avconv.c:4183: error: Uninitialized Value
  The value read from ost was never initialized.

avconv.c:4183:5: 
4181.     ost->filter       = ofilter;
4182. 
4183.     ofilter->ost      = ost;
          ^
4184. 
4185.     if (ost->stream_copy) {
