[FFmpeg-user] FFMPEG constant bitrate with libvpx on FreeBSD 9

[Manas Bhatnagar]

Hello. I am running ffmpeg version 2.1.1. I am trying to convert a h264,ac3
.mkv to a vp8,ogg .webm file with constant bitrate. the command I am using
is "ffmpeg -i video.mkv -c:v libvpx -b:v 450k -minrate 450k -maxrate 450k
-c:a libvorbis -b:a 48k -ac 2 video.webm". the output video file that is
produced always has a very high bitrate (1000+kbps). I would like some help
with making ffmpeg produce a constant bitrate file. the source file has a
size of 1280x714 and I am not altering that.