libavcodec/vc1_parser.c:200: error: Uninitialized Value
  The value read from b was never initialized.

libavcodec/vc1_parser.c:200:68: 
198. 
199.             if (!(s->flags & PARSER_FLAG_COMPLETE_FRAMES)) {
200.                 if (!pic_found && (b == (VC1_CODE_FRAME & 0xFF) || b == (VC1_CODE_FIELD & 0xFF))) {
                                                                        ^
201.                     pic_found = 1;
202.                 }
