RAM/ROM ran at the same speed as the CPU(s), not even close.

The MCU needs the disc to be authenticated, but after that the CDROM's free.

I'm pretty sure it's a 24 x 16-bit bus, indicating it's the CPU bus, meaning it's quite possibly full speed (well, RAM speed at least). Obviously it works differently in bootstrap mode for the slow 8-bit AR FlashROM, but dunno how.

 

For a VCD unit, they are below average... THe CDi runs it better .

The internal ones, however, if you are talking about the model for the PSOne console, then those used to be abundant on lik-sang. Almost bought one but they were... $99? at the time? Or $50, I don't really remember.

 

It would be cool to see the insides of one of these. If it uses a hardware MPEG decoder (like this: http://pdf1.alldatasheet.com/datasheet-pdf/view/167556/SONY/CXD1856Q.html ) I can see why the whole external video thing was necessary, most of these chips just output the video for you unfortunately. It's really no wonder VCD were so popular in China, you could cobble together a player from a single LSI and obsolete junk parts.

 

Calpis, so you're telling me it was entirely possible that PS1 could have had a RAM card plug into the expansion port and have non-sucky ports of games like Metal Slug and Marvel Vs SF like the Sega Saturn did?

If this is what you are saying, I think someone needs to be flogged for them not doing this. It would have been extremely awesome.

 

Sure, at worst it could have been slow paged RAM like the Arcade Card, and at best, 48M of extra WRAM.

 

Well, it deserves noting that this port DOES have special connections to VDP2, allowing it to blank/overlay its own video without the CPU intervening. That's pretty cool I think, it actually would have allowed a 3D upgrade.

You sure? I thought Caetla-uploaded programs could read files off the disc, but then, I haven't done any PSdev in over 2 years.

 

Nope, not at all

 

I've always heard the PS1 works like this. When you put in any disc, the CD controller will check the type of disc and if it is a PS1 disc it is verified for security and region. If it fails then you can't read anything off the disc with the CPU. But if it passes you are free to do whatever until the lid is opened which is why people do the swap trick. Though there is the problem with the Table of Contents of the CD you started with is still in effect. I've heard and noticed that any games using Audio tracks will not work right because of this and also that if the game is just a 1 data track disc is shorter/smaller than the disc you swap to it will be unable to read beyond what the original TOC said.

But I wonder if like the PS2, if you could fool the PS1's security by patching the ISO not to look like a PS1 game but like a CD it could read like an Audio CD but then have a loader on a PS1 cheat cartridge that could boot the altered disc.