I'm trying to encode one wmv video to VP9 with FFMPEG and it completely ignores set bitrate and it just keeps increasing. It starts at 5000kbit/s and ends at 11000kbit/s 
@matrix Are you trying to have the resulting video of a specific size or why does the bitrate have to be specific?
@pigfarmer The original is 1500kbit/s
@matrix @pigfarmer Try setting the -minrate and -maxrate. It should limit the bitrate.
@PHNT @pigfarmer Looks like setting a constant bitrate helps