OSSC (Open Source Scan Converter) with an Amiga

[captain_zzap]

Originally Posted by Shaytan

Yes, you are absolutely correct.



Well, technically it's true, but the OSSC is perfectly capable of displaying DblPAL using a scart connection too and I'm sure of it because that's how my Amiga 1200 is connected.

Here is a quick example I did to help rabidgerry a while back.

Yes, I could be wrong. I think I read the thing about DBPal needing h/v sync somewhere, but I don't remember where and when. All I know is, I had always trouble with DBPal and Scart. Also, I only have ECS Amigas, no AGA.

[captain_zzap]

Originally Posted by rabidgerry

So obviously I have no clue about this stuff, but by your logic, if I wanted to use DBLPal I could use it in passthru mode with the NEC monitor (the one with DVI)?

Probably

Originally Posted by rabidgerry

This then leaves me with the question, how are others using DBLpal and x2 mode? Further back in this thread there is at least one guy using DBLpal for his workbench and he isn't using passthru.

A monitor can only display 2x, 3x, 4x, or 5x mode if it can handle the resulting resolution. My 1600x1200 could probably handle the 576 DBPal x 2 1152 Lines. Need to try.
In Theory, setting a higher line multiplier gives you a sharper image. In some modes I can set my monitor to not scale at all, which give me a bit of black borders, but absolute even pixels and a higher multiplier can reduce the black borders. But if a monitor can't handle higher resolutions, a higher multiplier won't work.

Originally Posted by rabidgerry

As you seem to know about DBLpal I don't suppose you know why it fucks up my screen with certain games even if it's in the monitor drawer but not selected? Earlier in this thread I was told it was mode promotion which I have disabled with my A1200. But DBLpal screws up micropose F1GP and Doom Attack to name but two games. If I take the screen mode out of the monitor drawer then this problem goes away. But it means I can bloody well use DBLpal!!

My question, why DBPal for games? Many games don't support DBPal. DBPal is resolution wise the same as Pal x2. So why bother other then flicker free Workbench in 640x512?

Originally Posted by rabidgerry

BTW nice photos, is that monitor 16:9 though?

It's a Dell 2001FP. Via DVI-D it eats 50Hz/60Hz no problem.

[MrClump]

Originally Posted by captain_zzap

Unless you scale the output of the Amiga, which the ossc afaik can’t do, you won’t get a pixel perfect fullscreen image on a 1024 line monitor.

I do

[rabidgerry]

Originally Posted by captain_zzap

Probably

My question, why DBPal for games? Many games don't support DBPal. DBPal is resolution wise the same as Pal x2. So why bother other then flicker free Workbench in 640x512?

Ask Shaytan and MrClump the same question and see what they say.



Still no one can answer the distorted picture I get with games when DBLpal resides in the monitor drawer even if not being used. It isn't the only monitor driver that does this either, but I can't remember the others that screw up some games from loading.

[MrClump]

Originally Posted by rabidgerry

Ask Shaytan and MrClump the same question and see what they say.

A flicker free, high res Workbench is precisely why I use DBLPAL; anything else just feels too cramped to me. I don't use it for games though (not even sure how I would), that's strictly plain old low-res PAL.

[captain_zzap]

Originally Posted by MrClump

I do

Nice.
How is your monitor connected? VGA? DVI-D?
Does your monitor crop the borders/ overscan?
Monitors can usually scale the image freely when attached via VGA, but not via DVI-D. Does yours allow manual scaling via DVI-D?
Are you using a tool for border blanking?
AGA? ECS?

[MrClump]

Originally Posted by captain_zzap

How is your monitor connected? VGA? DVI-D?

DVI-D

Originally Posted by captain_zzap

Does your monitor crop the borders/ overscan?

Nope. I'm running DBLPAL with no overscan, so the 640x512 output from the Amiga is a perfect integer of 1280x1024 from the OSSC at Line2x

Originally Posted by captain_zzap

Does yours allow manual scaling via DVI-D?

It doesn't but then it doesn't need to scale in DBLPAL or PAL anyway. I've also got low res PAL pixel perfect with Line4x which looks absolutely stunning so long as games aren't using any overscan.

Originally Posted by captain_zzap

Are you using a tool for border blanking?

I don't even know what one of those is. So I guess the answer is no!

Originally Posted by captain_zzap

AGA? ECS?

AGA

[MrClump]

Originally Posted by rabidgerry

Still no one can answer the distorted picture I get with games when DBLpal resides in the monitor drawer even if not being used. It isn't the only monitor driver that does this either, but I can't remember the others that screw up some games from loading.

Have you tried booting Workbench from a floppy with DBLPAL in the monitors drawer? It certainly doesn't do this for me, when running a game it drops down to PAL just fine.

[captain_zzap]

Originally Posted by MrClump

Nope. I'm running DBLPAL with no overscan, so the 640x512 output from the Amiga is a perfect integer of 1280x1024 from the OSSC at Line2x

As I said before, Amiga doesn’t output 512 lines, but 576 lines. And the OSSC can’t change that.

Originally Posted by MrClump

It doesn't but then it doesn't need to scale in DBLPAL or PAL anyway. I've also got low res PAL pixel perfect with Line4x which looks absolutely stunning so long as games aren't using any overscan.

I’m arguing that your monitor probably does scale. And that is great. It does that either by cropping black borders by itself, or by the information set via „adv. timing to reduce H/V“ https://videogameperfection.com/foru...an/#post-17059

I’m curious, do you ever have situations where the image isn’t centered/ sides are cut off? Some games have the screen area moved within the overscan area. Or what happens if you change the screen position overscan settings?
And I haven’t found your ossc config. Did you post it somewhere?

[MrClump]

Originally Posted by captain_zzap

As I said before, Amiga doesn’t output 512 lines, but 576 lines. And the OSSC can’t change that.

I’m arguing that your monitor probably does scale. And that is great. It does that either by cropping black borders by itself, or by the information set via „adv. timing to reduce H/V“ https://videogameperfection.com/foru...an/#post-17059

I’m curious, do you ever have situations where the image isn’t centered/ sides are cut off? Some games have the screen area moved within the overscan area. Or what happens if you change the screen position overscan settings?
And I haven’t found your ossc config. Did you post it somewhere?

I'm pretty certain it isn't. In both DBLPAL and PAL the monitor says it is receiving a 1280 x 1024 image from the OSSC and doesn't display any of the warnings it normally does when it receives anything other than it's native resolution. If it is scaling then this crusty old monitor has got one of the best scaling algorithms out there, as there is absolutely zero evidence of it on screen. When you see it in the flesh it almost looks like an emulator, it's that perfect.

Yes a few games that either aren't centred or use overscan don't display quite right, in that situation I have a Line2x profile I use which then does rely on the monitor scaling the image. If I move the Workbench screen position using the overscan settings it moves partially off the edge of the display.

My DBLPAL config is posted earlier in this thread.

[MrClump]

I think I see what you mean now. Yes I am using H.active 640 and V.active 512, but my understanding is that's not making the monitor scale, but making the OSSC create a 640x512 frame and ignore everything else outside that.

[MrClump]

For ease of reference my config for DBLPAL is:

Line 4x
Allow upsample 2x = ON

H.samplerate 1040
H.synclen 255
H.backporch 194
H.active 640
V.synclen 1
V.backporch 34
V.active 512

My PAL config is identical, other than H.active and V.active are 320 & 256 respectively and I use Line4x. I should note this doesn't work properly with PAL High Res though, only Low Res.

[captain_zzap]

Originally Posted by MrClump

I think I see what you mean now. Yes I am using H.active 640 and V.active 512, but my understanding is that's not making the monitor scale, but making the OSSC create a 640x512 frame and ignore everything else outside that.

The ossc still sends the whole frame, but tells the monitor to crop the border. After cropping, scaling with visible image degradation is obviously not happening.
I guess the problem starts, when a monitor doesn’t do this cropping step right or isn’t set right.

[MrClump]

Originally Posted by captain_zzap

The ossc still sends the whole frame, but tells the monitor to crop the border. After cropping, scaling with visible image degradation is obviously not happening.
I guess the problem starts, when a monitor doesn’t do this cropping step right or isn’t set right.

I see what you mean now, I just went back and re-read Marqs' comment and now I understand. Because my H & V active are an integer of the monitor's native resolution it can perfectly scale it.

[MrClump]

@rabidgerry I've just ordered a BenQ BL902 from eBay to see how it works as a spare monitor. It's a 5:4 1280 x 1024 19" model with DVI-D input and I've got high hopes for it working well with the OSSC. They're also plentiful and dirt cheap! I'll report how well it works when it arrives next week.

[rabidgerry]

Originally Posted by MrClump

A flicker free, high res Workbench is precisely why I use DBLPAL; anything else just feels too cramped to me. I don't use it for games though (not even sure how I would), that's strictly plain old low-res PAL.

Yeah so I want the same as you.

However to refer back to @captain_zzap and his question

My question, why DBPal for games? Many games don't support DBPal. DBPal is resolution wise the same as Pal x2. So why bother other then flicker free Workbench in 640x512?

So he wants to know how I intend to play games with DBLpal.

Well how do you play games @MrClump?

You have a separate setting on OSSC right? To switch for when games load? Or Did I imagine this?

In a nut shell DBLpal wont be used for games when they load right? Or am I trippin here?

Originally Posted by MrClump

@rabidgerry I've just ordered a BenQ BL902 from eBay to see how it works as a spare monitor. It's a 5:4 1280 x 1024 19" model with DVI-D input and I've got high hopes for it working well with the OSSC. They're also plentiful and dirt cheap! I'll report how well it works when it arrives next week.

Isn't that one of the monitors that can do native Amiga though?

Please do let me know how you get on.

I have been eyeing up a ViewSonic that does have DVI-D (as the one I bought this week only has VGA). I like the ViewSonic as pretty much all of them can sync down to Amiga Pal and that is another shit show I am keen to avoid, buying a monitor than cannot accept just below 50hz.

Mind you I guess that NEC I have accepts Amiga Pal as well, but I can't get a picture using DBLpal.

It's all rather complicated

[Jope]

HDMI monitors have a higher chance of syncing down to 49.92Hz. DVI only monitors are a bit hit and miss, many have a lower limit of 60Hz, unfortunately.

[Shaytan]

Originally Posted by rabidgerry

Well how do you play games @MrClump?

You have a separate setting on OSSC right? To switch for when games load? Or Did I imagine this?

In a nut shell DBLpal wont be used for games when they load right? Or am I trippin here?

You don't need a separate profile for PAL, the OSSC identify PAL as 288p and DblPAL as 576p, you can have multiple settings in the same profile as long as the vertical resolution is different.

I think MrClump has a different profile with one change (line2x) just for some games that don't display correctly using line4x for 288p, everything else is handled by one single profile.

[rabidgerry]

Originally Posted by Shaytan

You don't need a separate profile for PAL, the OSSC identify PAL as 288p and DblPAL as 576p, you can have multiple settings in the same profile as long as the vertical resolution is different.

Yes, yes I remember now, I just setup my OSSC 288p section then how I like so when games play they display correctly.

Now that was not for my benefit, that was for captain_zzap who asked me.

So yeah this is how I intend to use DBLpal and be able to play games, like Shaytan explains above!


@Jope you are using a 16:9 modern hdmi monitor then? I could myself I suppose but prefer to find the right 5:4 monitor. I ran OSSC into a 32" Sharp TV before than that worked nice but floating display surrounded by black city was the order of the day.

@MrClump I have not tried a game from floppy, surely though it works because it hasn't loaded DBLpal yet as it has booted from floppy? So you put in the floppy and the game loads as normal because your HD hasn't loaded in the background. Has to be some fix for the stupid distorting of games. Bare in mind it isn't all games. F1GP and Doom Attack and Blood being 3 of them.

[Jope]

Yeps, these days it's very often FHD or 2k 16:9 with black stripes on the sides.

I had some DVI monitors that synced down, but the image quality / viewing angles in those are so terrible these days.