libavcodec/mpc8.c:204: error: Null Dereference
  pointer `gb->buffer` last assigned on line 203 could be null and is dereferenced by call to `skip_bits()` at line 204, column 5.

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

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

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

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

libavcodec/mpc8.c:197:16: Condition is false
195.     int last[2];
196. 
197.     keyframe = c->cur_frame == 0;
                    ^
198. 
199.     if(keyframe){

libavcodec/mpc8.c:197:5: 
195.     int last[2];
196. 
197.     keyframe = c->cur_frame == 0;
         ^
198. 
199.     if(keyframe){

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

libavcodec/mpc8.c:203:5: 
201.         c->last_bits_used = 0;
202.     }
203.     init_get_bits(gb, buf, buf_size * 8);
         ^
204.     skip_bits(gb, c->last_bits_used & 7);
205. 

libavcodec/bitstream.h:745:1: start of procedure init_get_bits()
  743.  * @param bit_size the size of the buffer in bits
  744.  */
  745. static inline void init_get_bits(GetBitContext *s,
       ^
  746.                    const uint8_t *buffer, int bit_size)
  747. {

libavcodec/bitstream.h:748:5: 
  746.                    const uint8_t *buffer, int bit_size)
  747. {
  748.     int buffer_size= (bit_size+7)>>3;
           ^
  749.     if(buffer_size < 0 || bit_size < 0) {
  750.         buffer_size = bit_size = 0;

libavcodec/bitstream.h:749:8: Taking true branch
  747. {
  748.     int buffer_size= (bit_size+7)>>3;
  749.     if(buffer_size < 0 || bit_size < 0) {
              ^
  750.         buffer_size = bit_size = 0;
  751.         buffer = NULL;

libavcodec/bitstream.h:750:9: 
  748.     int buffer_size= (bit_size+7)>>3;
  749.     if(buffer_size < 0 || bit_size < 0) {
  750.         buffer_size = bit_size = 0;
               ^
  751.         buffer = NULL;
  752.     }

libavcodec/bitstream.h:751:9: 
  749.     if(buffer_size < 0 || bit_size < 0) {
  750.         buffer_size = bit_size = 0;
  751.         buffer = NULL;
               ^
  752.     }
  753. 

libavcodec/bitstream.h:754:5: 
  752.     }
  753. 
  754.     s->buffer= buffer;
           ^
  755.     s->size_in_bits= bit_size;
  756.     s->buffer_end= buffer + buffer_size;

libavcodec/bitstream.h:755:5: 
  753. 
  754.     s->buffer= buffer;
  755.     s->size_in_bits= bit_size;
           ^
  756.     s->buffer_end= buffer + buffer_size;
  757. #ifdef ALT_BITSTREAM_READER

libavcodec/bitstream.h:756:5: 
  754.     s->buffer= buffer;
  755.     s->size_in_bits= bit_size;
  756.     s->buffer_end= buffer + buffer_size;
           ^
  757. #ifdef ALT_BITSTREAM_READER
  758.     s->index=0;

libavcodec/bitstream.h:758:5: 
  756.     s->buffer_end= buffer + buffer_size;
  757. #ifdef ALT_BITSTREAM_READER
  758.     s->index=0;
           ^
  759. #elif defined LIBMPEG2_BITSTREAM_READER
  760.     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));

libavcodec/bitstream.h:768:1: return from a call to init_get_bits
  766.     skip_bits_long(s, 0);
  767. #endif
  768. }
       ^
  769. 
  770. static inline void align_get_bits(GetBitContext *s)

libavcodec/mpc8.c:204:5: 
202.     }
203.     init_get_bits(gb, buf, buf_size * 8);
204.     skip_bits(gb, c->last_bits_used & 7);
         ^
205. 
206.     if(keyframe)

libavcodec/bitstream.h:665:1: start of procedure skip_bits()
  663. }
  664. 
  665. static inline void skip_bits(GetBitContext *s, int n){
       ^
  666.  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
  667.     OPEN_READER(re, s)

libavcodec/bitstream.h:667:5: 
  665. static inline void skip_bits(GetBitContext *s, int n){
  666.  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
  667.     OPEN_READER(re, s)
           ^
  668.     UPDATE_CACHE(re, s)
  669.     LAST_SKIP_BITS(re, s, n)

libavcodec/bitstream.h:668:5: 
  666.  //Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
  667.     OPEN_READER(re, s)
  668.     UPDATE_CACHE(re, s)
           ^
  669.     LAST_SKIP_BITS(re, s, n)
  670.     CLOSE_READER(re, s)
