encoding xvid in linux from a sequence of images

xvid: you must specify one or a valid combination of 'bitrate', 'pass',
'quantizer' settings

solution:
mencoder mf://*.png -ovc xvid -xvidencopts pass=1 -of avi -o
./tmp/filename.avi

or
mencoder mf://*.png -ovc xvid -xvidencopts bitrate=1600 -of avi -o
./tmp/deneme2.avi