When I run that command, I get this as return:

Code:
MEncoder dev-SVN-r24142-3.4.6 (C) 2000-2007 MPlayer Team
CPU: Intel(R) Celeron(R) CPU 3.06GHz (Family: 15, Model: 4, Stepping: 9)
CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled for x86 CPU with extensions: MMX MMX2 SSE SSE2

Option lavfopts: Unknown suboption i_certify_that_my_video_stream_does_not_use_b_frames
Error parsing option on the command line: -lavfopts

Exiting... (error parsing command line)