PS: Here are two scripts to calculate QuickTime time → SMTPE and vice versa
QuickTime time → SMTPE:
property TimeOffset : 10
tell application "QuickTime Player"
tell document 1 to set {currentTime, timeScale, theDuration, FrameCount} to {current time, time scale, duration, count (frames of track "Video track")}
end tell
set FrameRate to (FrameCount * timeScale) / theDuration div 1
tell (currentTime / timeScale) to set {hr, mn, sc} to {it div 3600, it mod 3600 div 60, it mod 3600 mod 60 div 1}
set fr to (currentTime mod timeScale div (timeScale / FrameRate))
set SMPTE to addZero(TimeOffset + hr) & ":" & addZero(mn) & ":" & addZero(sc) & ":" & addZero(fr)
display dialog "TCR " & SMPTE
on addZero(v)
return text -2 thru -1 of ("0" & v)
end addZero
SMTPE → QuickTime time:
property TimeOffset : 10
set SMTPE to "10:20:24:20"
set {hr, mn, sc, fr} to words of SMTPE
tell application "QuickTime Player"
tell document 1 to set {timeScale, theDuration, FrameCount} to {time scale, duration, count (frames of track "Video track")}
end tell
set FrameRate to (FrameCount * timeScale) / theDuration div 1
set QT_time to ((((hr as integer) - TimeOffset) * 3600 + mn * 60 + sc) * FrameRate + fr) * (timeScale / FrameRate)