mencoder: discarding every 2nd frames

[nexx]

I have some progressive 50fps material. Every second frame is just a duplicate so it would be unnessasery to encode these. I am after a way to drop every second frame and give 25fps output.
It seems possible with the decimate filter, but I havent any luck with various settings.

Suggestions?

[mean]

-ofps 25
?

[nexx]

well then...that does make things easy :cool:
I thought -ofps 25 would leave me with file at 50% speed.

Thanks.