GBS Control / GBS-C video modes

[Asmodean]

I bought a GBS-C from China a couple of months ago to use with my A1200. It works great with the regular PAL resolutions in 15khz. However, I have not managed to get it working with any of the DblPAL or Productivity modes.

Anyone had any luck in using these other modes?

[LordCrass]

It's designed to deal with 15kHz inputs only.

[pandy71]

Originally Posted by LordCrass

It's designed to deal with 15kHz inputs only.

This is software limitation not HW limitations.

[giantclam]

I think gbs-control syncs to 25kHz.... https://github.com/ramapcsx2/gbs-control

[Jope]

I'm sure it will go higher than that via the VGA connector, if it claims to support up to 1600x1200.. That requires around 75kHz.

[derSammler]

I'm sure it will go higher than that via the VGA connector

All inputs are the same, they are all wired to the same traces.

As pandy71 noted, that is a software issue.

[jbilander]

Originally Posted by Asmodean

Anyone had any luck in using these other modes?

A long time since I last fiddled with GBS-Control but I seem to remember there was a pass-through mode that you could activate by clicking a button in the web config.

[LordCrass]

What would be the purpose of using these modes? The whole point of them was to work with 31kHz monitors and no flicker. You already get both of those benefits with the GBS-C as long as you are using the motion adaptive deinterlacer.

[pandy71]

Originally Posted by LordCrass

What would be the purpose of using these modes? The whole point of them was to work with 31kHz monitors and no flicker. You already get both of those benefits with the GBS-C as long as you are using the motion adaptive deinterlacer.

Problem is that most of Amiga video is not truly interlaced but PsF https://en.wikipedia.org/wiki/Progre...useskin=vector so progressive video sent over interlaced sequence - deinterlacing even adaptive will impair video quality.
There are some exceptions (such as ClariSSA) where interlace was used intentionally to improve temporal resolution and deliver smooth motion.

[Asmodean]

Originally Posted by pandy71

Problem is that most of Amiga video is not truly interlaced but PsF https://en.wikipedia.org/wiki/Progre...useskin=vector so progressive video sent over interlaced sequence - deinterlacing even adaptive will impair video quality.
There are some exceptions (such as ClariSSA) where interlace was used intentionally to improve temporal resolution and deliver smooth motion.

Ideally it would be nice to run Workbench in 640x512 resolution non-interlaced in 31khz resolution without the degraded artefacts introduced by interlacing and then be able to run all low-res content like games/demos. I take it that the GBS-C does not allow for this yet then

[pandy71]

Originally Posted by Asmodean

Ideally it would be nice to run Workbench in 640x512 resolution non-interlaced in 31khz resolution without the degraded artefacts introduced by interlacing and then be able to run all low-res content like games/demos. I take it that the GBS-C does not allow for this yet then

So you don't need deinterlacing as deinterlacing convert field to frame and missing lines need to be interpolated - there are various flavors of interpolations or even trained guess (i.e. AI) but in most Amiga cases you have simply progressive screen transferred in two phases so all you need to do it Amber approach - store field, store line, output field interleaved with new filed twice faster.