I want to flip a composite signal...

Why not just reverse the leads to the vertical deflection coil?

You'd have to digitize it a frame at a time, flip it in memory and then send it out to a DAC. It's far from trivial.

Yes, and it's called a mirror.

Is this the solution to reversing camera's.

I am using a cheap security video monitor as a rear view behind a caravan but the picture is reversed. ie LHS is on RHS of screen. If I swap the horizontal deflection leads this should work?

Regards Norm

Unfortunately due to the magic of science, a mirror only swaps left to right, it doesn't swap top to bottom

Regards Norm

Yep it should.

Mike

Yes, that's exactly what you want to do. Swap the vertical and you get upside down, swap the horizontal and you get mirror image. Make sure you don't mix horizontal with vertical.

As others have said, reversing the scan coils is the way it's done. Many commercial surveillance monitors in the CRT days, had separate and reversible plugs for the field and line deflection coils, just so that you could mount a camera either on a top mount or a hanging mount. I've also seen the ability to reverse the scan in the camera itself. Been a while since I've been involved, so I don't know what the situation is now with LCD monitors. I guess that a camera with the ability to reverse its output is still ok, and also, the last controllers that I worked with were full of fancy features, and actually had the frame stores that James was talking about, but I can't recall now whether reversing the picture was one such feature.

Arfa

He probably wants to view in a mirror.

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If it is a CRT monitor, yes that will work.

You can also put a mirror in front of the camera, for either horizontal or vertical inversion.

Well here's an interesting question.. What happens if you switch the verticle and the horizontal. Will it change your picture orientation or will it fail to start up. Just curious about ways to change the orientation for old Arcade games that had the monitors mounted vertically. Just curious if I could flip the entire picture vertically so that I can use a PC in my arcade cabinet. i.e. Turn your computer monitor on its side and have the picture correct.

Mike

It will blow out the horizontal output transistor, and probably fry the vertical output as well. The two coils have dramatically different impedance since the horizontal scan coil is part of a resonant circuit also used to generate the high voltage and other voltages used in the monitor..

Vertical monitor games were coded to display right with the monitor on it's side. The scan still sweeps across the long dimension of the tube. MAME has a setting to rotate the picture so you can use a standard PC monitor on its side, or you can display the game on a horizontal monitor with black bars on either side of the vertical picture. Google MAME cabinets, hundreds of people have built these already.

He finally said it's for a vehicle. He should just buy a system made for the purpose.

for example.

B&W or color CRT monitor? It will work with B&W, but will need more work to modify a color CRT monitor. LCD will need to be digitized and mirrored in software, in real time.

Then you need two mirrors, or turn the monitor upside down. ;-)

It makes no difference whether it's B&W or color. I've done a lot of service work on arcade game monitors, and it's common to have to flip yoke plugs. Some games mount vertical monitors on one side, some on the other side, some horizontal monitors are mounted upside down, there's really no standard. Flip the wires and the picture flips, that's all there is to it. One place I worked I used to swap the yoke wires in people's tvs as a prank.

Many small LCD monitors have a switch to toggle mirroring.

Thanks for the pointer on MAME. I'm allready using it that way, but it would be nice to be able to do everything without having to look at it sideways.. I can already play games oriented properly, but using dos is a bit of a challenge at times. I kind of guessed that it wouldn't work because of the scan rate differences between the two, horizontal being in the kilohertz range and vertical just being around 60 hertz or so.

Thanks Mike

Just get a flippable monitor. There were a few CRTs like that, and many LCDs are available which simply swivel 90 degrees. I haven't used the DOS version of MAME in over a decade, the Windows version has the same functionality.