Interlaced CDTV Demo Issue

[Amimal]

Hello Toni. I'm having trouble getting "Commodore Amiga CDTV, Amiga 600, Amiga 600HD Demo Disc 2 (1992)(Commodore).iso" to display correctly when using "Double, fields+" as interlaced line mode. Whenever the demo switches to an interlaced screen, the image appears to randomly "jump", which thing won't happen with other interlaced line modes. It could be that it's displaying a frame twice or something like that, but I have not recorded a video and gone frame by frame to tell for sure. Howbeit, if that will at all help, let me know I'll get around it. This happens with both the official standard release as well as with the latest beta. Both with and without cycle exact on. My personal config (not the one attached, which's essentially a "defaults" settings run save for the cycle exact being on and the interlaced line mode change) doesn't help either, only it makes the jumping more noticeable because it goes fullscreen+50hz+vsync. I've also tried different bootroms, but they don't seem to make a difference. I couldn't get the savestate to trigger the jumping, though I still get it every time I run the demo the conventional way.

No problems so far with other interlaced software. be it under CDTV or A500 profiles.

Thanks for your time and for this most amazing emulator

[Toni Wilen]

I think it is normal and side-effect how lace<>nonlace switching works in emulation (it waits a bit before deciding what to do)

This demo disc is not good test case for improving it. (Too slow, CDTV only etc..)

[Amimal]

Thank you Toni for looking into it. But just to get a better picture here; if the original demo CD, pristine and unscratched, were to be played from a properly functioning CDTV unit, would this still happen?

[Toni Wilen]

Originally Posted by Amimal

Thank you Toni for looking into it. But just to get a better picture here; if the original demo CD, pristine and unscratched, were to be played from a properly functioning CDTV unit, would this still happen?

No, it looked fine. (I actually tested it yesterday. Real hardware test is always the most important part! CDTV + 1084 display) But there may be chance that it still happens if switching happens exactly when display decides field mode (odd or even).

Hmm.. I guess switching delay can be reduced/removed in "fields" interlace mode (delay does make sense in "frames" mode because it needs both fields before it can show anything). I'll test..