> So I really think we can utterly disregard render stage for lateness detection.

hw decoders like vdpau and vaapi are asynchronous. A call to decode may return instantly or may block due to state of the render pipeline. This makes lateness detection at decoder extremely inaccurate. 

> Imho clock object should not care about lateness. It should just be a sync time.

Does not need to be the clock object. I think if we had a central place where we collect data from audio and video, we would do easier in sync those two.

> we can switch, but it must be done by passing the clock down from player in the configure call

if you are not opposed to this, I will look into audio. I need to touch the interface anyway for handling planar formats.