I don't believe I have that. 

The GPU is asynchonous, and there are a couple of seconds of queued packets going to the GPU. There isn't even a fixed offset between OMXMediaTime (the pts of the current audio/video frame being output) and the host's GetAbsoluteClock (OMXMediaTime can speed up and slow down when timestamps don't fit the media packets).

My belief is the correct behaviour is to query OMXMediaTime, and produce the subtitle that corresponds to that time. If I know there is a one or two frame latency through the rendering system it may make sense to add that to OMXMediaTime, but that is a small effect.

I don't understand how to get an absolute clock without doing the calculations that this pull request is designed to remove.