[FFmpeg-user] How to re-encode 3d video to 2d video

[jd1008]

Is this the way to convert a 3d vid to 2d?

Moritz had replied to another question of how to play 3d vid on computers
not capable of playing 3d. So I used his -vf options as follows:

ffmpeg -i the_3d_video.mp4 -r 29  -vf 
"crop=w=iw/2:h=ih:x=0:y=0,scale=w=2*iw:h=ih,setdar=2"  -y the_2d_video.mp4

The command above is still running, and will likely take hours on my 
slow computer.

P.S. using ffmpeg-2.1.8-1.fc20.x86_64
because this computer is stuck at fc20 and upgrading to fc23 breaks 
other things.

Thanx!