webm libvpx-vp9 # YOUTUBE - Ultra High Definition video # More VP9 options if choose format of webm # Refer to section 3.4 in Features5.pdf # 3840x2160 (50 or 60 frames per second) bitrate=18000k minrate=9000k maxrate=26100k tile-columns=4 g=240 threads=24 quality=good crf=15 speed=4