Pedanticism aside lexor (we have other lives too, we're not on here 24/7, so quit bugging when we ask something a bit "late"
), those are quite conservative settings. 2 Refs and 2 B-frames for 4 Mbits? If it's very fast motion, 4 Mbits won't be enough, so either increase the bitrate, or increase the Refs and B-frames. 8 for each would be a could number.