Analog composite output delay

I need to connect a videoprojector to the ATEM 1.
I'm working in 1080i with HD-SDI cameras, and have 50 ms delai.
Do you have a experience with PGM analog output for videoprojector delai ?
Probleme with lip synch ??
Thanks

If you are going from HD to Sd there is going to be more delay. The best way to eliminate delay is to reduce the number of times that the switcher has to do something to the signal. In your case you are coming into the switcher HD-SDI, assuming that your cameras are not genlocked with the switcher then the farm sync is introducing 1 frame of delay on the inputs. Then you are down converting to SD, that's another frame. Then you are converting from digital to analog, that's another frame. So now you are at a minimum of 3 frames and you haven't even gotten to your projectors yet. If you have anything else in line between the switcher and the projector then you could be introducing more delay. If the projector is having to convert the signal, i.e. you are sending the projector a 720x486 signal that it is projecting at 1024x768, then you are adding more delay.

There are several things you could do:

1. Genlock your signals
2. Digital output to your projectors
3. HD projection
4. Switch your sources to SD
5. Match the resolution of your projectors to your output

To minimize delay in our system we switched our cameras to 720, component out (Only thing our projectors will accept) and set our projectors to 1024x768 for minimal scaling.

Hope this helps.
K