Atari and modern displays

[morelenmir]

There are many threads which discuss the various ways to get a signal from the slightly bespoke Atari 800 XL 'video' DIN socket in a format compatible with a modern television's SVIDEO input. There are also a few mods - always requiring new add-in boards - to get a VGA signal for a CRT monitor. So far however I have not found an all-in-one mod to output a signal compatible with HDMI. For quite a while I mistakenly believed the VBXE board would do it, but on further research this seems to not be the case. I believe an additional standalone upscaler device is needed to sit between the 800xl and the monitor?

 

Like everyone else cost is the greatest factor in all my Atari nostalgia. However desk space is for me just as limiting. Simply put, I have absolutely nowhere to place either an old CRT monitor or worse yet 80's-era television. If I cannot sit my old XL on the desk top and plug it in to my existing LCD display - through whatever technological jiggery-pokery - I cannot run it. Therefore I wonder if anyone can suggest a way to accomplish this, specifically atari out and HDMI in?

[Rybags]

HDMI is a glorified network cable in certain ways - the video is digital.

 

For now, generic blackbox adaptor devices are about the best option. Take the best available video source from Atari which is S-Video in essence (seperate chroma/luma).

 

Some day somebody might develop something that lets us have HDMI and/or Component out directly. We have an advantageous starting point in that:

 

- Colour and luma information are output seperately at chip level.

- Luma output is digital at the source.

- Colour from the source is a waveform that has a phase delay in relation to the input clock source. This relationship could be used to work out which colour is in effect.

 

A custom device for Atari in my mind would allow different palette variations, e.g. one weakness of the Atari video is that the saturation is way too much on dark shades and way too weak on brighter ones. A device that changes the video output medium could provide it's own interpretation for every single colour.

[BillC]

There are many threads which discuss the various ways to get a signal from the slightly bespoke Atari 800 XL 'video' DIN socket in a format compatible with a modern television's SVIDEO input. There are also a few mods - always requiring new add-in boards - to get a VGA signal for a CRT monitor. So far however I have not found an all-in-one mod to output a signal compatible with HDMI. For quite a while I mistakenly believed the VBXE board would do it, but on further research this seems to not be the case. I believe an additional standalone upscaler device is needed to sit between the 800xl and the monitor?

 

Like everyone else cost is the greatest factor in all my Atari nostalgia. However desk space is for me just as limiting. Simply put, I have absolutely nowhere to place either an old CRT monitor or worse yet 80's-era television. If I cannot sit my old XL on the desk top and plug it in to my existing LCD display - through whatever technological jiggery-pokery - I cannot run it. Therefore I wonder if anyone can suggest a way to accomplish this, specifically atari out and HDMI in?

The DVDO iScan products have been mentioned, the lower end ones have VGA out while some of the higher end models have HDMI or DVI out. They can be expensive but you can sometimes find them used for a reasonable price.

 

It has been mentioned here that the iScan Ultra won't work with the Atari 8-bit video signal. I know the iScan + does, there are posts about others that do work.

[morelenmir]

That is fascinating rybags - just yesterday I read something about "Ethernet over HDMI", which your network cable analogy explains nicely!

 

In the old days all video cards outputted through those - inaccurately labelled no doubt - 'vga' sockets to the monitor. Were they actually called something like 'DSUB'? Anyway. In the early 2000s it looked liked they were going to be replaced permanently by DVI sockets and cables before everything finally moved to HDMI. However, during the interregnum when all three were available in the wild you often got a handful of different adaptors when you bought a new video board. Would it be possible to use one of those VGA-HDMI adaptors to take the output from VBXE and put it out over an HDMI cable? Obviously you would get no upscaling and as you mention no chance of palette manipulation. However, my monitor does a pretty good job of upscaling its input natively anyway. I wonder if that would be a reasonable interim measure before shelling out on the 'blackbox' dedicated upscaler?

[Faicuai]

(...) However, my monitor does a pretty good job of upscaling its input natively anyway. I wonder if that would be a reasonable interim measure before shelling out on the 'blackbox' dedicated upscaler? (...)

 

Well, this (and other aspects) can be easily tested.

 

Take this little Basic program (for instance), which uses a "high-resolution" pixel-pitch pattern to verify the quality of your scaling with respect to the original 320x192 display. Many factors like over-scanning, aspect-ratio processing, H&V zooming, etc., will invarible affect this test. Overall, You should not see "beat" patterns of any kind (from a short-mid distance), and every single's pixel geometry and sharpness should be identical to any other adjacent next to it:

 

200 GRAPHICS 8+16: COLOR 1

210 POKE 710,1: POKE 712,4

220 X0=0: X1=319: XSTEP=2: XOFFS=0

230 Y0=0: Y1=191: YSTEP=1

240 FOR Y=Y0 TO Y1 STEP YSTEP

250 FOR X=(X0+XOFFS) TO (X1-XOFFS) STEP XSTEP

260 PLOT X,Y

270 NEXT X

280 XOFFS=XOFFS+1

290 IF XOFFS>1 THEN XOFFS=0

300 NEXT Y

999 GOTO 999

 

You could also use it to test proper up-scaling on ANY digital platform you may use, including ALTIRRA itself (whether you are or not in full-screen mode).

 

This is a key component / step for extracting reasonable sharpness and correct representation of detail out of your 8-bitter. Then comes chroma-detail (and noise), and then motion-adaptive de-interlacing (or, in this case, 240p-to-480p re-processing), which is definitely a bit more complex to test, especially with Atari's "all-same-half-fields" progressive analog signal.

[+Stephen]

Another good test is trying FlickerTerm. When it displays properly, a line of underscores will look like _____________. Most, do this instead _-_-_-_-_-_-_-

[+orpheuswaking]

you and your damn Flickerterm

[morelenmir]

I'll give that routine a shot! Many thanks Faicuai!

[Faicuai]

Another good test is trying FlickerTerm. When it displays properly, a line of underscores will look like _____________. Most, do this instead _-_-_-_-_-_-_-

 

Absolutely. I really like this Terminal emulator, overall (such an GREAT 80-cols. emulation).

 

This is both a 240p-processing AND overall SPEED test for your video processor (whether embedded on your display or external).

 

Easiest way to check this is to CTRL+SHIFT+E simultaneously, and enter in "Chat Line". Once there, type the underscore character multiple times. Even more, simply hit START+F simultaneously, and then press "1" to show a directory of the drive... if the screen feels like "tearing" while directory shows up, you have a bad sign of insufficient or improper 240-p processing.

 

A very similar test can be seen in STEALTH: once booted, and let run in "demo" mode, the back of the ship (as it waves through the scenario) shows a couple of exhaust ports which SHOULD flicker and display a pattern clearly different than the rest of the detail of in the screen (simulating exhaust heat/activity). If this does not show, or appears blurred, you have bad 240-p processing (or insufficient horse-power, simply put). This effect is even hard to see on ACTUAL CRT displays where individual scan-lines can be distinguised (it will look better CRT's with LOWER vertical resolutions, ironically).

 

Enjoy!

[+Stephen]

you and your damn Flickerterm

I don't like the program, but it is the definitive test of a scan doubler and whether or not it will properly handle the Atari's signal