Anyone care to comment in-depth on the PC-FX hardware design?

[SamIAm]

That's all very interesting. Thank you so much for taking the time to share!

[Arkhan Asylum]

Ridiculous Parallax! LETS GO

[SamIAm]

This is actually a pretty unique idea. It might sound like another crappy FMV project like what came out of the 90's, but with a little seasoned-action-gamer common sense, you could make an auto-scrolling or Super Mario Bros. 1-style scrolling platformer with good gameplay and a totally unique graphical look.

Imagine if you could get five people around the world each with decent cameras and well-suspended cars. You could have everyone drive by two or three unique areas each, maybe within certain speeds for consistency, getting a total of 30 minutes or so of good side-scrolling footage. That would be plenty for a sweet little platformer, and it really wouldn't be that difficult. Then you would just have to draw some foreground and sprites. It would look kind of like Umihara Kawase or something. Which, by the way, I think has underrated graphical design.

I don't have a car, but I could maybe get some sweet train-window footage here in Japan.

[saturndual32]

Regarding the PCFX not being able to handle Doom. I have read that the 32X port of Doom was made using only one or the SH2 32bit 23MHz chips on the system. The PCFX 32 bit 21mhz should give similar performance to that, right?, and the FX has way more ram than 32X. I thought that Doom 32X was deccent technically for the time, albeit rushed. Also 32X and PCFX share the RLE rendering method, can someone mention what it is all about?
From what i remember, 25mhz PCs played a decent game of Doom, back in the day, without any sprite hardware, and with about 2 MB or RAM, so i think the FX should be able to do an ok port of it.
Then again, i would trust more the opinion of guy like trap15, than i would trust mine, hehe.

[saturndual32]

Wow, hadnt realized how weak the sprite capabilities of the FX were, only 128 sprites, same as SNES can do on paper, and without scaling or rotation effects. Although i guess that like 32X, it can do many scaling and rotating sprite in software, like 32x does for games like Space Harrier, Knuckles Chaotix, etc.

On the other hand, it has great background capabilities. So it has the 2 background planes from the Supergrafx, the MJPEG layer, and 4 from the King procesor. One of the Kings planes is a mode 7 type plane, i think another one is called "xelophane" layer, can someone comment what it is all about? And what about the 2 remaining King planes, are they more common ones? Also, i guess the King planes have way better color capabilities than the 7UP planes and sprites, right?

Anyway, i think this system could have been the last great 2d system. Just as Saturn and Playstation jumped into the 3d scene, the FX could have had the 2d scene all for itself, just by getting 32bit sequels to all the amazing PCEngine games like Bonk FX, YS FX, Star Soldier FX, etc, and also ports of stuff like Castlevania Symphony of the Night, Rockman X4, Street Fighter Zero 2... it would have been amazing...darn it NEC!!!

[SignOfZeta]

This is actually a pretty unique idea. It might sound like another crappy FMV project like what came out of the 90's, but with a little seasoned-action-gamer common sense, you could make an auto-scrolling or Super Mario Bros. 1-style scrolling platformer with good gameplay and a totally unique graphical look.

Imagine if you could get five people around the world each with decent cameras and well-suspended cars. You could have everyone drive by two or three unique areas each, maybe within certain speeds for consistency, getting a total of 30 minutes or so of good side-scrolling footage. That would be plenty for a sweet little platformer, and it really wouldn't be that difficult. Then you would just have to draw some foreground and sprites. It would look kind of like Umihara Kawase or something. Which, by the way, I think has underrated graphical design.

I don't have a car, but I could maybe get some sweet train-window footage here in Japan.

This could work, maybe, with some good planning. Cars move around a lot more than you might realize, but if you had a really smooth road, good suspension, a camera that was fixed to the car very solidly, a camera with stability control, and you shot rather far into the distance, it could work. Anything other than that and its just going to shake all over the place.

I honestly like the idea of a hand drawn loop better. Kind of like Iridion with taste. You'd only need to draw about 20 full frames for platformer walking action. Mix things up with foreground sprites. When you get to a new area you can fully animate transitions to a new loop, repeat. Why has this never been done. Has it been done?

I might actually try this when I'm bored at work. If someone could combine this with the "Joust as an action RPG" idea...we could have the best fucking game ever.

[thesteve]

as for playing doom on PC BITD a 486-100 fought with it.
wolfinstein however ran great on a 286-11

[HercTNT]

Are you sure your thinking of doom and not quake? I had an Amd X5-133 with 16 megs of ram back then, and I could run quake at around 10fps.  At the time i was not aware of the crap fpu unit the Amd chips had. If it had been an intel chip, its gaming performance would have been twice as fast.  Doom should skip along pretty well on a fast 386.  As for the saturn, technical specs amount to nothing. The saturn may have had two cpu's and a fancy 3d chip for the time, but as other pointed out it was horrible to program for. Most saturn games never used the second cpu. The video was provided by Nvidia's NV1 and instead of outputting 3d in polygons it outputted 3d in quadratics. Since everyone else on the planet was using polygons, retooling everything to program in quadratics sucked hard.  Besides its not the hardware that matters in alot of cases, its the quality of the programmers.

[SamIAm]

Regarding the PCFX not being able to handle Doom. I have read that the 32X port of Doom was made using only one or the SH2 32bit 23MHz chips on the system.

I kind of doubt that, but there's an easy way to check. Run Doom with Gens, but go into the config file before you launch the program and underclock the slave SH2. You can almost never get away with turning it "off", but I do remember from when I tinkered with it that a lot of games run with no slowdown even with the slave below 50% speed. I'd bet a friend a cheap beer that Doom gets sluggish below 80%, though.

When you get to a new area you can fully animate transitions to a new loop, repeat. Why has this never been done. Has it been done?

It's a shame how many things haven't really been tried and/or refined in the world of 2D game graphics. If development companies these days gave people real money to make 2D games and encouraged them to go for non-traditional graphical styles, we could wind up seeing all kinds of crazy crap. Just think: if the next generation of consoles have 4+ gigs of ram whenever they come around, the possibilities for animation will be absolutely huge. The key thing is, we need people to evolve the medium, and next to nobody is doing that.

It's kind of like when Odin Sphere came out on the PS2, and everyone said "Why the hell haven't there been more games that look like this?"

Such a shame.

[Arkhan Asylum]

All these modern consoles are dreamlands for glorious 2D artwork.

So much space and power to do crazed 2D stuff that wouldn't even dent the CPU.

Only games that seem to do anything with it are the JRPGs from NIS/Atlus. 

I personally cannot stand 2D games that use 3D rendered nonsense.  hand-drawn or GTFO.

[SamIAm]

I personally cannot stand 2D games that use 3D rendered nonsense.  hand-drawn or GTFO.

You know what I think would be cool? A 2D Castlevania game where all the backgrounds are hi-color, hi-res scans of actual 17th century-style paintings. They could hire a bunch of art students and make original material or whatever. There's so many ideas...

[Arkhan Asylum]

fuck that lets just go scan a bunch of art books and shit and diddle up the colors so it looks video-game-like.

[Keranu]

I personally cannot stand 2D games that use 3D rendered nonsense.  hand-drawn or GTFO.

You know what I think would be cool? A 2D Castlevania game where all the backgrounds are hi-color, hi-res scans of actual 17th century-style paintings. They could hire a bunch of art students and make original material or whatever. There's so many ideas...

That's a really good idea! Like that one a lot, could add lighting effects via hardware too to add some liveliness.

[SamIAm]

^^^I guarantee that nobody has seen anything quite like a painting coming alive with parallax, palette shifts and transparencies.

Anyway, back on topic, I thought of another question. Does anyone have any speculation about why the PC-FX uses so much PCE hardware? To my understanding, it's got basically all the sound and video hardware in there. Do you think it was because they were hoping to achieve backwards compatibility but abandoned it partway through the design process, like the SNES going with the 65c816 because it was b/c with the NES CPU? Or do you think it's because they were hoping to take advantage of developers' familiarity with the hardware?

If it wasn't that kind of decision, could it have just been a cost-cutting measure? Or something else?

As I think about it, I can understand using the PCE sound chip as a quick solution and a cost-cutter, but the two 7ups and KING combo seems a little odd. Surely they could have found another video solution that was similarly priced, more simple and, if only for 2D, more powerful.

[SignOfZeta]

The absolute state of the art in 2D gaming these days is actually coming from...Bandai.

It's true. Check out Super Robot Wars Z2 (PSP) and Kamen Rider Generations (DS).

[Arkhan Asylum]

They chose to stick with the same kind of PSG because it sounds fucking amazing.  True story.

[saturndual32]

I agree with Psycho Arkhan, about the PCE soundchip being awesome, but at least they should have used 2 for the PCFX, like they did by using 2 7UP videochips instead of one.
Anyway, i see that the FX has 3.75MB of RAM, does anyone know how it is divided. I wonder if it had enough video RAM to do a port of Street Fighter Zero 2 comparable with the Playstation and Saturn.

[Arkhan Asylum]

DUAL PSG?

omg I just peed myself.

[Nando]

yeah, drawing in any form is laborious for me.

I don't know if there is anyone who would really want to do something like that.   It's too much goddamn work.

"Hey draw, a 3 hour show for me, cmon"

labour intensive to say the least, but well looped animation bits could work. It would come down to a really Type-A grip on the art direction, to make sure it works. Then finding an OCD team to do the animations

[SamIAm]

All right, after spending boatloads of time messing with Zeroigar's MPEG videos, I think I can comment a little on the PC-FX's FMV playback.

Zeroigar's movies are 256x208 pixels, with approximately 30 horizontal lines and 8 vertical lines of blackness around the real video. They run at 12 frames per second, have 31.5kHz stereo sound, and average about a 227kB/sec data rate for playback. Note that this is not a totally constant data rate; there's actually quite a lot of variation over time.

Within these parameters, the PC-FX appears to have fairly decent and versatile video playback. I'm just speculating, but because the drive can go up to 300kB/sec, I suspect that you could maintain similar quality going 15 FPS at the same resolution and sound quality, even with no black areas. With no room for variability, though, some things might not encode well.

With the sound set to 22.1kHz mono, I'd imagine that 20 FPS would work fine, assuming that the system can re-portion the bandwidth.

The tool I'm using for encoding the Zeroigar videos has a maximum of 256x240 resolution. Whether the system itself can go higher than that, I can't say. Also, while the maximum sound quality appears to be 44.1kHz stereo, it can go all the way down to 15.8, 11, 7.9 or 3.9kHz mono. FPS rates include 30, 20, 15, 12, 10, 6, 3, 2, and 1.

Finally, one thing to note is that visually active footage at 30 FPS is probably going to look terrible when coupled with any kind of decent sound and resolution. I would be surprised if any games used 30 FPS at all.

[KiddoCabbusses]

Are you sure the PC-FX doesn't have a 25 FPS rate? I mean, I would've thought that'd have been a normal framerate by that time... hrm...

Anyhow, I always thought Battle Heat's OP looked incredibly visually active, even compared to other PC-FX games;

Since that seems like it pushes the limits of what the PC-FX's FMV playback can do, would you mine telling me what it's specifications are?

[SamIAm]

The framerate kind of needs to multiply evenly into 60, so 25 FPS doesn't really work. Movies filmed at 24 frames per second go through 3:2 pulldown to work in 60Hz interlaced TVs. Modern games that don't use frame-based timings update the screen with whatever the latest image is that the GPU has drawn, and so they can have pretty much any rate imaginable.

EDIT: OK, looking at a rip of that youtube Battle Heat video was confusing. Since I don't have a copy of that game, I popped the Tengai Makyou fighter into Mednafen instead and set it on frame-advance mode for the intro to make sure I knew what the system was doing. This and Battle Heat are similar enough. What I found is very strange.

The framerate for Tengai Makyo in particular is highly variable. Most of the time it alternates between 15 and 30 FPS, but usually the rate changes so rapidly that you can't really call it a rate. The system has to draw to the TV at a locked 60 FPS, but you'll see the image updated in 2 frames, then 4 frames, then 2, then 2, then 4 and 4 and 4, and then occasionally 3. That's what Battle Heat appeared to be doing as well, although with a little less variation. They must be using a unique format and encoding method.

Usually the moments when the image was updated in 2 frames/60 (30 FPS for that instant) were parts with relatively less change in the frame, presumably for compression reasons. They must have planned the hell out of this.

The video is 256x232, which beats Battle Heat if the youtube video is any indication. I can't quite hear if the sound is mono or stereo with my current setup, but it doesn't quite sound like 22.1kHz. I'd be stunned if it was 44.1kHz stereo with this quality. It would mean that somewhere out there is encoding software for the PC-FX that beats the pants off the software included with the GMAKER/PC-FXGA publicly released stuff.

It's not really possible to know the details about the sound for sure without accessing the video at the source, though.

[Mednafen]

The possible PC-FX ADPCM playback rates are ~31468 Hz, ~15734 Hz, ~7867 Hz, ~3934 Hz.  (Of the pattern 31468 / (2 ** n), which allows for very computationally-inexpensive linear interpolation at the < 31468 playback rates, by right-shifting the delta step by 1 to 3, while still adding the shifted delta step value to the predictor at 31468 Hz).

The ADPCM encoder that (most?) commercial games used is buggy(the GMAKER one is buggy too IIRC); it uses an algorithm that is mismatched to how the PC-FX actually decodes, which results in the audio being noisier than it should be.

For practical purposes, the JPEGish decoder chip can only display at 256x240 maximum.

The decoding is semi-real-time, with a 256x16 automatic double-buffer setup(decodes into 256x16 buffer A while displaying buffer B, then displays buffer A while decoding into buffer B, etc).  Kind of overkill as far as computational power required goes, but makes more efficient use of RAM I guess.  This means that 60FPS FMV is no problem as far as the decoder chip is concerned, at least.

[SamIAm]

Thanks for the post, Mednafen.

I was thinking 44.1kHz was an option because it's available in GMAKER, but sure enough, trying to encode a video with that doesn't work at all, regardless of what the source is.

Having said that, I just tried making a PC-FX video with 30 FPS source material and output settings of 30 FPS, stereo 31.5kHz sound, and a 300KB/sec limit. It wasn't as bad as I was expecting. I must have overestimated things after spending so much time re-encoding videos that were lossy to begin with.

EDIT: Oh, and if anyone is interested, Megami Paradise II is a solid 12 FPS with 256x232 resolution, minus about 12 horizontal lines total of blackness.
Also:
Sparkling Feather is 256x232 @ 12 FPS, about 8 vertical lines of black on the borders
First Kiss Monogatari has a 30 FPS bit for the company logo at the beginning, but then goes back to 12. Forgot to check the res.
Zenki is like Tengai Makyo, with highly variable rates averaging around 20, as well as 256x232 resolution with no borders. For now, it appears that these two games have the best video on the system.
Finally, Battle Heat is 256x232, but its huge black borders make it 256x160. Like the previous two, the rates are highly variable, but with an interesting twist. There are long sections of 30 FPS, but they are preceded by moments of 10 FPS, maybe to fill up some buffer.

[KiddoCabbusses]

It's not really possible to know the details about the sound for sure without accessing the video at the source, though.

I got a legit copy of Battle Heat (wish I could say the same for the Tengai Makyo game) and would be more than willing to do a rip for analysis sake. (Although more than likely if I'd have to transfer an ISO image around I'd may as well download one..)

I wouldn't really have the ears for being able to gauge the quality of the music in the games, except I'd think Tengai Makyo's music generally doesn't sound like it was as encoded in as high a quality. (Although this may just be the ol' "OMG LYRICS N' VOCALS" mindset here, but then again, if the audio quality had any really noticable decay comparing the FMV file and the CDDA audio version on the disc, it'd probably be most notable -in- the vocals... ... my lord, am I overthinking this.)

[SamIAm]

That's very kind of you, but I had actually just downloaded a rip to check for that last post I made.

Anyway, Mednafen more-or-less answered our question for us. If our only options are 31.5kHz, 15.8kHz and a couple that are much less than that, we can be pretty sure that most games use 31.5kHz. 15.8kHz sounds pretty low-fi. Lunar 2 on the Sega CD used 16kHz streaming music, to give you an idea (although it also had an 8-bit sample rate instead of 16). The only question left is whether each video is in stereo or mono.