Is ENTER_FRAME dispatched at the end of vertical blanking signal or at the start of window?

Question

Is ENTER_FRAME dispatched at the end of vertical blanking signal (vblank or vsync) -the actual beginning of the frame on the screen, OR at the beginning of the flash window (if the stage3D app is in window mode), OR in an imprecise timing (depending on the ...internal mood of Flash)?

(I'm using pure AS3 and Stage3D with 3D GPU rendering -no 2D display objects, Flash timeline, movieclips etc).

EDIT: See relative question: Can the ENTER_FRAME be missed or received delayed by the listener?

Answer 1

A bit old but still mostly true: http://www.craftymind.com/2008/04/18/updated-elastic-racetrack-for-flash-9-and-avm2/

So shortly said - ENTER_FRAME is dispatched at the beginning of the frame, then code is executed, and after all that, the render begins (I don't know what you exactly mean by vblank, vsync or 'beginning of the frame on the screen')..