DVI Modification of Neo Geo AES?

[Krobar]

After reading the second NeoRGB article (http://nfg.2y.net/games/neorgb2/) I wondered if this is possible or more importantly viable?

It seems the Neogeos output 7 digital bits representing colour intensity (Giving 49ish intensites) for each colour, anyone have any ideas on how this could be converted to DVI or SDI?

[NFG]

Actually, 7 bits = 128 levels of colour.  Consider:
2 4 8 16 32 64 128

In order to convert this you'd have to use a microcontroller of some sort to read the Neo's digital output and spit out the equivalent in DVI-compatible signals.  

[Krobar]

Thanks for the quick reply, my brain obiously wasnt working to well when I had a think about this one. In theory it doesnt seem like it would be that difficult, you would need some sort of microchip to feed a DVI transmitter with what it needs, I wonder if something half off the shelf could do this?. I suspect it would give a better display than any RGB output if done properly.

I suppose DVI running in RGB 4:4:4 would be a closer match than SDI in Compoonent 4:2:2 and both are less effort than HDMI. How about a digital sound output too for an all digital Neo?

[Aidan]

Forget the microcontroller - it's simply not going to be fast enough to do all the tasks that are necessary.

From memory, the NeoGeo uses a resolution of 320x224, which is below that which DVI supports. I believe the lowest DVI resolution is somewhere around 640x350, but it depends on the DVI device that's doing the display - some won't handle anything below 640x480.  That means you need to scale the video before encoding it for DVI.

I also suspect that the video would be scaled twice. Once in the NeoGeo to bring it up to something that can be transmitted across DVI, and then once again in the display device to bring it up to the device's native resolution.

Sounds like a lot of work for fairly minimal benefits.

[Guest]

Is pixel doubling difficult? (To 640*448). Thirty or so Dead lines wouldn't matter, they could be dealt with by most displays. Alternatively quite a

As for the benefit I dont have much idea, I assume the Sony video driver is some way from perfect (Especially by modern standards). I run a digital display so avoiding a DAC and ADC conversion is prefferable.  

[Aidan]

You'd have to throw the dead lines in there, otherwise the display may decide that it's not a valid DVI signal - that's display dependant rather than anything else though.

The pixel/line doubling shouldn't be that hard if the output from the NeoGeo is 60Hz. You could probably do it on the fly, but I suspect it would be outside the ability for most microcontrollers, as the resulting data stream is going be around 15Mbit/sec if my calcuations are vaguely accurate. You could do it in a FPGA though.

[Krobar]

If you mean is ther any trouble with 480I through DVI well I know my display can do it, SDI is also an option although in this case Im thiking it might be more difficult.