Duplicate frame(s) when using mencoder

I saw:

Pos: 538.9s   2183f (92%) 141.77fps Trem:   0min   6mb  A-V:0.000 [91:0]
1 duplicate frame(s)!
Pos: 540.7s   2208f (92%) 142.08fps Trem:   0min   6mb  A-V:0.000 [91:0]
1 duplicate frame(s)!

when I used mencoder.

I solved this problem with this option called noskip:



mencoder -noskip file.ogv -ovc lavc -o file.avi

The line above turned an ogv file into an avi file.