Artifacting on the A8...

[Mclaneinc]

Try repeatedly pressing Left Alt+9 or Left Alt+0.

 

As you know, artifact colours are different between different Atari models. Currently it is emulated by having a variable parameter called "burst phase", which can be changed using the above keys. I've actually cheated a little and set the "burst phase" differently for each screenshot.

 

Also, see DOC/USAGE, section "SDL keyboard, joystick and other controllers", for other key combinations.

 

 

Thanks, will read the docs in a min..

 

Just one question, do we know if this burst phase setting actually gives the right colours?

[Mclaneinc]

Another related question, do the gr.15 hacks show the correct colour that the artifacted gr.8 screen did?

[thorfdbg]

Another related question, do the gr.15 hacks show the correct colour that the artifacted gr.8 screen did?

It surely doesn't. The reason is that with artifacting, both the bit patterns

0000011000000

0000110000000

 

appear as a solid white line with some color blurring around it, whereas in Antic E only the latter would be white with no color artifacts, and the former would

be only color without white.

 

So long,

Thomas

[thorfdbg]

Just one question, do we know if this burst phase setting actually gives the right colours?

 

It creates "one correct interpretation" of the signal. In reality, it depends on the TV pretty much, and on the cable in between.

 

So long,

Thomas

[Kr0tki]

Just one question, do we know if this burst phase setting actually gives the right colours?

We'll never know until someone determines the difference between phase of the colorburst signal and phase of the clock that generates pixels in GTIA, in different Atari models. Either by manually measuring them, or by examining the schematics.

 

It creates "one correct interpretation" of the signal. In reality, it depends on the TV pretty much, and on the cable in between.

Are you implying that features of a cable or a TV can influence the colours of artifacts, and at the same time don't influence colours generated traditionally?

 

I would say that colours of artifacts are only dependent on the Atari's motherboard version.

Edited August 26, 2009 by Kr0tki

[SeaGtGruff]

It creates "one correct interpretation" of the signal. In reality, it depends on the TV pretty much, and on the cable in between.

Are you implying that features of a cable or a TV can influence the colours of artifacts, and at the same time don't influence colours generated traditionally?

 

I would say that colours of artifacts are only dependent on the Atari's motherboard version.

I can't answer for him about what he was implying, but I know that all TVs are not the same when it comes to colors-- although there's probably a lot more consistency these days than there used to be in "the old days." And I've heard that the quality of the picture on an Atari 8-bit can be affected by the type of cable (and I suppose how good the cable is). These things would surely affect "colours generated traditionally" as well, but they might not be as "sensitive" to the differences (or rather, the differences might not be quite as readily apparent) as with artifacted colors.

 

Michael

[atariksi]

Colors also seem to be affected by the GTIA chip in the machine. I swapped a GTIA chip from A5200 with one from A800 and colors were way off and I had to adjust the potentiometer in the A5200 to get the colors close to the A800 ones.

[Kr0tki]

These things would surely affect "colours generated traditionally" as well, but they might not be as "sensitive" to the differences (or rather, the differences might not be quite as readily apparent) as with artifacted colors.

But, the TV signal that leaves the composite video port of the Atari, already has the artifacts encoded in the form that is physically indisinguishable from a normal colour signal; the artifacts actually become a normal colour signal. Therefore I don't know how a cable or a TV would recognise the difference.

 

Colors also seem to be affected by the GTIA chip in the machine. I swapped a GTIA chip from A5200 with one from A800 and colors were way off and I had to adjust the potentiometer in the A5200 to get the colors close to the A800 ones.

Are you speaking about the artifacting colours? Also, does the potentiometer affect all colours, or only those not generated by artifacting?

Edited August 27, 2009 by Kr0tki

[Paul Westphal]

My buddy put s-video mod in my 130xe, and it made a huuuge difference.

[Frankie]

Except when you use svideo you lose artifacting.

Edited May 3, 2014 by Frankie

[Bryan]

Yep, artifacting relies on the TV/monitor not being able to cleanly separate color and luminance signals. S-video solves that problem and shows you the checkered/banding luminance patterns being used to trigger the colors.

[576XE]

I remember that KJMann said that his mods kills all artifacting.

[Kjmann]

I remember that KJMann said that his mods kills all artifacting.

 

That's correct. when one of my old video mods are used in S-Video mode, The artifacting is lost.

 

I'm almost done with a new video upgrade that is a board that plugs directly into the GTIA socket. It uses the Fairchild FMS6400 Video Driver IC. if all goes well, it should produce a clean S-Video Signal as well as a Clean Composite Signal and be easy to install.

 

I've found if I use a Resistor and diode to bleed a little bit of the chroma signal into the Luma Signal, using a switch to turn this on and off, I can get the artifacting effect while using S-Video.

 

Hey Flashjazzcat, Are you interested in testing one of these?

Edited May 3, 2014 by Kjmann

[Tempest]

I had that s-video artifacting mod on my 800. It worked pretty well actually. Unfortunately I had to remove it when I did my Incognito upgrade. I should do something like that again.

[flashjazzcat]

Hey Flashjazzcat, Are you interested in testing one of these?

You know it. I was always very impressed by the picture quality from the s-video boards you used to produce, and I still have a couple. I'm interested to see how far quality can be pushed with a Y/C signal.

[576XE]

You never beleive this but I found New CRT Sony PVM 14L2 in ... Lenin's Mausoleum!!!

 

I'm afraid it's some kind of joke...

But i have a link:

http://www.avito.ru/moskva/audio_i_video/videomonitor_sony_pvm-14l2_199868289

 

Next link

Город Москва показать на карте

(under a picture) leads to ... Red Square -> Lenin's Mausoleum!!!

2500 rubs is near 75 bucks

[Kjmann]

You know it. I was always very impressed by the picture quality from the s-video boards you used to produce, and I still have a couple. I'm interested to see how far quality can be pushed with a Y/C signal.

Ok. As soon as i get them all put together, i will send you one.

 

PM me your address to ship it to

 

=)