for name [ [ in [ word ... ] ] ; ] do list ; done
       The  list of words following in is expanded, generating a list of items.  The variable name is set
       to each element of this list in turn, and list is executed each time.  If the in word is  omitted,
       the  for  command  executes  list  once  for each positional parameter that is set (see PARAMETERS
       below).  The return status is the exit status of the last command that executes.  If the expansion
       of  the  items  following  in  results  in an empty list, no commands are executed, and the return
       status is 0.

ffmpeg video converter

-i filename
    input file name

-acodec codec
    Force audio codec to codec. Use the "copy" special value to specify that the raw codec data must be
    copied as is.