MiSTer FPGA Forum

I have been having problems with the Second Reality Demo for awhile now. It used to run fine all the way through. Now it runs about half way through and then it gets a black screen while the music keeps playing and when that segment of the music ends, the video continues with the next song, so it has the wrong song with what is on the screen. Is anyone else having this problem or does it work for you? I am running MS Dos 7 so I am not sure if that is what broke it. Thanks!

Tested with core 20200922 and ms-dos 6.22 and got desynced audio and video.

Hi ! Would be happy to donate quite a significant amount of money to fund a Gravis Ultrasound implementation But all those developments are driven by passion and the amount of work actually put into them couldn't be funded.

But well, I'm suggesting a Patreon/bounty, just in case

ash2fpga wrote: ↑Mon Dec 07, 2020 5:10 am Tested with core 20200922 and ms-dos 6.22 and got desynced audio and video.

Thanks for confirming. I think this might be an issue with the main file because my old cache 46 core has the same problem and it used to work.

mahen, just curios what the GUS gives us that we don't already have? I guess it would be more efficient in FPGA than the Sound Blaster is in software with mixing mutiple waveforms to produce the music in Second Reality.

Well, I'm not a specialist. I just remember that during a given period of time of the DOS era, games supporting it had a very significantly better sound quality versus software mixing -- which also didn't waste CPU cycles. I was shocked when playing Extreme Pinball and SB16 mode for instance that it sounded really low-fi -- worse than Amiga sounds -- even though I chose a very CPU intensive mode of software mixing.

Also, MIDI using the official GUS patches should be 100% faithful to what we used to get with a GUS, which we cannot achieve when mimicking a sound canvas with Timidity.

Also, some demoscene productions (?) used to only support the GUS or am I mistaken ?

Well, it's very complicated... We need a proper MT32 for early games and a proper GUS for late games and a proper SB for intermediate ones I guess

I'm not a DOS guy though, rather on the Amiga side, just played on my bros' machine.

mahen wrote: ↑Mon Dec 07, 2020 2:56 pm Well, it's very complicated... We need a proper MT32 for early games and a proper GUS for late games and a proper SB for intermediate ones I guess

It is a bit more complex than that..

For MIDI, you need an MT-32 for early games and an SC-55 or SC-88 for the later ones.
For FM, the best option (more compatible) is probably a Sound Blaster Pro. It kind of also covers the ADLib only games quite well.
I'd argue a GUS is only really relevant if you're looking for compatibility with some Demos like Second Reality. Apart from that there is not much it will give you on top of a SB with a SC-88.

Anyway, this is also one of the advantages of FPGA, it allows you to eventually have a flexible system that you could only dream of back in the day.

Cheers,

Yep, there are probably 4 or 5 typical sound profiles :/.

I guess games that had protracker-like soundtracks were really better with a gus, though. My memory of dos gaming around 1995 ? Pinball games for instance. They do not sound right with midi or adlib tracks but are downsampled / badly mixed with a soundblaster. That's probably my Amiga bias though ? (Ex. : extreme pinball, pinball fantaisies, jazz jackrabbit, one must fall... ?)

Went back and retried the demo with ao486 vsync set to variable and the audio/video are now synced.

ash2fpga wrote: ↑Thu Dec 10, 2020 11:20 am Went back and retried the demo with ao486 vsync set to variable and the audio/video are now synced.

Thanks! I am at work, but when I get home I will try it. Much appreciated!

Setting it to variable fixes the issue, but unfortunately it breaks the MiSTer scaler timings and makes my CRT TV go out of sync when using the scaler. What is funny is I can use direct_video and it syncs well enough to watch it during most of the demo. Dos text looks wacky but Second Reality when running looks somewhat decent, at least well enough so that I can see it doesn't have the black screen issue in the middle of the demo.

I am hoping that someone can fix it so Second Reality works with 60Hz, or fix it so that Variable sync works with the scaler. It probably would be fine on my LCD, but I pretty much only use my CRT TV now and so far Second Reality is the only issue I am having with it.

Also, with the latest core, the sword is not coming out as far as it used to, so it appears to be running slower than it once did.

Thanks again for your help.

My guess is that it would require tighter VGA timings before we could get Second Reality displayed at 60hz without any audio/video desync.

I found a writeup of the code from 2013 here: https://fabiensanglard.net/second_reality/index.php

The author mentions a bit about the demo using a simulated (Amiga) Copper in § Copper: https://fabiensanglard.net/second_reali ... ty_dis.php

Thanks! That was a very interesting read. I am looking forward to the eventual future improvements of ao486 that achieve more compatibility. Demos like Second Reality are great at pushing the limits of the hardware and testing compatibility.

Just an update. I solved this issue completely. I can now turn on Variable in the ao486 core on my CRT TV once I set a vscale_mode other than 0, and setting vsync_adjust to 1 to eliminate the dropouts when it changes resolutions. Here are my settings:
[ao486]
; Set it to "Variable" in the ao486 core instead of 60Hz
direct_video=0
vga_scaler=1
vsync_adjust=1
vscale_mode=3
video_mode= 1280, 170, 140,244,240, 2, 0, 22, 29020 ; Best for ao486

I may play with the video mode some more because it currently has black borders all the way around.

Just ran it from beginning to end credits, runs perfectly for me with the actual core. No Black Srceens no sync problems:

I had the Audio "out of sync" Problem too, but setting Vsync to "Variable" in the core "Audio&Viedeo"-Settings fixed it for me. Perfectly synched!
Used Option 2. EMM386 in miSTer ao486 startup menu.
Choosed Soundblaster PRO (Stereo), SQ High

One of the best Demos ever, happy its working so great on miSTer!!

If you need any more Info about settings, just ask.

EDIT: @thorr, you solved it the same way, too Sorry, 2l;dr