libavcodec/vp3.c:1810: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1808 could be null and is dereferenced by call to `get_bits1()` at line 1810, column 22.

libavcodec/vp3.c:1799:1: start of procedure vp3_decode_frame()
1797.  * This is the ffmpeg/libavcodec API frame decode function.
1798.  */
1799. static int vp3_decode_frame(AVCodecContext *avctx,
      ^
1800.                             void *data, int *data_size,
1801.                             const uint8_t *buf, int buf_size)

libavcodec/vp3.c:1803:5: 
1801.                             const uint8_t *buf, int buf_size)
1802. {
1803.     Vp3DecodeContext *s = avctx->priv_data;
          ^
1804.     GetBitContext gb;
1805.     static int counter = 0;

libavcodec/vp3.c:1805:5: 
1803.     Vp3DecodeContext *s = avctx->priv_data;
1804.     GetBitContext gb;
1805.     static int counter = 0;
          ^
1806.     int i;
1807. 

libavcodec/vp3.c:1808:5: 
1806.     int i;
1807. 
1808.     init_get_bits(&gb, buf, buf_size * 8);
          ^
1809. 
1810.     if (s->theora && get_bits1(&gb))

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/vp3.c:1810:9: Taking true branch
1808.     init_get_bits(&gb, buf, buf_size * 8);
1809. 
1810.     if (s->theora && get_bits1(&gb))
              ^
1811.     {
1812.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/vp3.c:1810:22: 
1808.     init_get_bits(&gb, buf, buf_size * 8);
1809. 
1810.     if (s->theora && get_bits1(&gb))
                           ^
1811.     {
1812.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/bitstream.h:673:1: start of procedure get_bits1()
  671. }
  672. 
  673. static inline unsigned int get_bits1(GetBitContext *s){
       ^
  674. #ifdef ALT_BITSTREAM_READER
  675.     int index= s->index;

libavcodec/bitstream.h:675:5: 
  673. static inline unsigned int get_bits1(GetBitContext *s){
  674. #ifdef ALT_BITSTREAM_READER
  675.     int index= s->index;
           ^
  676.     uint8_t result= s->buffer[ index>>3 ];
  677. #ifdef ALT_BITSTREAM_READER_LE

libavcodec/bitstream.h:676:5: 
  674. #ifdef ALT_BITSTREAM_READER
  675.     int index= s->index;
  676.     uint8_t result= s->buffer[ index>>3 ];
           ^
  677. #ifdef ALT_BITSTREAM_READER_LE
  678.     result>>= (index&0x07);
