OSSC (Open Source Scan Converter) with an Amiga

[admiral]

Originally Posted by Retro-Nerd

Of course no lag at all. It's a Line 2x-5x device, not a video scaler which needs processing time.

Though the newer Retro-Tink 5x is a good development in the right direction, with the low lag video scaling. But it's expensive and with the current firmware quite unsuable for PAL content.

Retro-tink are not open hardware; They're not even in the same galaxy if you ask me.

[Retro-Nerd]

Yep, but what has that to do with the usuability of the device? Open Source = always better?

Retro-Tink 5x was the first of the new Nextgen game scaler. We get the OSSC Pro and PixelFX Morph scaler much later. (also very expensive i guess). We'll see then what they deliver. Fast Amiga resolution switching and Motion Adaptive deinterlacing on the Retro-Tink 5x works good, despite the PAL issues with the current firmware. Well, another (cheaper) alternative would be the GBS-Control AIO.

[rabidgerry]

Originally Posted by demolition

If your 19" monitor has a 1280x1024 resolution, then it is an exact 4x doubling to go from 320x256 (which is the normal low res PAL res) to 1280x1024. This means that Line4x mode might be the way to go with scaling on the monitor set to 1:1. Alternatively you can do Line2x scaling to 640x512 and then let the monitor to the upscaling to the panel. It will be a bit more blurry using the last choice but might still look better overall and will soften the scanlines as well if you are using those.

DVI Cable arrived yesterday, randomly the first issue I ran into was the remote stopped working. But I then read up that sometimes you need to re-program the remote, which I did. Then it took me an age trying to find DVI mode. But I eventually overcame that.

Now I'm at the point of trying to get a good display. So as you mentioned my monitor does support 1280 x 1024. The manual describes these two resolutions as optimal for the monitor.

1280 x 1024*1 @ 60 Hz to 75 Hz
1280 x 960*1 @ 60 Hz to 75 Hz

But I pretty much tried every resolution going and I was unable to get the workbench screen centred or full screen. Should I be able to achieve full screen using 1280 x 1024 on the ossc?

[MrClump]

Originally Posted by rabidgerry

Now I'm at the point of trying to get a good display. So as you mentioned my monitor does support 1280 x 1024. The manual describes these two resolutions as optimal for the monitor.

1280 x 1024*1 @ 60 Hz to 75 Hz
1280 x 960*1 @ 60 Hz to 75 Hz

But I pretty much tried every resolution going and I was unable to get the workbench screen centred or full screen. Should I be able to achieve full screen using 1280 x 1024 on the ossc?

Depending on how tolerant your monitor is of accepting a 50hz signal, then DBLPAL High Res No Flicker @ 640x512 (with no overscan) and Line 2x scaling on the OSSC will give you a pixel perfect, pin sharp, screen filling image.

You may need to put the VGAONLY driver into Devs:Monitors if your monitor won't sync.

Here is mine on a BenQ BL912.

https://imgur.com/J9SCtEP

[rabidgerry]

Originally Posted by MrClump

Depending on how tolerant your monitor is of accepting a 50hz signal, then DBLPAL High Res No Flicker @ 640x512 (with no overscan) and Line 2x scaling on the OSSC will give you a pixel perfect, pin sharp, screen filling image.

You may need to put the VGAONLY driver into Devs:Monitors if your monitor won't sync.

Here is mine on a BenQ BL912.

https://imgur.com/J9SCtEP

What can I say other than I'm jealous or your image of your monitor.

I think my monitor tolerates 50hz ok, the only useful setting I seem to be able to use is Pal Hi-Res. I don't know why.

I personally don't know where to start with the OSSC, do I go straight to the outputs menu and start seeing what setting works?

Like a lot of things in guides in Amiga land, the list of settings way back at the start of this thread don't really help, for a start the screen sizes are all completely different from those listed with my drivers defaults. So my Pal HiRes is not 724x284 it's like 640x200 or something. Then there is no mention about which output you should use, just those sample rates and what not. I tried these for a laugh and it just messed everything up and didn't dare go any further.

PAL:HiRes (724x284), PAL:LowRes (362x284):
240p/288p lineX3: Off
H. samplerate: 908
H. synclen: 60
H. active: 724
V. active: 284
H. backporch: 76
V. backporch: 25
Sampling phase: Adjust until you get stable and crisp picture.
Note: If V. active 284 does not work you may try 288 (PAL standard).

It looks as though from what I can see the size of you screen should determine the H.Active and V.Active settings, is that right?

So is I have something 640x400 I should change my H.active to 640 and V.active to 400? This isn't necessarily the setting I want to use it's just one of the very few that don't squash the screen or make it look weird.

I've attached my monitors spec. My monitor can actually take the native Amiga rgb signal but cuts of a bit of the screen at the bottom and is nowhere near as sharp as GBS-Control or this OSSC.

[MrClump]

Originally Posted by rabidgerry

I think my monitor tolerates 50hz ok, the only useful setting I seem to be able to use is Pal Hi-Res. I don't know why.

I personally don't know where to start with the OSSC, do I go straight to the outputs menu and start seeing what setting works?

If you're going to try DBLPAL then I don't think you need to do anything in the Outputs menu, although for low res you may want/need to.

Originally Posted by rabidgerry

Like a lot of things in guides in Amiga land, the list of settings way back at the start of this thread don't really help, for a start the screen sizes are all completely different from those listed with my drivers defaults.

It looks as though from what I can see the size of you screen should determine the H.Active and V.Active settings, is that right?

The settings at the start of the thread will work, but they're not going to give you a pixel perfect image on a 1280 x 1024 monitor. It took me a hell of a lot of fiddling about and cursing to figure it out.

Originally Posted by rabidgerry

So is I have something 640x400 I should change my H.active to 640 and V.active to 400? This isn't necessarily the setting I want to use it's just one of the very few that don't squash the screen or make it look weird.

I'm assuming you are going to aim for DBLPAL High Res No Flicker @ 640x512 as this is the resolution that should give you a pixel perfect image with your monitor.

The first thing you'll need to do is get your Amiga into the correct screen mode and resolution, make sure you have no overscan at all. So you resolution should be 640x512 and your text and graphics sizes in the overscan preferences should be the same. If you have any overscan you're either going to end up chopping off some of the image or not getting a pixel perfect result.

Set your workbench backdrop to be the tiny chequerboard pattern, you'll need this to dial in the settings. I would suggest having the VGAONLY monitor driver installed, as that'll make your Amiga output something closer to 50hz, so more likely to be tolerated by your monitor.

Make sure your OSSC is in Line 2x mode.

Your H.active & V.active need to be the same as the Amiga's resolution, so:

H.active - 640
V.active - 512

With both of those scaled to x2 that's where you'll get perfect integer scaling on your monitor.

Hopefully you should have some sort of image on screen, but it will likely look rubbish, so head to Adv. Timing under Sampling opt, 640x512 should be pre-selected.

With the fine chequerboard pattern on screen you will probably have vertical wavy bars on screen. If you move the H.samplerate you should see these get either larger or smaller depending on which way you move. The image will shift out of position as you're doing this, if it shifts too far you can move it back into the centre with H. Synclen and H.Backporch. I'm not sure what they both do as they both seem to do the same thing, move the image left and right!

You want to move the H.samplerate to expand distance between the bars, until you should eventually get to a point where there is a single bar, then one or two more increments will remove it completely. Push it any further and you you should see bars start to creep in again.

At this point you should have a very clear image, though likely out of position and with the phase all wrong which will show as horizontal wavy noise.

Adjust the horizontal position as previously, you should find you can completely fill the entire screen from left to right. Then do the same with a combination of the V.synclen and V.backporch to centre the image vertically. Once you have the image centred correctly your geometry should be perfect, as your Amiga display is being scaled perfectly for the screen.

Finally the phase, for this just move the setting until you reach a point where the wavy lines disappear. Then you're done, you should have pixel perfect 640x512!

The settings I ended with on my monitor were as follows:

H.samplerate 1040
H.synclen 160
H.backporch
H.active 640
V.synclen 3
V.backporch 11
V.active 512

You could just try entering those to see what you end up with and ignore the fiddling I talk about above!

Originally Posted by rabidgerry

I've attached my monitors spec. My monitor can actually take the native Amiga rgb signal but cuts of a bit of the screen at the bottom and is nowhere near as sharp as GBS-Control or this OSSC.

According to that your monitor does not support 50hz at 1280x1024, but then according to the specs neither does mine! It doesn't stop it syncing down to DBLPAL without VGAONLY at 47Hz though!

If you can get it to work on your monitor with VGAONLY loaded I would suggest then trying it without it. On my monitor I got better results without VGAONLY which was causing some weird distortion on the left hand side of the screen.

This is with the caveat I am no OSSC expert, I just managed to puzzle it out! Without using the OSSC my monitor also could not completely fill the screen, despite working at 15Khz, however with the OSSC I can, plus IMHO it gives a way cleaner image than natively connecting the Amiga to the same monitor with the same VGA cable.

The great news is that it's also possible to get a pixel perfect image at 1280x1024 for 320x256 low res mode for games too, as that is a perfect 4x multiple of the displays native resolution. You will lose any overscan though, so I have both the settings from this thread applied to 2x and then my own settings at 4x and swap between the two depending on whether or not the game is using any overscan. That's a whole other post though. :-)

[rabidgerry]

Originally Posted by MrClump

If you're going to try DBLPAL then I don't think you need to do anything in the Outputs menu, although for low res you may want/need to.




The settings at the start of the thread will work, but they're not going to give you a pixel perfect image on a 1280 x 1024 monitor. It took me a hell of a lot of fiddling about and cursing to figure it out.



I'm assuming you are going to aim for DBLPAL High Res No Flicker @ 640x512 as this is the resolution that should give you a pixel perfect image with your monitor.

The first thing you'll need to do is get your Amiga into the correct screen mode and resolution, make sure you have no overscan at all. So you resolution should be 640x512 and your text and graphics sizes in the overscan preferences should be the same. If you have any overscan you're either going to end up chopping off some of the image or not getting a pixel perfect result.

Set your workbench backdrop to be the tiny chequerboard pattern, you'll need this to dial in the settings. I would suggest having the VGAONLY monitor driver installed, as that'll make your Amiga output something closer to 50hz, so more likely to be tolerated by your monitor.

Make sure your OSSC is in Line 2x mode.

Your H.active & V.active need to be the same as the Amiga's resolution, so:

H.active - 640
V.active - 512

With both of those scaled to x2 that's where you'll get perfect integer scaling on your monitor.

Hopefully you should have some sort of image on screen, but it will likely look rubbish, so head to Adv. Timing under Sampling opt, 640x512 should be pre-selected.

With the fine chequerboard pattern on screen you will probably have vertical wavy bars on screen. If you move the H.samplerate you should see these get either larger or smaller depending on which way you move. The image will shift out of position as you're doing this, if it shifts too far you can move it back into the centre with H. Synclen and H.Backporch. I'm not sure what they both do as they both seem to do the same thing, move the image left and right!

You want to move the H.samplerate to expand distance between the bars, until you should eventually get to a point where there is a single bar, then one or two more increments will remove it completely. Push it any further and you you should see bars start to creep in again.

At this point you should have a very clear image, though likely out of position and with the phase all wrong which will show as horizontal wavy noise.

Adjust the horizontal position as previously, you should find you can completely fill the entire screen from left to right. Then do the same with a combination of the V.synclen and V.backporch to centre the image vertically. Once you have the image centred correctly your geometry should be perfect, as your Amiga display is being scaled perfectly for the screen.

Finally the phase, for this just move the setting until you reach a point where the wavy lines disappear. Then you're done, you should have pixel perfect 640x512!

The settings I ended with on my monitor were as follows:

H.samplerate 1040
H.synclen 160
H.backporch
H.active 640
V.synclen 3
V.backporch 11
V.active 512

You could just try entering those to see what you end up with and ignore the fiddling I talk about above!



According to that your monitor does not support 50hz at 1280x1024, but then according to the specs neither does mine! It doesn't stop it syncing down to DBLPAL without VGAONLY at 47Hz though!

If you can get it to work on your monitor with VGAONLY loaded I would suggest then trying it without it. On my monitor I got better results without VGAONLY which was causing some weird distortion on the left hand side of the screen.

This is with the caveat I am no OSSC expert, I just managed to puzzle it out! Without using the OSSC my monitor also could not completely fill the screen, despite working at 15Khz, however with the OSSC I can, plus IMHO it gives a way cleaner image than natively connecting the Amiga to the same monitor with the same VGA cable.

The great news is that it's also possible to get a pixel perfect image at 1280x1024 for 320x256 low res mode for games too, as that is a perfect 4x multiple of the displays native resolution. You will lose any overscan though, so I have both the settings from this thread applied to 2x and then my own settings at 4x and swap between the two depending on whether or not the game is using any overscan. That's a whole other post though. :-)

I don't think I have DBLpal installed on my Amiga. I will need to check.

I spent all evening messing around with the OSSC but had to give up. Got a multiscan option working and nearly full screen but it had a weird tear line near the title bar and the icons looked a little squashed.

Anyways, your massive amount of info is greatly appreciated, I will look for a DBLpal driver and follow your steps. Thank you for typing all that

[MrClump]

Originally Posted by rabidgerry

I don't think I have DBLpal installed on my Amiga. I will need to check.

I spent all evening messing around with the OSSC but had to give up. Got a multiscan option working and nearly full screen but it had a weird tear line near the title bar and the icons looked a little squashed.

Anyways, your massive amount of info is greatly appreciated, I will look for a DBLpal driver and follow your steps. Thank you for typing all that

I have maybe incorrectly assumed you have an AGA Amiga, if your Amiga is ECS or OCS then you won't have DBLPAL as an option.

[rabidgerry]

Originally Posted by MrClump

I have maybe incorrectly assumed you have an AGA Amiga, if your Amiga is ECS or OCS then you won't have DBLPAL as an option.

You assumed correctly don't worry I have A1200 with Apollo1260.

Hopefully can get the driver if Aminet.

[Shaytan]

Originally Posted by rabidgerry

You assumed correctly don't worry I have A1200 with Apollo1260.

Hopefully can get the driver if Aminet.

You can find the DblPAL Monitor and VGAOnly in your Storage/Monitors drawer.
Just copy them in Devs/Monitors and reboot, after that you'll have the screen modes available in ScreenMode Prefs.

[rabidgerry]

Originally Posted by Shaytan

You can find the DblPAL Monitor and VGAOnly in your Storage/Monitors drawer.
Just copy them in Devs/Monitors and reboot, after that you'll have the screen modes available in ScreenMode Prefs.

I don't think I have the DBLPal in my Classic WB 3.1 card. Just in case I don't I have copied the drivers from my OS 3.1.4.1 and I will put these on the CWB3.1

Will I need the VGA driver as well? Or should I try without first of all?

[Shaytan]

Try without first

[rabidgerry]

Starting to think my OSSC is faulty. Or I just don't understand how to select things.

So the DBLPal No flicker was in storage. I have installed this. When I selected it the screen went black.

The only way I could get image back up again was by going through the output settings and when I switched 480p/576p to passthru I got an image back on the screen, albeit shoved away over to the right hand side of the screen.

So since I could actually see the screen again I went and checked the overscan setting. This was already set to 640 x 512. It also would not let me adjust it at all. I figured it was ok though since it matched the DBLPal screen size.

So then I went to select Line2X mode, nothing happens from what I can see.

I then went to adv sample options and I see it is already set to 640 x 512 also. Not sure what I should do from this point whether or not just put in the

H.samplerate 1040
H.synclen 160
H.backporch
H.active 640
V.synclen 3
V.backporch 11
V.active 512

Also VGA only is already installed, does it need invoked from startup-sequence? It's just in monitors folder at the moment in devs.

[Shaytan]

Originally Posted by rabidgerry

Starting to think my OSSC is faulty. Or I just don't understand how to select things.

So the DBLPal No flicker was in storage. I have installed this. When I selected it the screen went black.

The only way I could get image back up again was by going through the output settings and when I switched 480p/576p to passthru I got an image back on the screen, albeit shoved away over to the right hand side of the screen.

So since I could actually see the screen again I went and checked the overscan setting. This was already set to 640 x 512. It also would not let me adjust it at all. I figured it was ok though since it matched the DBLPal screen size.

So then I went to select Line2X mode, nothing happens from what I can see.

I then went to adv sample options and I see it is already set to 640 x 512 also. Not sure what I should do from this point whether or not just put in the

H.samplerate 1040
H.synclen 160
H.backporch
H.active 640
V.synclen 3
V.backporch 11
V.active 512

Also VGA only is already installed, does it need invoked from startup-sequence? It's just in monitors folder at the moment in devs.

If I remember correctly, with DblPAL you have to set Allow upsample2x to ON in the Sampling Opt. on the OSSC.

I'm not at home to check right now but give it a try anyway

[rabidgerry]

Originally Posted by Shaytan

If I remember correctly, with DblPAL you have to set Allow upsample2x to ON in the Sampling Opt. on the OSSC.

I'm not at home to check right now but give it a try anyway

How do I know if a mode is selected or not? When I click on things nothing happens. Only when I move 480p/576p to passthru go I get picture. No other modes seem to work.

[Shaytan]

First thing first, is your OSSC firmware updated to the latest version (0.88)?

My advice is to read the wiki to better understand the various options available:

http://junkerhq.net/xrgb/index.php?title=OSSC

Besides the Advanced timing tweaker, most of the settings are shared between video modes, you can either use the onscreen feature or the display of the OSSC itself to navigate through the menu (useful when you don't have a video output).

This is what I would do in your situation:

-Set a known working workbench screen mode like PAL HiRes 640x256.
-Change the Allow upsample2x on the OSSC to ON.
-Set 480p/576p proc in Output opt. to 2X.
-Set Line2x mode to Generic 4:3
-Go back to ScreenMode Prefs and using the Test button try the DblPAL 640x512 no flicker mode and see if you get the test pattern working.

Let us know if you make any progress

[MrClump]

Originally Posted by Shaytan

If I remember correctly, with DblPAL you have to set Allow upsample2x to ON in the Sampling Opt. on the OSSC.

I'm not at home to check right now but give it a try anyway

I've got it set to off with DBLPAL, if I set it to on I still get an image but it get shifted over to the far right.

I don't really understand what that setting does!

[Shaytan]

Originally Posted by MrClump

I've got it set to off with DBLPAL, if I set it to on I still get an image but it get shifted over to the far right.

I don't really understand what that setting does!

I think it's used on some "strange" video modes which natively the OSSC could not handle correctly.

I remember that originally with Allow upsample2x set to OFF i couldn't get any picture using DblPAL.

I'm using a scart cable to connect to the OSSC btw, don't know if it make any difference.

[MrClump]

Originally Posted by rabidgerry

Starting to think my OSSC is faulty. Or I just don't understand how to select things.

I think it's unlikely your OSSC is faulty, as it seems to be basically working. When I've fiddled with it, a black screen seems to one the most common symptom of having a setting wrong.

When you get a black screen is that following some sort of on screen message such as "No sync", "Out of range" or similar, or more that the monitor is just displaying the colour black?

Originally Posted by rabidgerry

The only way I could get image back up again was by going through the output settings and when I switched 480p/576p to passthru I got an image back on the screen, albeit shoved away over to the right hand side of the screen.

This is actually good news! It tells you that your monitor does support 50Hz at least at 640x512, so may very well do at 1280x1024!

[MrClump]

Originally Posted by Shaytan

My advice is to read the wiki to better understand the various options available:
http://junkerhq.net/xrgb/index.php?title=OSSC

IMO that wiki is part of the problem for someone coming to the OSSC and trying to figure out how the hell to get the thing working. It's full of terms that assume you already have a good level of knowledge, and little explanation to help noobs.

I read it multiple times and just got more and more confused and have only managed to figure out the basic level of knowledge I've managed to gain from watching multiple how-to videos on YouTube instead.