libavcodec/fmvc.c:152: error: Integer Overflow L1
  ([-7, 0] - 1):unsigned32.

libavcodec/fmvc.c:54:1: <LHS trace>
52. } FMVCContext;
53. 
54. static int decode_type2(GetByteContext *gb, PutByteContext *pb)
    ^
55. {
56.     unsigned repeat = 0, first = 1, opcode;

libavcodec/fmvc.c:54:1: Parameter `*gb->buffer`
52. } FMVCContext;
53. 
54. static int decode_type2(GetByteContext *gb, PutByteContext *pb)
    ^
55. {
56.     unsigned repeat = 0, first = 1, opcode;

libavcodec/fmvc.c:109:26: Call
107.             if (repeat) {
108.                 repeat = 0;
109.                 opcode = bytestream2_peek_byte(gb);
                              ^
110.                 if (opcode < 0x10) {
111.                     bytestream2_skip(gb, 1);

libavcodec/bytestream.h:94:1: Assignment
  92. DEF(unsigned int, be24, 3, AV_RB24, AV_WB24)
  93. DEF(unsigned int, be16, 2, AV_RB16, AV_WB16)
  94. DEF(unsigned int, byte, 1, AV_RB8 , AV_WB8)
      ^
  95. 
  96. #if HAVE_BIGENDIAN

libavcodec/fmvc.c:109:17: Assignment
107.             if (repeat) {
108.                 repeat = 0;
109.                 opcode = bytestream2_peek_byte(gb);
                     ^
110.                 if (opcode < 0x10) {
111.                     bytestream2_skip(gb, 1);

libavcodec/fmvc.c:152:17: Binary operation: ([-7, 0] - 1):unsigned32
150.             if (opcode >= 0x40) {
151.                 bytestream2_skip(gb, 1);
152.                 pos = - ((opcode >> 2) & 7) - 1 - 8 * bytestream2_get_byte(gb);
                     ^
153.                 len =    (opcode >> 5)      - 1;
154. 
