Good question. And perhaps I should have mentioned one more thing in the tutorial which is this: All of our rhythm parts (like arp piano or drum beats etc.) are 120bpm. When all video scenes are multiple of full seconds in lengths they will fall in to beats, so when we drop tonal sound signatures from "Evince" on the begining of those scenes they will fall on first, sceond, third or fourth beat of the musical bar and it will sound nicely and rhytmical. Here is another tutorial about this technique: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-YfAFurGFQhE.html Hope this helps. Please let me know if you have any more questions.