Dreamcast PAL signal

[blinky56]

I am setting up my ntsc-u dreamcast (with gdemu) and ossc.

If I load a usa or japanese game, it works fine and the ossc lcd says:
525i
15.72kHz
59.90Hz

If I load a PAL game, the tv loses the picture and the ossc reports:
625i
15.61kHz
49.97Hz

What can I alter on the ossc to get my tv to sync the picture with this 625i signal?

[nmalinoski]

If you’re in a territory where PAL isn’t a thing, like the US, your display likely doesn’t support it at all, in which case, unless you instead want to track down a display that does handle PAL, you’re going to need an additional scaler in between your OSSC and display, like an Extron DSC 301 HD or other, that can do framerate conversion and scaling to bring the 50Hz signal up to 60Hz and scale the 576i/p frame to something your display can handle, like 480p/720p/1080p. The OSSC lacks the framebuffer necessary to perform these transformations, so it won’t be able to manipulate the signal on its own.

[blinky56]

Ah ok, thanks. I am running PAL games on my master system with a 50Hz switch and it works, but of course that isn’t a 625i signal. I guess my tv can’t handle it.

Do you think patching the GDIs to NTSC would work? I only have about 20 PAL titles to put on my gdemu.

[nmalinoski]

I am running PAL games on my master system with a 50Hz switch and it works…

I’m not sure what you mean; PAL games from the Dreamcast aren’t working, but PAL games from your Master System are?

…but of course that isn’t a 625i signal.

The OSSC displays total line counts, not visible line counts; so 625i is the same as 576i–576 visible lines, 625 total. Likewise, 525i is the same as 480i–480 visible lines, 525 total.

[BuckoA51]

Have you tried both passthrough and bob deinterlace modes? Are you certain the games you want to run don’t support 31khz (VGA) mode?

[blinky56]

@nmalinoski – yes, the 50hz PAL master system signal works fine, but the 50Hz dreamcast signal doesn’t

@BuckoA51 – GDMenu is set to force VGA so I am not sure why they are not running in that mode. I haven’t tried passthrough or deinterlace though, so I can try those. *Edit* Ok, I see I need a special cable to get the vga signal.

[blinky56]

Ok, passthrough and bob 2x/4x both don’t work with the PAL signal. I guess my tv doesn’t support it? I wonder if there are any settings I can adjust to try to get it to sync?

[blinky56]

How does audio work with Dreamcast and a VGA cable on AV3? Does one of the 3.5mm jacks work for input with it?

[Fed]

How is your Dreamcast hooked up to your OSSC ?
Quite a few Dreamcast PAL games offer 60hz output option and that has to be enabled in the game options or on game startup, can you share the list of of PAL games you want to play ?

[BuckoA51]

Yes you definitely want to be using 31khz VGA mode, don’t buy a VGA cable use one of the specially wired SCART cables that can do both modes, Retro Access and Retrogamingcables.co.uk both carry them.

[blinky56]

*Edit* Ok, nvm, I see the audio in for AV3 is the 3.5mm jack.

[blinky56]

I would buy one from Retro Access, but they are never available. Now they say to wait until June and can only order at 10am on a certain day.

Lol, that’s crazy.

[blinky56]

Ah, I bought one of the cheap retrobit VGA cables and everything works great via AV3 and 3.5mm audio jack, no matter if it is PAL or NTSC.

I’ll try to get a Retro Access VGA/Scart cable if I can.

Thanks for helping me get sorted out with this!

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