avconv.c:609: error: Uninitialized Value
  The value read from ist was never initialized.

avconv.c:609:5: 
607.     if (!(fg->inputs[fg->nb_inputs - 1] = av_mallocz(sizeof(*fg->inputs[0]))))
608.         exit_program(1);
609.     fg->inputs[fg->nb_inputs - 1]->ist   = ist;
         ^
610.     fg->inputs[fg->nb_inputs - 1]->graph = fg;
611. 
