[FFmpeg-user] Which parameter for WEBM VP8/Vorbis quality depending on resolution?

[tag at gmx.com]

Tom Evans wrote:
> You can use the -crf argument, which sets a quality setting for the
> final video, not a bitrate. I believe this works with libvpx.

ffmpeg -i 12082012.mp4 -crf 10 12082012.mp4_crf10.webm
ffmpeg -i 12082012.mp4 -crf 20 12082012.mp4_crf20.webm
ffmpeg -i 12082012.mp4 -crf 40 12082012.mp4_crf40.webm

-crf 10: Filesize 11716 KB
-crf 20: Filesize 11716 KB
-crf 40: Filesize 11716 KB

Seems it does not work. Default 200 kb/s stays active all the time.

Are there other options?