libavformat/movenc.c:241: error: Null Dereference
  pointer `&gbc->buffer` last assigned on line 240 could be null and is dereferenced by call to `get_bits()` at line 241, column 18.

libavformat/movenc.c:227:1: start of procedure mov_write_ac3_tag()
225. }
226. 
227. static int mov_write_ac3_tag(ByteIOContext *pb, MOVTrack *track)
     ^
228. {
229.     GetBitContext gbc;

libavformat/movenc.c:234:9: Taking false branch
232.     int fscod, bsid, bsmod, acmod, lfeon, frmsizecod;
233. 
234.     if (track->vosLen < 7)
             ^
235.         return -1;
236. 

libavformat/movenc.c:237:5: Skipping put_be32(): empty list of specs
235.         return -1;
236. 
237.     put_be32(pb, 11);
         ^
238.     put_tag(pb, "dac3");
239. 

libavformat/movenc.c:238:5: Skipping put_tag(): empty list of specs
236. 
237.     put_be32(pb, 11);
238.     put_tag(pb, "dac3");
         ^
239. 
240.     init_get_bits(&gbc, track->vosData+4, track->vosLen-4);

libavformat/movenc.c:240:5: 
238.     put_tag(pb, "dac3");
239. 
240.     init_get_bits(&gbc, track->vosData+4, track->vosLen-4);
         ^
241.     fscod      = get_bits(&gbc, 2);
242.     frmsizecod = get_bits(&gbc, 6);

libavcodec/get_bits.h:493:1: start of procedure init_get_bits()
  491.  * @param bit_size the size of the buffer in bits
  492.  */
  493. static inline void init_get_bits(GetBitContext *s,
       ^
  494.                    const uint8_t *buffer, int bit_size)
  495. {

libavcodec/get_bits.h:496:5: 
  494.                    const uint8_t *buffer, int bit_size)
  495. {
  496.     int buffer_size= (bit_size+7)>>3;
           ^
  497.     if(buffer_size < 0 || bit_size < 0) {
  498.         buffer_size = bit_size = 0;

libavcodec/get_bits.h:497:8: Taking true branch
  495. {
  496.     int buffer_size= (bit_size+7)>>3;
  497.     if(buffer_size < 0 || bit_size < 0) {
              ^
  498.         buffer_size = bit_size = 0;
  499.         buffer = NULL;

libavcodec/get_bits.h:498:9: 
  496.     int buffer_size= (bit_size+7)>>3;
  497.     if(buffer_size < 0 || bit_size < 0) {
  498.         buffer_size = bit_size = 0;
               ^
  499.         buffer = NULL;
  500.     }

libavcodec/get_bits.h:499:9: 
  497.     if(buffer_size < 0 || bit_size < 0) {
  498.         buffer_size = bit_size = 0;
  499.         buffer = NULL;
               ^
  500.     }
  501. 

libavcodec/get_bits.h:502:5: 
  500.     }
  501. 
  502.     s->buffer= buffer;
           ^
  503.     s->size_in_bits= bit_size;
  504.     s->buffer_end= buffer + buffer_size;

libavcodec/get_bits.h:503:5: 
  501. 
  502.     s->buffer= buffer;
  503.     s->size_in_bits= bit_size;
           ^
  504.     s->buffer_end= buffer + buffer_size;
  505. #ifdef ALT_BITSTREAM_READER

libavcodec/get_bits.h:504:5: 
  502.     s->buffer= buffer;
  503.     s->size_in_bits= bit_size;
  504.     s->buffer_end= buffer + buffer_size;
           ^
  505. #ifdef ALT_BITSTREAM_READER
  506.     s->index=0;

libavcodec/get_bits.h:506:5: 
  504.     s->buffer_end= buffer + buffer_size;
  505. #ifdef ALT_BITSTREAM_READER
  506.     s->index=0;
           ^
  507. #elif defined LIBMPEG2_BITSTREAM_READER
  508.     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));

libavcodec/get_bits.h:516:1: return from a call to init_get_bits
  514.     skip_bits_long(s, 0);
  515. #endif
  516. }
       ^
  517. 
  518. static inline void align_get_bits(GetBitContext *s)

libavformat/movenc.c:241:5: 
239. 
240.     init_get_bits(&gbc, track->vosData+4, track->vosLen-4);
241.     fscod      = get_bits(&gbc, 2);
         ^
242.     frmsizecod = get_bits(&gbc, 6);
243.     bsid       = get_bits(&gbc, 5);

libavcodec/get_bits.h:385:1: start of procedure get_bits()
  383.  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
  384.  */
  385. static inline unsigned int get_bits(GetBitContext *s, int n){
       ^
  386.     register int tmp;
  387.     OPEN_READER(re, s)

libavcodec/get_bits.h:387:5: 
  385. static inline unsigned int get_bits(GetBitContext *s, int n){
  386.     register int tmp;
  387.     OPEN_READER(re, s)
           ^
  388.     UPDATE_CACHE(re, s)
  389.     tmp= SHOW_UBITS(re, s, n);

libavcodec/get_bits.h:388:5: 
  386.     register int tmp;
  387.     OPEN_READER(re, s)
  388.     UPDATE_CACHE(re, s)
           ^
  389.     tmp= SHOW_UBITS(re, s, n);
  390.     LAST_SKIP_BITS(re, s, n)
