Add FFmpeg binaries

ffmpeg/presets/libvpx-1080p50_60.ffpreset

@@ -0,0 +1,19 @@
+vcodec=libvpx
+
+g=120
+lag-in-frames=25
+deadline=good
+cpu-used=0
+vprofile=1
+qmax=51
+qmin=11
+slices=4
+b=2M
+
+#ignored unless using -pass 2
+maxrate=24M
+minrate=100k
+auto-alt-ref=1
+arnr-maxframes=7
+arnr-strength=5
+arnr-type=centered