I made a small movie that has 24 frames of black and then one frame of white. On every white frame there is a pop around 500 hz.
I play the movie on Nuendo and video it from the screen and record it with onboard mic with handycam or similar. Then I import the new handycammed video to nuendo and check from the timeline how much white frame and pop are drifted. Then fix it in Nuendo and handycam the original video once more.
Then import new handycammed video to nuendo and check if aligned properly. If not, another fix and then another round again.
Takes time but works. Have checked 2 systems like this. And verified first with syncheck to see if this works. It works.
Bye / Tumppi