libavcodec/mpc8.c:202: error: Null Dereference
  pointer `gb->buffer` last assigned on line 201 could be null and is dereferenced by call to `skip_bits()` at line 202, column 5.

libavcodec/mpc8.c:183:1: start of procedure mpc8_decode_frame()
181. }
182. 
183. static int mpc8_decode_frame(AVCodecContext * avctx,
     ^
184.                             void *data, int *data_size,
185.                             const uint8_t * buf, int buf_size)

libavcodec/mpc8.c:187:5: 
185.                             const uint8_t * buf, int buf_size)
186. {
187.     MPCContext *c = avctx->priv_data;
         ^
188.     GetBitContext gb2, *gb = &gb2;
189.     int i, j, k, ch, cnt, res, t;

libavcodec/mpc8.c:188:5: 
186. {
187.     MPCContext *c = avctx->priv_data;
188.     GetBitContext gb2, *gb = &gb2;
         ^
189.     int i, j, k, ch, cnt, res, t;
190.     Band *bands = c->bands;

libavcodec/mpc8.c:190:5: 
188.     GetBitContext gb2, *gb = &gb2;
189.     int i, j, k, ch, cnt, res, t;
190.     Band *bands = c->bands;
         ^
191.     int off;
192.     int maxband, keyframe;

libavcodec/mpc8.c:195:16: Condition is true
193.     int last[2];
194. 
195.     keyframe = c->cur_frame == 0;
                    ^
196. 
197.     if(keyframe){

libavcodec/mpc8.c:195:5: 
193.     int last[2];
194. 
195.     keyframe = c->cur_frame == 0;
         ^
196. 
197.     if(keyframe){

libavcodec/mpc8.c:197:8: Taking true branch
195.     keyframe = c->cur_frame == 0;
196. 
197.     if(keyframe){
            ^
198.         memset(c->Q, 0, sizeof(c->Q));
199.         c->last_bits_used = 0;

libavcodec/mpc8.c:198:9: 
196. 
197.     if(keyframe){
198.         memset(c->Q, 0, sizeof(c->Q));
             ^
199.         c->last_bits_used = 0;
200.     }

libavcodec/mpc8.c:199:9: 
197.     if(keyframe){
198.         memset(c->Q, 0, sizeof(c->Q));
199.         c->last_bits_used = 0;
             ^
200.     }
201.     init_get_bits(gb, buf, buf_size * 8);

libavcodec/mpc8.c:201:5: 
199.         c->last_bits_used = 0;
200.     }
201.     init_get_bits(gb, buf, buf_size * 8);
         ^
202.     skip_bits(gb, c->last_bits_used & 7);
203. 

libavcodec/bitstream.h:758:1: start of procedure init_get_bits()
  756.  * @param bit_size the size of the buffer in bits
  757.  */
  758. static inline void init_get_bits(GetBitContext *s,
       ^
  759.                    const uint8_t *buffer, int bit_size)
  760. {

libavcodec/bitstream.h:761:5: 
  759.                    const uint8_t *buffer, int bit_size)
  760. {
  761.     int buffer_size= (bit_size+7)>>3;
           ^
  762.     if(buffer_size < 0 || bit_size < 0) {
  763.         buffer_size = bit_size = 0;

libavcodec/bitstream.h:762:8: Taking true branch
  760. {
  761.     int buffer_size= (bit_size+7)>>3;
  762.     if(buffer_size < 0 || bit_size < 0) {
              ^
  763.         buffer_size = bit_size = 0;
  764.         buffer = NULL;

libavcodec/bitstream.h:763:9: 
  761.     int buffer_size= (bit_size+7)>>3;
  762.     if(buffer_size < 0 || bit_size < 0) {
  763.         buffer_size = bit_size = 0;
               ^
  764.         buffer = NULL;
  765.     }

libavcodec/bitstream.h:764:9: 
  762.     if(buffer_size < 0 || bit_size < 0) {
  763.         buffer_size = bit_size = 0;
  764.         buffer = NULL;
               ^
  765.     }
  766. 

libavcodec/bitstream.h:767:5: 
  765.     }
  766. 
  767.     s->buffer= buffer;
           ^
  768.     s->size_in_bits= bit_size;
  769.     s->buffer_end= buffer + buffer_size;

libavcodec/bitstream.h:768:5: 
  766. 
  767.     s->buffer= buffer;
  768.     s->size_in_bits= bit_size;
           ^
  769.     s->buffer_end= buffer + buffer_size;
  770. #ifdef ALT_BITSTREAM_READER

libavcodec/bitstream.h:769:5: 
  767.     s->buffer= buffer;
  768.     s->size_in_bits= bit_size;
  769.     s->buffer_end= buffer + buffer_size;
           ^
  770. #ifdef ALT_BITSTREAM_READER
  771.     s->index=0;

libavcodec/bitstream.h:771:5: 
  769.     s->buffer_end= buffer + buffer_size;
  770. #ifdef ALT_BITSTREAM_READER
  771.     s->index=0;
           ^
  772. #elif defined LIBMPEG2_BITSTREAM_READER
  773.     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));

libavcodec/bitstream.h:781:1: return from a call to init_get_bits
  779.     skip_bits_long(s, 0);
  780. #endif
  781. }
       ^
  782. 
  783. static inline void align_get_bits(GetBitContext *s)

libavcodec/mpc8.c:202:5: 
200.     }
201.     init_get_bits(gb, buf, buf_size * 8);
202.     skip_bits(gb, c->last_bits_used & 7);
         ^
203. 
204.     if(keyframe)

libavcodec/bitstream.h:678:1: start of procedure skip_bits()
  676. }
  677. 
  678. static inline void skip_bits(GetBitContext *s, int n){
       ^
  679.  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
  680.     OPEN_READER(re, s)

libavcodec/bitstream.h:680:5: 
  678. static inline void skip_bits(GetBitContext *s, int n){
  679.  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
  680.     OPEN_READER(re, s)
           ^
  681.     UPDATE_CACHE(re, s)
  682.     LAST_SKIP_BITS(re, s, n)

libavcodec/bitstream.h:681:5: 
  679.  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
  680.     OPEN_READER(re, s)
  681.     UPDATE_CACHE(re, s)
           ^
  682.     LAST_SKIP_BITS(re, s, n)
  683.     CLOSE_READER(re, s)
