codecs.conf entry:

videocodec lagarith
  info "Lagarith Lossless Video Codec"
  comment "http://lags.leetcode.net/codec.html"
  status working
  fourcc LAGS
  driver vfw
  dll "lagarith.dll"
  out BGR32,BGR24 flip

the sample was made with virtualdub on windows, but mencoder vfw encoder should be produce the same
output