libavcodec/vp3.c:1820: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1812 could be null and is dereferenced by call to `get_bits1()` at line 1820, column 20.

libavcodec/vp3.c:1801:1: start of procedure vp3_decode_frame()
1799.  * This is the ffmpeg/libavcodec API frame decode function.
1800.  */
1801. static int vp3_decode_frame(AVCodecContext *avctx,
      ^
1802.                             void *data, int *data_size,
1803.                             AVPacket *avpkt)

libavcodec/vp3.c:1805:5: 
1803.                             AVPacket *avpkt)
1804. {
1805.     const uint8_t *buf = avpkt->data;
          ^
1806.     int buf_size = avpkt->size;
1807.     Vp3DecodeContext *s = avctx->priv_data;

libavcodec/vp3.c:1806:5: 
1804. {
1805.     const uint8_t *buf = avpkt->data;
1806.     int buf_size = avpkt->size;
          ^
1807.     Vp3DecodeContext *s = avctx->priv_data;
1808.     GetBitContext gb;

libavcodec/vp3.c:1807:5: 
1805.     const uint8_t *buf = avpkt->data;
1806.     int buf_size = avpkt->size;
1807.     Vp3DecodeContext *s = avctx->priv_data;
          ^
1808.     GetBitContext gb;
1809.     static int counter = 0;

libavcodec/vp3.c:1809:5: 
1807.     Vp3DecodeContext *s = avctx->priv_data;
1808.     GetBitContext gb;
1809.     static int counter = 0;
          ^
1810.     int i;
1811. 

libavcodec/vp3.c:1812:5: 
1810.     int i;
1811. 
1812.     init_get_bits(&gb, buf, buf_size * 8);
          ^
1813. 
1814.     if (s->theora && get_bits1(&gb))

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)

libavcodec/vp3.c:1814:9: Taking false branch
1812.     init_get_bits(&gb, buf, buf_size * 8);
1813. 
1814.     if (s->theora && get_bits1(&gb))
              ^
1815.     {
1816.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/vp3.c:1820:20: 
1818.     }
1819. 
1820.     s->keyframe = !get_bits1(&gb);
                         ^
1821.     if (!s->theora)
1822.         skip_bits(&gb, 1);

libavcodec/get_bits.h:416:1: start of procedure get_bits1()
  414. }
  415. 
  416. static inline unsigned int get_bits1(GetBitContext *s){
       ^
  417. #ifdef ALT_BITSTREAM_READER
  418.     int index= s->index;

libavcodec/get_bits.h:418:5: 
  416. static inline unsigned int get_bits1(GetBitContext *s){
  417. #ifdef ALT_BITSTREAM_READER
  418.     int index= s->index;
           ^
  419.     uint8_t result= s->buffer[ index>>3 ];
  420. #ifdef ALT_BITSTREAM_READER_LE

libavcodec/get_bits.h:419:5: 
  417. #ifdef ALT_BITSTREAM_READER
  418.     int index= s->index;
  419.     uint8_t result= s->buffer[ index>>3 ];
           ^
  420. #ifdef ALT_BITSTREAM_READER_LE
  421.     result>>= (index&0x07);
