Image differences? DB23->VGA vs Composite

[pedrorq]

I've tried connecting my Amiga 1200 to my Dell 2001fp (that supports 15KHz) by both DB23->VGA (using an adapter) and by composite, and I'm a bit baffled at the results.

(Please bear in mind that note the images are scaled to 1600x1200, the Dell's native resolution. Also, it's not very easy to capture the details by photographing a monitor... )


On DB23-VGA, the image is clear, with a few vertical stripes:

http://i.imgur.com/PCO2p1t.jpg

On composite, the image is grainy/blurry

http://i.imgur.com/Kt3w4fh.jpg


Are these expected results? I was expecting better from the composite. Could it be the cable?
Are those vertical stripes on the DB23 output normal?

TIA!

[robinsonb5]

Originally Posted by pedrorq

Are these expected results? I was expecting better from the composite. Could it be the cable?

Are those vertical stripes on the DB23 output normal?

Both results are pretty much normal.

Time dulls the memory of how rubbish composite video actually is!

The vertical stripes are an interference pattern between the monitor's pixel sampling clock and the Amiga's pixel clock, which isn't what the monitor expects. You may be able to reduce them by bringing up the monitor's OSD and fiddling with the clock control.

[demolition]

In the menus on my Dell monitor you can disable any scaling, so you should try that. The picture will be small, but it will reveal whether the artifacts come from scaling or not. Also while in WB, try to use the auto calibration on the monitor. It doesn't work when the picture is black so it is often a good idea to start it manually once the picture is on and stable. If these two does not reveal anything, start fiddling with the phase like #2 writes.

I agree with #2 as for the composite. It looks like it usually does and composite was never good. A good RF connection is about equal in quality to composite.

[Amiga1992]

Composite is shit. Of course this is normal.
Stick to RGB.

[demolition]

To find the optimal settings, I usually make a small 2x2 bitmap containing black and white pixels which will show any interference patterns very clearly.

Make a 2x2 bitmap like this:
w b
b w
w=white, b=black
Set it as background image with tile on.
Now watch the horrible flicker and lines.

[fryguy]

Yep Composite is crap, if your monitor doesn't have a Scart connector, you can use S-Video
(i think someone on amibay sells such adapters)

[pedrorq]

The DB23-VGA adapter works beautifully - I can live with the vertical lines (can't find any clock configuration on the OSD as #2 suggested).

I wanted to try the composite so I could use PIP. It's OK for that as you can't really see the granularity on the small PIP window, but more than that (full screen) it's really not that nice.

Thank you all!

[Amiga1992]

I have to say that you get a pretty decent composite signal anyway, probably your monitor is cool

[robinsonb5]

Originally Posted by pedrorq

(can't find any clock configuration on the OSD as #2 suggested).

Should be under Main Menu -> Image Settings -> Pixel Clock, according to this guide:
http://stuartconnections.com/product...n/controls.htm

[pedrorq]

Originally Posted by Akira

I have to say that you get a pretty decent composite signal anyway, probably your monitor is cool

Thanks! Except for the glitch of the image de-centering every time the Amiga reboots/starts, it is very nice and, I believe, a recommended one to use with the Amiga.

Originally Posted by robinsonb5

Should be under Main Menu -> Image Settings -> Pixel Clock, according to this guide:
http://stuartconnections.com/product...n/controls.htm

Unfortunately the Image Settings menu is not available (greyed out) when connected through VGA