libavcodec/vp3.c:2150: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 2142 could be null and is dereferenced by call to `get_bits1()` at line 2150, column 20.

libavcodec/vp3.c:2133:1: start of procedure vp3_decode_frame()
2131.  * This is the ffmpeg/libavcodec API frame decode function.
2132.  */
2133. static int vp3_decode_frame(AVCodecContext *avctx,
      ^
2134.                             void *data, int *data_size,
2135.                             const uint8_t *buf, int buf_size)

libavcodec/vp3.c:2137:5: 
2135.                             const uint8_t *buf, int buf_size)
2136. {
2137.     Vp3DecodeContext *s = avctx->priv_data;
          ^
2138.     GetBitContext gb;
2139.     static int counter = 0;

libavcodec/vp3.c:2139:5: 
2137.     Vp3DecodeContext *s = avctx->priv_data;
2138.     GetBitContext gb;
2139.     static int counter = 0;
          ^
2140.     int i;
2141. 

libavcodec/vp3.c:2142:5: 
2140.     int i;
2141. 
2142.     init_get_bits(&gb, buf, buf_size * 8);
          ^
2143. 
2144.     if (s->theora && get_bits1(&gb))

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/vp3.c:2144:9: Taking false branch
2142.     init_get_bits(&gb, buf, buf_size * 8);
2143. 
2144.     if (s->theora && get_bits1(&gb))
              ^
2145.     {
2146.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/vp3.c:2150:20: 
2148.     }
2149. 
2150.     s->keyframe = !get_bits1(&gb);
                         ^
2151.     if (!s->theora)
2152.         skip_bits(&gb, 1);

libavcodec/bitstream.h:647:1: start of procedure get_bits1()
  645. }
  646. 
  647. static inline unsigned int get_bits1(GetBitContext *s){
       ^
  648. #ifdef ALT_BITSTREAM_READER
  649.     int index= s->index;

libavcodec/bitstream.h:649:5: 
  647. static inline unsigned int get_bits1(GetBitContext *s){
  648. #ifdef ALT_BITSTREAM_READER
  649.     int index= s->index;
           ^
  650.     uint8_t result= s->buffer[ index>>3 ];
  651. #ifdef ALT_BITSTREAM_READER_LE

libavcodec/bitstream.h:650:5: 
  648. #ifdef ALT_BITSTREAM_READER
  649.     int index= s->index;
  650.     uint8_t result= s->buffer[ index>>3 ];
           ^
  651. #ifdef ALT_BITSTREAM_READER_LE
  652.     result>>= (index&0x07);
