Hydro Thunder for Dreamcast

[mario64]

I’m having issues with Hydro Thunder for Dreamcast. My version is VGA compatible and works fine with the Framemeister. With OSSC, however, it gets to the Sega logo then my TV just goes “no signal”. The sync light flickers from green to red and I can intermittently hear bits of audio but no video at all. My other DC games work fine. I’m connecting to OSSC via Toro box set to 480p. Both pass-through and 2x have this problem. Are there specific settings I need to use for this game? Thanks

[BlueStinger]

Apparently, you’re not the only who has issue with this game : https://dreamcast-talk.com/forum/viewtopic.php?t=4088
It appears that there is another version of this game called “All stars” that would work in VGA mode. Have you tried to run it in RGB mode ?

[mario64]

As noted in my original post, my version is VGA compatible and works fine with the Framemeister. Only OSSC has issues

[BlueStinger]

Ooooh that’s right… At least I tried ^_^ Good luck with that mate and if you find a solution, make sure to post it here, it might be helpful for people in the future.

It’s from Beharbros’ website, maybe it’s just a sync issue, have you tried those ? (sorry if it’s a stupid question, we never know)

MULTI VIDEO SYNC SYSTEM
Both CSYNC and H&V SYNC modes supported
Euro Scart connector can output RGBS (CSYNC) (480i+480p for the XRGB)
VGA connector can output RGBS or RGBHV. It’s selectable by a push button.

[mario64]

Thanks yeah. I figure there are probably OSSC settings to fix it but I don’t know them all well enough to figure it out.

[BuckoA51]

Are you using SCART or VGA out of your Toro?

[mario64]

SCART

[BlueStinger]

I’m not sure SCART can output 480p with the Dreamcast. Technically, Scart can go as high as 1080p (according to wikipedia) but I think YOU HAVE to use a VGA cable to output 480p when it comes to Dreamcast. Unless you have RGBHV through the SCART but I doubt it.

Hmmmmm this comes from Beharbros : ” Euro Scart connector for connecting to your TV or upscaler. Supports 480i & 480p.”

So maybe OSSC can’t do RGBVH through SCART. On my remote control, here are the sync options :
RGBS
RGsB
YPbPr

So, I think OSSC doesn’t accept RGBVH through SCART. Wait for a more knowledgeable person to confirm, but it seems to me that the issue comes from here.

[mario64]

480p SCART works perfectly fine via Toro box. Only Hydro Thunder has issues

[BlueStinger]

Oh no, I did it again, haven’t I… I always forget one important component of the issue and give irrelevant answers… Sorry mate.
This link did not help you ? https://dreamcast-talk.com/forum/viewtopic.php?t=4088
Apparently, some versions of this game (and other Midway games) won’t run in VGA mode.

[mario64]

Oh no problem at all. Thanks for trying 🙂

[BuckoA51]

What does OSSCs LCD say while this is all going on?

[nmalinoski]

@BlueStinger

I’m not sure SCART can output 480p with the Dreamcast. Technically, Scart can go as high as 1080p (according to wikipedia) but I think YOU HAVE to use a VGA cable to output 480p when it comes to Dreamcast. Unless you have RGBHV through the SCART but I doubt it.
…
So maybe OSSC can’t do RGBVH through SCART.
…
So, I think OSSC doesn’t accept RGBVH through SCART. Wait for a more knowledgeable person to confirm, but it seems to me that the issue comes from here.

Normal SCART cables made for the Dreamcast are wired to make the console output in 15kHz (240p/288p/480i/576i) RGBS, and VGA boxes and cables are wired to make the console output in 31kHz (480p) RGBHV; so, normally, the Dreamcast can’t output 480p over SCART, because, by triggering 480p mode, you change the sync output from composite to separate, which is fundamentally incompatible with SCART.

That gets into the other part of your post, to which I can say no, the OSSC doesn’t accept RGBHV over SCART, because SCART was designed for composite sync (RGBS, YC, CVBS), so it doesn’t have the requisite wiring to accommodate a second sync line. Technically you could just send it over one of the otherwise unused wires, but no standards-abiding SCART device will be able to understand the signal.

Also, on this note, while SCART cables are indeed technically capable of transporting up to 1080p, as well as other signal types, like YPbPr, you need to make sure your destination devices support what you’re feeding them. The OSSC can absolutely handle 1080p over its SCART input, but that doesn’t mean all of your SCART-compliant devices will be able to understand or be compatible with 480p+.

As for the Toro, it’s not actually getting RGBS out of the console; what it’s doing is receiving RGBHV from the console and running the sync signals through a sync combiner to get RGBS, which it outputs on the SCART port. The OSSC can handle 480p on its SCART input, so this arrangement works (and arguably works better than using a VGA cable and AV3, because AV1 has better LPF support).

[mario64]

@BuckoA51 The only change in the LCD is the sync light changing back and forth from red to green. It has been reported that the VGA compatible re-release of this game constantly changes from 523 to 524 lines of output which is obviously wrong. Framemeister handles it no issue though

[BlueStinger]

Sorry for the cross discussion, guys. I’ll just address a quick point and I’m leaving you alone !

@nmalinoski “works better than using a VGA cable and AV3, because AV1 has better LPF support” Oh man, I wish I knew that just 2 days ago ! I’ve just ordered a Kuro last Thursday! That will be good enough and my SCART is already used anyway but I wish I knew that sooner.

Sync combiner… Makes sense, didn’t occurred to me.

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