288 pixels horizontal resolution

[ross]

Originally Posted by VladR

I imagine CRT monitors to be finicky about the required frequency, that was quite fun back in the day...

But these days with LCD, this shouldn't be an issue, I reckon ?

CRT technology is not the problem, but the support of those frequencies. Not a problem at all for a good multisync, but a big no-no on any 15Kz TV or monitor.

However it seems to me that you are missing the main problem: if you double the horizontal frequency you also have to double the number of video lines to have the same frequency.
This implies that your resolution will no longer be 160x200 but 160x400.
Of course you can, with the help of the modulo, easily have 160x200 but this does not prevent you from having to give up on half the video bandwidht, used by the DMA channels of the bitplanes (i.e. same as 320x200; yes, no free lunch sorry)..

Originally Posted by rothers

How would sprites behave in such a resolution?

The usual 140ns pixels (on ECS).

[VladR]

Originally Posted by ross

However it seems to me that you are missing the main problem: if you double the horizontal frequency you also have to double the number of video lines to have the same frequency.
This implies that your resolution will no longer be 160x200 but 160x400.
Of course you can, with the help of the modulo, easily have 160x200 but this does not prevent you from having to give up on half the video bandwidht, used by the DMA channels of the bitplanes (i.e. same as 320x200; yes, no free lunch sorry)..

Ouch, that really sucks. The whole point of 160x200 was to have to compute and render 50% of pixels compared to 320x200 and gain additional DMA slots due to less data being transferred.
Oh, well. No free lunch, indeed

[paraj]

Originally Posted by ross

CRT technology is not the problem, but the support of those frequencies. Not a problem at all for a good multisync, but a big no-no on any 15Kz TV or monitor.

However it seems to me that you are missing the main problem: if you double the horizontal frequency you also have to double the number of video lines to have the same frequency.
This implies that your resolution will no longer be 160x200 but 160x400.
Of course you can, with the help of the modulo, easily have 160x200 but this does not prevent you from having to give up on half the video bandwidht, used by the DMA channels of the bitplanes (i.e. same as 320x200; yes, no free lunch sorry)..

Just out of curiosity could you halve vertical resolution? I mean, if you're going to require a good multisync monitor anyway...
For the DMA bandwidth, I guess you could just set BPLCON0=0 every other scanline (like e.g. planet rock lobster in voxel part).
What do the basics of setting up such a mode look like? Just a few key register values would suffice and I'll look up the rest

[ross]

Originally Posted by paraj

Just out of curiosity could you halve vertical resolution? I mean, if you're going to require a good multisync monitor anyway...

Yes, you could; or better, an Amiga ECS+ allows it.
But I have no idea if there are monitors that appreciate ~31KHz horizontal, ~120Hz vertical and 200 visible video lines (~262 raw video lines)

For the DMA bandwidth, I guess you could just set BPLCON0=0 every other scanline (like e.g. planet rock lobster in voxel part).

Yes, this might work.
BUT the brightness of the original image is compromised (you need to increase the brightness a lot to compensate for the alternating black lines); technically you may not even make them completely black..

What do the basics of setting up such a mode look like? Just a few key register values would suffice and I'll look up the rest

Well, primarily HTOTAL and VTOTAL
But obviously the other programmable registers must also be set accordingly (H&V sync, H&V blank registers,...).
In practice you have to know what signals the various video devices expect (for example you could study VESA documents) and 'emulate' them thanks to the Amiga signals (normally based on CCK and (sub)-multiples).

And remember that halving HTOTAL is not enough, because the ENTIRE system of predefined DMA channels continues to function as before.

The discussion at this point would become complex, there are many details to consider, but I advise you to observe what the system monitors drivers do.