mencoder mf://*.jpg -mf w=800:h=600:fps=25:type=jpg -ovc lavc \
    -lavcopts vcodec=mpeg4:mbd=2:trell -oac copy -o output.avi

ffmpeg -i output.avi -vf "movie=my_ogo.png [logo];[in][logo] overlay=W-w-10:H-h-10 [out]" -vcodec libx264 output\your_output.mp4