Subject: Re: Z26, VSYNC, Timers, somebody HELP ME! (was: Re: [stella] Gunfight Release Candidate(s)) From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx> Date: Fri, 9 Nov 2001 17:00:00 +0100 |
This is an answer to the messages of Thomas, Andrew and Manuel. Thomas: > Are the values between NTSC and PAL different? The TIA changes the sound output twice per scanline, and the PAL VCS operates at a slightly slower clock frequency than the NTSC one. So the sound frequencies are a little differerent between both consoles as well. But I don't think it's bad enough to make it nessessary to change the sound effects in a game. BTW, z26 and the other emulators don't do the exact frequency of either console, so there might some marginal differences in the sound as well. Andrew: > When I have some extra time I will give that a try (but the little free > computer time I have seems to all be sucked up feeding bits to the woodgrain > box sitting next to my computer). If you don't do it, nobody else will. And then we all will have to live with visually imperfect versions of your games. ;-) > Is there any plan to port z26 to Windows. It's a great program (especially > the log feature) but as a DOS program, the performance under Windows XP is a > little disappointing. Weeelll, John and I have been thinking about that for quite a while now, and we even found someone who is willing to do all the Windows interfacing code, so that we can concentrate on porting the emulator core. But that person is currently very busy with his job, John is very busy with his move, and I can easily make up an excuse too, if I have to. ;-) So unless one of us eventually buys a new computer with XP on it and gets dissatisfied with the performance of z26 as well, it might still take quite a while before we'll be able to present a usable version of gz26 for XP. ;-) (Did anyone actually get that joke on the emulator/OS name? ;-) ) Manuel: > Ok, after I stopped paniking, I probably found a simple > & suitable solution. Can someone please test if the > attached NTSC bin produces a stable picture on a real > NTSC TV/VCS combination for me? I don't have a NTSC VCS, but I implemented the scanline display in z26, and while the old version was constantly switching between 261 and 262 lines, the new binary does a stable 262 lines. So I think it should work alright on a real system. One think I noticed though, when the game ends and the game jumps back to attract mode, it seems to be skipping a VSYNC and does a double-frame or something like that. Maybe you should have a look at that code again. > If I get that right, you want me to use the same line > numbers in both versions? > So it is supposed to work on a PAL TV, when ~70 lines > are just missing? This is correct. As Andrew has already mentioned, most PAL TVs should be able to display this nicely. The screen will be centered, so you'll get black bars above and below the picture. But that's what your normal PAL version should do anyway. BTW, it's exactly 50 lines that the PAL VCS screen is longer than the NTSC VCS screen. ;-) > Hm... in all my (Mega Drive / Super NES) experiences, a > difference between 50/60 doesn't make any difference, > neither in sound nor in gameplay. You should run the PAL version with the -5 switch in z26. Then you could see the difference. You are probably right, the gameplay doesn't really feel different. But maybe you could adjust the lenght of the notes for the song, to get the same playing speed as in the NTSC version? > My train of thought was like this: > > - The manual says do 38 PAL VBLANK lines. > - I wanted to keep 192 visible lines. > - Now I thought I've to add all the missing scannlines > to the overscan. This is basically correct, but if you do this, then the picture will start at the top of the TV screen. And since you are displaying less scanlines than you should for a normal PAL picture, you'll get all thos blank lines at the end of the display. This doesn't look too nice. Ciao, Eckhard Stolberg ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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