Automatic scaling issues

[mark_k]

I tested WinUAE 2.4.0b20 in Windows XP SP3 (VirtualBox VM) and noticed some issues with automatic scaling. This doesn't seem specific to the beta as 2.3.3 showed pretty much the same issues.

1680x1050 Windows desktop. Aspect Ratio Correction disabled.

Emulated Amiga NTSC with ECS Agnus running OS 3.1, PAL high-res laced Workbench screen, 640x560 pixels (I increased vertical text overscan). Using a checkerboard WB background pattern which shows up any scaling artifacts clearly.

The first two issues below I saw in Windows XP in VirtualBox, but not when running under Wine. Could this be due to a bug in the VirtualBox graphics driver? Can anyone reproduce on native Windows?

1. With Null filter, No scaling, the Amiga display is shrunk vertically by 31 or 32 rows. Rows of pixels are missing regularly all the way down the screen. Changing the filter to none, the Workbench is shown 1:1 without missing pixels.

2. With Null filter again and enabling Integer scaling, the display is clearly being scaled by a non-integer amount.

The next issues happen for me in both XP/VirtualBox and Wine.

3. Enable Automatic scaling in Filter Settings. The Workbench display "jitters". The effect is hard to describe, but it's as if parts are jumping up and down. If I run a program which opens a non-laced screen the problem stops, until I drag the new screen down revealing the Workbench behind, then the whole screen starts jittering again. The problem only seems to happen when the display is interlaced. (Dragging a non-laced screen down to reveal another non-laced screen there is no jittering.)

If I change PAL overscan back to the default (so 640x512 WB), the screen does not jitter.

4. This applies to both the 640x560 and normal 640x512 screen: With the WB screen the only one open, dragging it down causes it to expand vertically, with the top of the screen remaining at the top of the emulation window, until the display is fully-expanded, after which it does move down as you continue dragging.

5. If instead of Automatic scaling I select Automatic resize in Filter Settings, when the screen would be jittering there's just a black screen and shortly after that WinUAE crashes. Dump file for that attached if it's any help.

[Toni Wilen]

1-2: logs needed. D3D and DirectDraw? Usually it is VM problem, they really seem to hate dynamic surfaces/textures (whole big surface is updated 50fps using the CPU).

3: probably a bug.

4: it is normal, autoscale only calculates (and sometimes guesses) where display starts and ends using custom chipset register values. It does not know (and can't know) nothing about dragging, scrolling etc..

[Amiga1992]

I have been trying to get a nice picturr with the filters too. I tried for a scale that would exactly double the resolution, but you can easily see in wb patterns that the pixels are deformed. I perhaps am not making it right, first time i mess with the shaders, but i's like to get an image that maintains pixel proportion but is as big as my display allows.

[Toni Wilen]

Originally Posted by Akira

I have been trying to get a nice picturr with the filters too. I tried for a scale that would exactly double the resolution, but you can easily see in wb patterns that the pixels are deformed. I perhaps am not making it right, first time i mess with the shaders, but i's like to get an image that maintains pixel proportion but is as big as my display allows.

DirectDraw or D3D? Note that DD always seems to enable some filtering. D3D only if bilinear option is set.

Integer scaling option or 1x/2x.. select boxes should always enable pixel perfect mapping without blurring (unless DirectDraw..)

(Not really on-topic..)

[mark_k]

Originally Posted by Toni Wilen

1-2: logs needed. D3D and DirectDraw? Usually it is VM problem, they really seem to hate dynamic surfaces/textures (whole big surface is updated 50fps using the CPU).

Logs attached. The missing lines/slightly squashed effect happens in both Direct3D and DirectDraw modes. (DirectDraw performance in VirtualBox is really bad, I get about 20fps vs 50 when using Direct3D mode, both with null filter. Performance is best in VirtualBox using DirectDraw with no filter.)

Strangely, when testing again I couldn't reproduce the "integer scaling not scaling by integer amount" issue in VirtualBox.

[Amiga1992]

Originally Posted by Toni Wilen

(Not really on-topic..)

Sorry about going off topic, I'll make my own thread. I have no problem with blurring, rather with pixels being not square

[mark_k]

An update on one of the points I mentioned before...

Originally Posted by mark_k

The first two issues below I saw in Windows XP in VirtualBox, but not when running under Wine. Could this be due to a bug in the VirtualBox graphics driver? Can anyone reproduce on native Windows?

1. With Null filter, No scaling, the Amiga display is shrunk vertically by 31 or 32 rows. Rows of pixels are missing regularly all the way down the screen. Changing the filter to none, the Workbench is shown 1:1 without missing pixels.

Testing WinUAE today under Wine, I'm seeing that missing-lines issue with filter none or Null, No scaling, graphics API Direct3D. (There are no missing lines with DirectDraw.)

When I set scaling to Integer scaling (still with Direct3D gfx API), there are no missing lines.

[Toni Wilen]

Originally Posted by mark_k

3. Enable Automatic scaling in Filter Settings. The Workbench display "jitters". The effect is hard to describe, but it's as if parts are jumping up and down. If I run a program which opens a non-laced screen the problem stops, until I drag the new screen down revealing the Workbench behind, then the whole screen starts jittering again. The problem only seems to happen when the display is interlaced. (Dragging a non-laced screen down to reveal another non-laced screen there is no jittering.)

If I change PAL overscan back to the default (so 640x512 WB), the screen does not jitter.

I can't duplicate this just by using 640x560 overscan. What are exact overscan values that causes the autoscale "jitter"?

[mark_k]

Attached is an archive of prefs settings for overscan, screenmode and wbpattern. (Note: due to the EAB forum only accepting certain file extensions, I added a .zip suffix to the filename. You'll need to remove that before unpacking the gzipped tar archive.)

Take a Workbench 3.1 disk. Copy the prefs files from the attached archive into Prefs/Env-Archive/Sys, then boot from the disk. Hopefully that should be sufficient to show the problem. I see the jittering when Workbench loads. If it's relevant the emulation settings I used were PAL, ECS Agnus, immediate blitter, A2000 chipset extra.

[Toni Wilen]

Screen is still stable.

[mark_k]

I've confirmed the jittering effect on native Windows Vista too. It happens with both WinUAE 2.3.3 and 2.4.0b21. Can you see the problem using the attached settings file?

Since it's not allowed to attach a modified Workbench disk here, I've created a patch file so you can recreate the disk image I'm using for testing. Starting with a Workbench 3.1 ADF file (MD5: 1fb61921fcaebe926d78257ff658431b), you can use GPatch to create the modified WB3.1 disk.

Get GPatch from Aminet: http://aminet.net/util/misc/gpatch.lha (Amiga binaries), http://aminet.net/misc/emu/gpatchix.tgz (Unix/Linux binaries), or http://aminet.net/misc/emu/gpatchwin.zip (Windows binaries).

[Toni Wilen]

Thanks.

I thought interlace always started from even line but it wasn't true (for some reason I couldn't duplicate this by testing different overscan settings).

Now autoscale only checks long fields if interlace is active.

[mark_k]

Originally Posted by mark_k

1. With Null filter, No scaling, the Amiga display is shrunk vertically by 31 or 32 rows. Rows of pixels are missing regularly all the way down the screen. Changing the filter to none, the Workbench is shown 1:1 without missing pixels.

A small update on that issue. I can see the problem running under Wine too, not only in a Windows XP VM.

With the emulated Amiga set to NTSC, ECS Agnus, using a 640x560 PAL overscan Workbench I see the missing rows of pixels.

However, with the same config except the emulated Amiga set to PAL, with the same 640x560 PAL Workbench there are no missing rows.

The attached logs and config file (created running under Wine) probably won't help with figuring out this issue. But they were created by running WinUAE, loading a config file then starting emulation (NTSC Amiga). After workbench loads showing missing rows of pixels, bring up GUI, set Amiga to PAL and reset. Boot to Workbench with no missing lines.

[mark_k]

I've been able to reproduce the missing lines issue in native Windows Vista too.

Attached are config files which should be identical apart from the PAL/NTSC setting. The NTSC config shows missing lines, the other one doesn't. To show the problem: load the NTSC config file. Boot a WB 3.1 floppy. Run the PAL monitor driver from the 3.1 Storage disk, then run screenmode prefs and set Workbench to PAL interlaced. You can use WBPattern prefs to set a checkerboard WB backdrop pattern so the missing lines are easily visible.

There are also missing lines when you set Workbench to PAL non-interlaced, but (at least with a checkerboard WB pattern) they are more visible with an interlaced WB.

Toni: I can send a bootable floppy image which will hopefully allow you to reproduce the problem if that would be easier. You could also use the "jitter test" ADF if you copy the PAL monitor driver to DEVS:Monitors.

Edit: I've attached a WBPattern.prefs file which shows the missing rows more clearly (alternate horizontal lines are white then black in the pattern).

Edit 2: So the issue seems to be this: With an NTSC emulated Amiga showing a PAL display [so ECS Agnus, full ECS, or AGA needed], when using Null filter + No scaling the output image is shrunk in height by 32 pixels.

[mark_k]

Here are another couple of screenshots taken in Windows Vista.

In both cases the emulated Amiga is showing a 640x560 PAL Workbench. The one with missing lines (and shifted-up display position with black space at the bottom) is an NTSC machine, the correct-looking one is a PAL machine.

The same missing lines issue is present with both Direct3D and DirectDraw graphics API modes.

[Toni Wilen]

Originally Posted by mark_k

Edit 2: So the issue seems to be this: With an NTSC emulated Amiga showing a PAL display [so ECS Agnus, full ECS, or AGA needed], when using Null filter + No scaling the output image is shrunk in height by 32 pixels.

This is by design so that PAL/NTSC switch, when (for example) showing early boot menu, appears to work like on real Amigas.

Technically it is correct but as you have noticed, it may not look too good