public void UpdateCurrentClipFrameAbsPos(VidkaProj proj)
{
CurrentClipFrameAbsPos = null;
if (CurrentVideoClip != null && proj != null)
CurrentClipFrameAbsPos = (long?)proj.GetVideoClipAbsFramePositionLeft(CurrentVideoClip);
else if (CurrentAudioClip != null)
CurrentClipFrameAbsPos = (long?)CurrentAudioClip.FrameOffset;
}