How to use NVENC with AVCONV in Ubuntu?

i’m encoding my videos using libx264 with avconv under Ubuntu:

avconv -c:v libx264 -preset slower …

I would like to know how to use in avconv,
because I can’t get it to work!

Is it possible? I need it because I’t not frendly to use NVEncoder
especially because the source is a .DV and I need to applay
a yadif filter while doing the conversion.

Thank you!