Scandoubler Needed?

[ErinW]

Hi,

I've been using my A500 (ESC) with an OSSC & BenQ BL702A monitor for a while now. The OSSC does a great job with NTSC Hi-Res Mode but on this monitor at least, it doesn't handle the interlaced modes well, and the PAL modes are unusable - the monitor doesn't support these modes. I've tried various settings on the OSSC and 1x through 5x, but I'm stuck with NTSC Hi-Res on this monitor.

I've tried other LCD monitors (those that don't support 15 Khz like the BenQ), including an old NEC 1970NX Multisync but I haven't been able to get any further.

My OSSC does sometimes have difficulty syncing the signal with the BenQ BL702A and I wonder if it's because the output from the OSSC isn't a 'perfect' 60hz? Would adding a scandoubler and feeding it to the OSSC help? Ideally, I would like to use the "Productivity Mode" too, but one step at a time...

Any ideas?

[stephen_usher]

Monitors aren’t very good for this sort of thing. They only support a very small sub-set of HDMI resolutions.

Remember that the OSSC can’t really change the timings as it’s not storing the frame and re-rendering it, to increase the horizontal resolution it merely over samples and transmits at the higher resolution, adding front and back porch. Similarly it merely repeats scan lines.

For all (non-VGA) retro platforms a TV is by far a superior display device.

[Cosmic Puppet]

I got the OSSC hoping to further improve picture quality. However, I've ended up using it just for playing games and demos on my ASUS computer monitor. Low resolution colour is especially good. My issues are down to my Atari revisions RGB.

Both high and low resolutions work well on my NEC Multisync EA193Mi Monitor. Medium mode is atrocious as it was on my benq 702 (The NEC is better in my opinion.) The low resolution looks blurry compared with the OSSC into the ASUS which is crisp when using the quintuple mode.

[Steve]

Hi @ErinW

I actually went quite in-depth with the OSSC and my Amiga 1200, the following post is the gold you need:
https://videogameperfection.com/forums/ ... for-amiga/

Now besides these OSSC timing profiles the Amiga has lots of internal settings and monitor drivers that make a difference. ie; you can boot your Amiga in NTSC or PAL mode, I think correct me if I'm wrong, by holding both mouse buttons down when turning the machine on.

Also on Aminet you will find a section full of monitor drivers:
https://aminet.net/driver/moni

These change what your Amiga outputs and are selectable under your normal monitor preferences. Some over-write existing profiles and are created for more VGA tolerant timings... You can spend many hours and days playing with these, I know *I did*. Warning: it is easy to forget what you've changed and can easily get frustrating.

But in the end, I just got really annoyed with it. Was really hard to find settings that were suitable for my desktop and games etc. So I bought an Indivision aga upscaler,there is an ECS/OSC version available too.

I hope this info helps!

Edit: Lezreds post reminded me I was originally using SCART and it was terrible. After buying a VGA adaptor everything was much better. Also you can experiment with the VGAOnly driver on your workbench floppy by dragging it into the monitor drivers folder.

[LezRed]

My PAL A500+ and my PAL Atari STE work fine with both my 702A screens. No scandoublers, just a cheap 15 pin VGA adapators http://amigakit.amiga.store/product_inf ... cts_id=183. All interlace screen modes still flicker, but I just use a 4 colour DBLNTSC screen mode on the Amiga to avoid that in Workbench 3.1.

If you want to use interlace modes to have a higher resolution with more than four colours without the interlace flicker then you need a flicker-fixer rather than just a scan doubler. The Indivision ECS v2 from icomp https://icomp.de/shop-icomp/en/shop/pro ... ubler.html is something I have considered buying but I'm not sure I'd get proper value for money as PAL modes used by games work fine and as said I'm happy with DBLNTSC for workbench.

Amiga & STE.png (1.17 MiB) Viewed 4465 times

[ErinW]

Thank you all for your great suggestions!

I have a 25pin -> VGA cable that works with my 702A much like what @LezRed describes, and while it works well enough, I do miss the 4x scaling of the OSSC when using it with games. There's always a trade-off it seems.

I may try an Indivision upscaler/flickerfixer, but I do like solutions that don't involve having to route cables out of the expansion bay.

I may try other monitor profiles too, though I've not had much luck with the DBLNTSC or Productivity mode ones so far, at least not on my 702A.

I'm not sure which route to take, though it's nice that there still more options to explore!

[Steve]

@ErinW you can put that VGA into the OSSC and still get your 4x!

[LezRed]

I may try an Indivision upscaler/flickerfixer, but I do like solutions that don't involve having to route cables out of the expansion bay.

I was thinking it would be possible to mod the case to avoid that if I were to get one, although I do have an ACA500 case that has a VGA connector sized hole in it if it went into that Amiga.

Here's a picture of a RetroHax SVHS/colour composite mod. A VGA connector would be able to fit I think, assuming one is happy to cut holes in an old case

Amiga500 CaseMod.png (323.3 KiB) Viewed 4398 times

I'm now even more curious how games would look via an indivision or OSSC vs. directly to the 702A, I guess the difference is in the scaler?

[ErinW]

@ErinW you can put that VGA into the OSSC and still get your 4x!

I'm not sure why, but I completely forgot the OSSC has a VGA input!? Of course, now that I'm reminded of it, I can't possibly find the right cable!

[ErinW]

I like mods that are completely reversible, so I prefer not to start creating holes in my A500's case.

The scaler really does make a dramatic difference. I recall the image on the 702A looking quite soft when connected directly. The soft picture is what convinced me to buy the OSSC in the first place.

I may try an Indivision upscaler/flickerfixer, but I do like solutions that don't involve having to route cables out of the expansion bay.

I was thinking it would be possible to mod the case to avoid that if I were to get one, although I do have an ACA500 case that has a VGA connector sized hole in it if it went into that Amiga.

Here's a picture of a RetroHax SVHS/colour composite mod. A VGA connector would be able to fit I think, assuming one is happy to cut holes in an old case

Amiga500 CaseMod.png

I'm now even more curious how games would look via an indivision or OSSC vs. directly to the 702A, I guess the difference is in the scaler?