libavcodec/fmvc.c:221: error: Uninitialized Value
  The value read from opcode was never initialized.

libavcodec/fmvc.c:221:13: 
219.         }
220.         bytestream2_skip(gb, 1);
221.         if (opcode < 0x10) {
                 ^
222.             pos = -(opcode >> 2) - 1 - 4 * bytestream2_get_byte(gb);
223. 
