OSSC (Open Source Scan Converter) with an Amiga

[Jope]

I understand you're going for DBLPAL to get any kind of image on screen, but as you noticed, this is mainly useless for games.

If you want it all, you really need to have a monitor that can display the Amiga's PAL vertical refresh, or a scaler which does frame rate conversion. You will lose smooth scrolling with frame rate conversion.

So in the end, it really is down to making a few choices. Are smooth scrollers important? Are you willing to spend time searching for a suitable monitor? If no to either, then the OSSC was not the tool for this job.

[Gryfon]

Slightly off-topic...sorry. I was planning to buy an OSSC from videgameperfection.com who I read is a recommended reseller, but between me saving up over a few months and going to buy one Brexit has reared its' ugly head and VGP no longer ship from Ireland to the UK. There isn't even an option for me to pay extra for delivery / VAT / import-bollocks tax to get one - annoyingly. I don't want to support the Kaico/knock-offs effort buy getting one on EBay, but I cannot find any other UK-based seller. Does anyone know of someone in the UK who is sells and supports the OSSC in the same way VGP do?

[rabidgerry]

Originally Posted by Jope

I understand you're going for DBLPAL to get any kind of image on screen, but as you noticed, this is mainly useless for games.

If you want it all, you really need to have a monitor that can display the Amiga's PAL vertical refresh, or a scaler which does frame rate conversion. You will lose smooth scrolling with frame rate conversion.

So in the end, it really is down to making a few choices. Are smooth scrollers important? Are you willing to spend time searching for a suitable monitor? If no to either, then the OSSC was not the tool for this job.

I get what you are saying. And have also thought about perhaps this is not the tool for me.

So for an OSSC you need a monitor that can cope with 50hz basically?
Just out of curiosity, I have often wondered how the Amiga NTSC mode works, what exactly does this do and what is it useful for? If it is used does it out put everything at 60hz or would it change depending on the WB screenmode or game?



Ok so I guess I'm going to try and find a suitable monitor even though I thought my NEC was suitable. I don't want a wide screen monitor though so I am trying to stick with 5:4.

The Samsung I had I was unable to try as it only had a VGA connection.

I have spotted an EIZO FlexScan S1921 monitor I might try, perhaps an excessive experiment but may be I can get rid of the growing collection of monitors if I find that one suitable. Again like my Nec it says it requires 50/60hz. Is this still a gamble?

[rabidgerry]

Upon further investigation, it seems there isn't a lot of choice out there for monitors of a 5:4 ratio and HDMI input. Seems you either have VGA, VGA and DVI-D or VGA, DVI-D and Display Port.

[Jope]

Originally Posted by rabidgerry

So for an OSSC you need a monitor that can cope with 50hz basically?

For normal Amiga PAL screens, you actually need 49.92Hz. This is never advertised with any monitor, either they sync or they do not. The 15kHz list linked to elsewhere on this sub forum is not that useful for OSSC use unfortunately, as it focuses more on 15kHz via the VGA port without any scaler in between.

Just out of curiosity, I have often wondered how the Amiga NTSC mode works, what exactly does this do and what is it useful for? If it is used does it out put everything at 60hz or would it change depending on the WB screenmode or game?

It is a 60Hz 15kHz display mode. If your Amiga is set in hardware to boot up in this mode, it is an NTSC Amiga so to say. In this case, floppy booter games will also often run in NTSC mode.

Otherwise it's just available so you can choose to run your Workbench in this mode and for example with WHDLoad, you can run some games in 60Hz too. Not all are 60Hz compatible, some glitch out, some refuse to work, some will work but have the graphics cut off at the bottom of the screen.

But it is down to the hardware. Each Amiga is either 50Hz or 60Hz depending on hardware settings and/or model of Agnus. The hardware setting is what hardware banging software looks at and what you see in Workbench is only for nice system compliant software to make use of.

[rabidgerry]

Thanks for this information btw much appreciated

Ok so I'm taking a stab in the dark then hoping a monitor I choose can do 49.92Hz.

Great! Almost begs the question, why hasn't anyone ever started a list for monitors that can do 49.92Hz?

Oh well lets see how I get on. Lots of 5:4 choice but not knowing what is they can deal with 49.92Hz is a total nightmare.

[Jope]

It is, believe me. I have a pile of cheap non-49.92Hz monitors I haven't had the heart to throw out. :-)

Some sync but do an internal framerate conversion so that scrolling is choppy. Many just don't sync.

Things got a bit nicer in the 2010s. When monitors with both VGA and HDMI started coming out, surprisingly it became more common to see 50Hz and 49.92Hz support via both VGA and HDMI. These are of course widescreen and often the Amiga's/OSSC's display modes are such that the monitor's firmware will disable your ability to switch it to 4:3 mode and you get a stretched image. :-/

[rabidgerry]

Interesting I can get multiscan to fill my screen and then play IK+ which has the 49.92Hz but when I go to play F1GP I get a black screen at like 53hz??

[MrClump]

Originally Posted by rabidgerry

Interesting I can get multiscan to fill my screen and then play IK+ which has the 49.92Hz but when I go to play F1GP I get a black screen at like 53hz??

I am very curious about this NEC monitor. I just spotted one on eBay for £20, so I've bought it! Watch this space in a week or so.....

[MrClump]

Originally Posted by Gryfon

Slightly off-topic...sorry. I was planning to buy an OSSC from videgameperfection.com who I read is a recommended reseller, but between me saving up over a few months and going to buy one Brexit has reared its' ugly head and VGP no longer ship from Ireland to the UK. There isn't even an option for me to pay extra for delivery / VAT / import-bollocks tax to get one - annoyingly. I don't want to support the Kaico/knock-offs effort buy getting one on EBay, but I cannot find any other UK-based seller. Does anyone know of someone in the UK who is sells and supports the OSSC in the same way VGP do?

Not the UK based seller you were asking for, but I bought mine from Aliexpress from this seller around six months ago and it's been absolutely perfect. It was delivered in around two weeks.

https://www.aliexpress.com/item/1005001901294325.html

[jbenam]

Originally Posted by MrClump

Not the UK based seller you were asking for, but I bought mine from Aliexpress from this seller around six months ago and it's been absolutely perfect. It was delivered in around two weeks.

https://www.aliexpress.com/item/1005001901294325.html

I suppose Gryfon's point was that VGP donates to marqs85 every X units sold, while all those resellers don't, and I guess he wants to support the original developer with his purchase.

I have a Kaico unit myself and it has always worked flawlessly. I use with mainly with my NES (RGB-modded) and SNES these days and the picture is top notch.

Sure, you have to fiddle with settings a bit, but it's totally worth it.

I should set it up with my A500 and see if I do get the same issues others are seeing with their Amigas...

[rabidgerry]

There has been a bit of a development, leading me to believe the problem may lie on my Amiga software/hardware compatibility.

So I was complaining that when I used a screen mode that did work and got me a fullscreen for my work bench and everything seemed good, that I had issues with games, one being F1GP and other being IK+.

IK+ was shunted off to the right and F1GP was a black screen.

Well, I went back to my original setup (something I appreciate a little more now) and I thought everything would be fine. What do you know? F1GP loaded but was garbled and distorted and FUCKED UP! IK+ was shunted to the right.

I tried various things including an older backup of the same drive on another card and things worked as normal, I even tried copying the monitors folder from that drive over to the original drive I was using with the OSSC. Anyways, the same problems existed.

Basically no matter what I tried certain things were not right.

I got rid of DBLPal from my Monitors folder and put it back in storage. What do you know?

Problems gone.

Now who wants to have a crack at answering that one?

Just to be clear, I was NOT even using the DBLPal driver at the time or some of the other times I had these issues because I would get a black screen and it was unusable so it was merely sitting in the folder unused. Yet removing the driver suddenly cured issues. What the hell is that about?

The only thing I can throw out there with my lack of knowledge is that perhaps my Apollo 1260 doesn't like the DBLPal driver?? I dunno

Anyways, I suspect my monitor is fine after all and it's actually my Amiga for some reason.

Originally Posted by MrClump

I am very curious about this NEC monitor. I just spotted one on eBay for £20, so I've bought it! Watch this space in a week or so.....

Dammit that was cheaper than what I got it for It's not a bad monitor if I am honest.

[Jope]

3.1 can do mode promotion on an AGA machine when you have the DBLPAL monitor enabled. You don't need to have a DBLPAL screenmode selected, it's enough to have mode promotion on and DBLPAL loaded.

https://commodore.bombjack.org/amiga..._Workbench.pdf
Pages 110, 145 onwards, specifically 160

Depending on how the game you're running opens its screen, the OS may promote it.

You never mentioned whether you're running these with WHDLoad or not.

[rabidgerry]

Originally Posted by Jope

3.1 can do mode promotion on an AGA machine when you have the DBLPAL monitor enabled. You don't need to have a DBLPAL screenmode selected, it's enough to have mode promotion on and DBLPAL loaded.

https://commodore.bombjack.org/amiga..._Workbench.pdf
Pages 110, 145 onwards, specifically 160

Depending on how the game you're running opens its screen, the OS may promote it.

You never mentioned whether you're running these with WHDLoad or not.

Oh yes sorry I forgot, IK+ was a WHDload example where as Micropose F1GP is a HD install.

I'll need to read what that is about as I don't really understand. Some sort of automatic use of the driver without selection? Just needs to be in the folder?

Thanks again for the info btw.

[Grazey]

Originally Posted by Gryfon

Slightly off-topic...sorry. I was planning to buy an OSSC from videgameperfection.com who I read is a recommended reseller, but between me saving up over a few months and going to buy one Brexit has reared its' ugly head and VGP no longer ship from Ireland to the UK. There isn't even an option for me to pay extra for delivery / VAT / import-bollocks tax to get one - annoyingly. I don't want to support the Kaico/knock-offs effort buy getting one on EBay, but I cannot find any other UK-based seller. Does anyone know of someone in the UK who is sells and supports the OSSC in the same way VGP do?

I was in the same boat regarding shipping to the UK Although they do sell to Northern Ireland, a joke! Anyway enough polictics. In the end I bought my OSSC from Kaico for £130, I didn't realise there was issue with them? Are they a bit dodgy?!


Cheers
Grazey

[rabidgerry]

After a read of the manual then I can see that DBLPal was causing me issues so that explains that. Weird how I can't use the driver and how it had effects on F1GP.

Originally Posted by Grazey

I was in the same boat regarding shipping to the UK Although they do sell to Northern Ireland, a joke! Anyway enough polictics. In the end I bought my OSSC from Kaico for £130, I didn't realise there was issue with them? Are they a bit dodgy?!


Cheers
Grazey

No issue, but it seems it's a tool that requires very specific monitor spec.

Well they sell to Northern Ireland because we are still in the European Union’s customs union and Republic of Ireland is in the EU.

They are bound to sell to UK though, just more expensive after customs probably.

[Shaytan]

Originally Posted by rabidgerry

After a read of the manual then I can see that DBLPal was causing me issues so that explains that. Weird how I can't use the driver and how it had effects on F1GP.

Have you tried the WHDLoad version of F1GP?

Anyway I quote myself

Originally Posted by Shaytan

Before concentrating with the DblPAL screen mode be sure to have the standard PAL resolutions sorted first, it will give you more confidence with the various OSSC options.

IMHO you're focusing too much on a resolution which is mostly just used for the workbench while your effort should be better spent in getting the standard PAL resolution to work properly with a smooth 50hz scrolling.

[Gryfon]

Originally Posted by Grazey

I was in the same boat regarding shipping to the UK Although they do sell to Northern Ireland, a joke! Anyway enough polictics. In the end I bought my OSSC from Kaico for £130, I didn't realise there was issue with them? Are they a bit dodgy?!


Cheers
Grazey

Not "dodgy" per-se - I understood that VGP was the preferred reseller and supported the original developer where Kaico do not. I like to support people when I can and it feels a little wrong to save a couple of pennies whilst Kaico benefit.

@MrClump Thank you for the recommendation - that is certainly a lot cheaper than most of the quotes I've found.

@jbenam Correct!
I bought a Retrotink from VGP previously which they shipped from Ireland last year, so whilst I appreciate the new import/duties issues people have to face shipping to England, it doesn't take away the fact that it is -supremely- annoying when they simply stop selling here. Others have made agreements with local resellers to sell there stuff here - https://retrolemon.co.uk/ for example sell Lotharek products for 8-bit Atari machines at the same price as they sell from Poland, without the nasty delivery and import duties. I would happily pay extra to ship here.

Anyhoo...way off topic....

[Jope]

Originally Posted by rabidgerry

Oh yes sorry I forgot, IK+ was a WHDload example where as Micropose F1GP is a HD install.

Ok, then F1GP was definitely not DBLPAL compatible, and it probably had been promoted to DBLPAL by the OS. Stuff running under WHDLoad will not be promoted ever, they will open on a normal PAL/NTSC screen every time, depending on your WHDLoad settings.

I'll need to read what that is about as I don't really understand. Some sort of automatic use of the driver without selection? Just needs to be in the folder?

Yes. If you have DBLPAL in the Devs/Monitors directory, the systems enables these monitors automatically.

When a program opens a new screen, the contents of this directory are what are avaialble to the software. Old software only knows of PAL or NTSC, more modern software can actually choose what they want.

Now AmigaOS3.1 has a feature where if you have a PAL Amiga with DBLPAL loaded, it can bump PAL screens into DBLPAL screens automatically using a feature called mode promotion.

I am working under the assumption that you are aware of what an intuition screen means when you use the Amiga. The workbench screen is one, but you can have multiple in a stack. Basically every program ought to open on its own screen so that you don't clutter your workbench screen with windows.

[Total Eclipse]

Originally Posted by Gryfon

Not "dodgy" per-se - I understood that VGP was the preferred reseller and supported the original developer where Kaico do not. I like to support people when I can and it feels a little wrong to save a couple of pennies whilst Kaico benefit.

Kaiko are listed as an approved seller nowadays, just as VGP are.