libavcodec/mlpdec.c:1018: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1016 could be null and is dereferenced by call to `show_bits_long()` at line 1018, column 9.

libavcodec/mlpdec.c:995:1: start of procedure read_access_unit()
993.  *  otherwise returns the number of bytes consumed. */
994. 
995. static int read_access_unit(AVCodecContext *avctx, void* data, int *data_size,
     ^
996.                             const uint8_t *buf, int buf_size)
997. {

libavcodec/mlpdec.c:998:5: 
 996.                             const uint8_t *buf, int buf_size)
 997. {
 998.     MLPDecodeContext *m = avctx->priv_data;
          ^
 999.     GetBitContext gb;
1000.     unsigned int length, substr;

libavcodec/mlpdec.c:1002:5: 
1000.     unsigned int length, substr;
1001.     unsigned int substream_start;
1002.     unsigned int header_size = 4;
          ^
1003.     unsigned int substr_header_size = 0;
1004.     uint8_t substream_parity_present[MAX_SUBSTREAMS];

libavcodec/mlpdec.c:1003:5: 
1001.     unsigned int substream_start;
1002.     unsigned int header_size = 4;
1003.     unsigned int substr_header_size = 0;
          ^
1004.     uint8_t substream_parity_present[MAX_SUBSTREAMS];
1005.     uint16_t substream_data_len[MAX_SUBSTREAMS];

libavcodec/mlpdec.c:1008:9: Taking false branch
1006.     uint8_t parity_bits;
1007. 
1008.     if (buf_size < 4)
              ^
1009.         return 0;
1010. 

libavcodec/mlpdec.c:1011:5: 
1009.         return 0;
1010. 
1011.     length = (AV_RB16(buf) & 0xfff) * 2;
          ^
1012. 
1013.     if (length > buf_size)

libavcodec/mlpdec.c:1013:9: Taking false branch
1011.     length = (AV_RB16(buf) & 0xfff) * 2;
1012. 
1013.     if (length > buf_size)
              ^
1014.         return -1;
1015. 

libavcodec/mlpdec.c:1016:5: 
1014.         return -1;
1015. 
1016.     init_get_bits(&gb, (buf + 4), (length - 4) * 8);
          ^
1017. 
1018.     if (show_bits_long(&gb, 31) == (0xf8726fba >> 1)) {

libavcodec/bitstream.h:719:1: start of procedure init_get_bits()
  717.  * @param bit_size the size of the buffer in bits
  718.  */
  719. static inline void init_get_bits(GetBitContext *s,
       ^
  720.                    const uint8_t *buffer, int bit_size)
  721. {

libavcodec/bitstream.h:722:5: 
  720.                    const uint8_t *buffer, int bit_size)
  721. {
  722.     int buffer_size= (bit_size+7)>>3;
           ^
  723.     if(buffer_size < 0 || bit_size < 0) {
  724.         buffer_size = bit_size = 0;

libavcodec/bitstream.h:723:8: Taking true branch
  721. {
  722.     int buffer_size= (bit_size+7)>>3;
  723.     if(buffer_size < 0 || bit_size < 0) {
              ^
  724.         buffer_size = bit_size = 0;
  725.         buffer = NULL;

libavcodec/bitstream.h:724:9: 
  722.     int buffer_size= (bit_size+7)>>3;
  723.     if(buffer_size < 0 || bit_size < 0) {
  724.         buffer_size = bit_size = 0;
               ^
  725.         buffer = NULL;
  726.     }

libavcodec/bitstream.h:725:9: 
  723.     if(buffer_size < 0 || bit_size < 0) {
  724.         buffer_size = bit_size = 0;
  725.         buffer = NULL;
               ^
  726.     }
  727. 

libavcodec/bitstream.h:728:5: 
  726.     }
  727. 
  728.     s->buffer= buffer;
           ^
  729.     s->size_in_bits= bit_size;
  730.     s->buffer_end= buffer + buffer_size;

libavcodec/bitstream.h:729:5: 
  727. 
  728.     s->buffer= buffer;
  729.     s->size_in_bits= bit_size;
           ^
  730.     s->buffer_end= buffer + buffer_size;
  731. #ifdef ALT_BITSTREAM_READER

libavcodec/bitstream.h:730:5: 
  728.     s->buffer= buffer;
  729.     s->size_in_bits= bit_size;
  730.     s->buffer_end= buffer + buffer_size;
           ^
  731. #ifdef ALT_BITSTREAM_READER
  732.     s->index=0;

libavcodec/bitstream.h:732:5: 
  730.     s->buffer_end= buffer + buffer_size;
  731. #ifdef ALT_BITSTREAM_READER
  732.     s->index=0;
           ^
  733. #elif defined LIBMPEG2_BITSTREAM_READER
  734.     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));

libavcodec/bitstream.h:742:1: return from a call to init_get_bits
  740.     skip_bits_long(s, 0);
  741. #endif
  742. }
       ^
  743. 
  744. static inline void align_get_bits(GetBitContext *s)

libavcodec/mlpdec.c:1018:9: 
1016.     init_get_bits(&gb, (buf + 4), (length - 4) * 8);
1017. 
1018.     if (show_bits_long(&gb, 31) == (0xf8726fba >> 1)) {
              ^
1019.         dprintf(m->avctx, "Found major sync.\n");
1020.         if (read_major_sync(m, &gb) < 0)

libavcodec/bitstream.h:694:1: start of procedure show_bits_long()
  692.  * shows 0-32 bits.
  693.  */
  694. static inline unsigned int show_bits_long(GetBitContext *s, int n){
       ^
  695.     if(n<=17) return show_bits(s, n);
  696.     else{

libavcodec/bitstream.h:695:8: Taking true branch
  693.  */
  694. static inline unsigned int show_bits_long(GetBitContext *s, int n){
  695.     if(n<=17) return show_bits(s, n);
              ^
  696.     else{
  697.         GetBitContext gb= *s;

libavcodec/bitstream.h:695:15: 
  693.  */
  694. static inline unsigned int show_bits_long(GetBitContext *s, int n){
  695.     if(n<=17) return show_bits(s, n);
                     ^
  696.     else{
  697.         GetBitContext gb= *s;

libavcodec/bitstream.h:630:1: start of procedure show_bits()
    628.  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
    629.  */
    630. static inline unsigned int show_bits(GetBitContext *s, int n){
         ^
    631.     register int tmp;
    632.     OPEN_READER(re, s)

libavcodec/bitstream.h:632:5: 
    630. static inline unsigned int show_bits(GetBitContext *s, int n){
    631.     register int tmp;
    632.     OPEN_READER(re, s)
             ^
    633.     UPDATE_CACHE(re, s)
    634.     tmp= SHOW_UBITS(re, s, n);

libavcodec/bitstream.h:633:5: 
    631.     register int tmp;
    632.     OPEN_READER(re, s)
    633.     UPDATE_CACHE(re, s)
             ^
    634.     tmp= SHOW_UBITS(re, s, n);
    635. //    CLOSE_READER(re, s)
