Aside from the convenience of having one monitor that can switch between RGBI and Composite is there any downside in using a composite of a TV instead of a monitor? I can't imagine there would be an difference in image quality since composite graphics were notoriously blurry anyway?
It depends on the monitor/TV set, I believe. In essence, they work the same internally.
Back in time, our TV sets had no composite (CVBS) inputs, just an RF input.
That was an integrated composite monitor+VHF tuner combo, so to say.
In contrast to TV sets, pure composite or monochrome monitors were sometimes called "video monitors".
Quality monitors also had comb filters, which did set them apart from cheap 90s era TV sets with those red, black, yellow jacks.
RGB/SCART is a special case, perhaps, not sure.
Ediit: Video monitors also had knobs for v-hold,h-hold, v-size, h-size, 50Ohms/75Ohms inputs, etc.
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
//My video channel//
For me, the only MAJOR downside of using a TV is that the picture isn't properly centered. This is a result of how the BIOS initializes video modes, specifically the values for the HSync Position CRTC register. On my CRT TV everything is shifted too far to the left, so that the edge of the active area is actually hidden under the TV's bezel. There's no H-Position control on the TV either (most composite monitors should have one).
This problem is why many CGA-era games had specific controls to shift the screen left/right, but many more don't let you do that. The MODE command in DOS can help, but it's buggy... and even if it wasn't, it can't work with booters (naturally). So I've been working on a couple of small utilities to fix this (if anyone else needs them, I could post them when they're done).
Looking forward to seeing these utilities -- I already have too many CRT monitors and would prefer to avoid getting another for composite.
Sure, might take a while due to other commitments but I'll share the results. BTW, I should mention that the above problem only applies to the CRT TV I'm using - I do believe that most new-ish flat panel TVs are more forgiving, as long as they have composite inputs of course. My rather crappy AKAI HDTV always shows the full overscan, has position and aspect ratio controls, and handles any oddity that the CGA throws at it, ironically much better than the CRT does. It also employs a comb filter which reduces that NTSC color bleed on sharp transitions. So if you don't mind the "less authentic" scenario of using a flat panel TV, that's probably the way to go.
Isn't the NTSC color bleed essential for proper 16 color CGA composite?
Not exactly, it's more of a side effect. In another thread I took a couple of photos to show the difference between the CRT and the HDTV, so you can see what I'm talking about: Re: Video card on Compaq Portable 286?
More info about comb filters and how they work: http://www.cockam.com/vidcomb.htm
^Cool, thank you very much! This was very informative - I bookmarket the links. 😎
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
//My video channel//
