Aspect Ratio

[ajordison]

Apologies if this has already been asked (probably by me!) or if this is the wrong forum but what is the aspect ratio of the VIC characters? Are they different for PAL/NTSC machines? I couldn't get a definitive answer from the net, though I didn't look very hard...

Thanks.

[Mike]

what is the aspect ratio of the VIC characters?

I once measured that value with my PAL VIC-20 connected over the RF modulator to a TV set. The TV set was confirmed beforehand to show perfect round circles in the standard test images of the broadcast stations.

The pixel aspect value (identical to the character aspect ratio) I came up with was 1.67:1.00, or 5:3 in small integers.

Most monitors allow you to change screen width and/or height, so unless they have been calibrated with such a test image, measurements of the aspect ratio are unreliable.

Are they different for PAL/NTSC machines?

Yes, they are different. The pixels are slightly less wide, around 1.33:1.00 to 1.50:1.00. Sadly I do not know more accurate numbers, where an NTSC user had confirmed them to be measured on a calibrated TV set or monitor.

BTW, the standard value in VICE, 2:1, is totally off.

[ajordison]

Thanks for that. I thought about getting the values from VICE but then someone else said they were wrong.

[Mike]

That one could quite as well have been me. Just found that thread again.

Unless I'm in a hurry, I also use the 5:3 value to prepare (computed/emulated) screenshots in IrfanView before posting them here. Otherwise these images might look unnaturally squashed.