" [ -consumer id[:arg] [ name=value ]* ]\n"
" [ -filter filter[:arg] [ name=value ] * ]\n"
" [ -attach filter[:arg] [ name=value ] * ]\n"
+ " [ -mix length [ -mixer transition ]* ]\n"
" [ -transition id[:arg] [ name=value ] * ]\n"
" [ -blank frames ]\n"
" [ -track ]\n"