[Soli]

In theory it is 1/fps. That means 20 ms for 50, 16 for 60 and >40 for 24p.

Now consider a TV doing post processing, e.g. color enhancement or 100hz calc bs which needs 3 frames queued ...

I suggest: measure your personal value once and for all and put it per refreshrate into advancedsettings and be happy.

Edit: concerning the question, yes we add our introduced delay and tell dvdplayer to keep that value in mind before resyncing, which would happen when 200 ms off.

IMO it's flat out wrong wrong to set a delay of 23-24fps vsync to 175ms as default in OE.
The TV might do 200 frames of post processing and it wouldn't matter. The sound output from the TV will be delayed exactly the same. I have yet to experience a TV that didn't do this properly. Yes a lot of TVs do all sorts of crappy things, but audio delay? Never a problem whatsoever.

This is only an issue when you run the signal into an AV receiver and HDMI from receiver to TV.
Then you would need to do one of 2 things:
1. Nothing, as the TV will report it's delay through HDMI's 1.3b lip sync feature and they will automatically sort out the delay.
2. You adjust the lipsync/delay in the receiver.

You do not ever mess with the delay from source, unless you're running sound directly (i.e analog audio output) to an amplifier and use HDMI only for picture. Even then the delay would be global.

There's no reason to set a delay specifically for 23-24hz, unless there is a bug in the software itself at these rates. (That's not meant to be passive aggressive rhetorical, 23-24hz works as intended @ my home' without needing to set a special delay for 23-24hz)