<blockquote=”Michael”>There is a function pointer called vbi_hook that runs every time a frame ends (in the vertical blanking interval). You can define a function for the vbi_hook and increment a counter in it. If you want to access the counter value from outside an interrupt service routine (e.g. to display it), make sure you declare your counter variable as volatile.
Or you can increment your counter in the ISR that runs every time a new frame starts: [tt:3j0g3aqq]ISR(TIMER1_OVF_vect)[/tt:3j0g3aqq]
All this code is in [tt:3j0g3aqq]video_gen.cpp[/tt:3j0g3aqq]