libavcodec/vp3.c:1924: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1922 could be null and is dereferenced by call to `get_bits1()` at line 1924, column 22.

libavcodec/vp3.c:1912:1: start of procedure vp3_decode_frame()
1910. }
1911. 
1912. static int vp3_decode_frame(AVCodecContext *avctx,
      ^
1913.                             void *data, int *got_frame,
1914.                             AVPacket *avpkt)

libavcodec/vp3.c:1916:5: 
1914.                             AVPacket *avpkt)
1915. {
1916.     const uint8_t *buf = avpkt->data;
          ^
1917.     int buf_size = avpkt->size;
1918.     Vp3DecodeContext *s = avctx->priv_data;

libavcodec/vp3.c:1917:5: 
1915. {
1916.     const uint8_t *buf = avpkt->data;
1917.     int buf_size = avpkt->size;
          ^
1918.     Vp3DecodeContext *s = avctx->priv_data;
1919.     GetBitContext gb;

libavcodec/vp3.c:1918:5: 
1916.     const uint8_t *buf = avpkt->data;
1917.     int buf_size = avpkt->size;
1918.     Vp3DecodeContext *s = avctx->priv_data;
          ^
1919.     GetBitContext gb;
1920.     int i;

libavcodec/vp3.c:1922:5: 
1920.     int i;
1921. 
1922.     init_get_bits(&gb, buf, buf_size * 8);
          ^
1923. 
1924.     if (s->theora && get_bits1(&gb))

libavcodec/get_bits.h:352:1: start of procedure init_get_bits()
  350.  * @param bit_size the size of the buffer in bits
  351.  */
  352. static inline void init_get_bits(GetBitContext *s, const uint8_t *buffer,
       ^
  353.                                  int bit_size)
  354. {

libavcodec/get_bits.h:355:5: 
  353.                                  int bit_size)
  354. {
  355.     int buffer_size = (bit_size+7)>>3;
           ^
  356.     if (buffer_size < 0 || bit_size < 0) {
  357.         buffer_size = bit_size = 0;

libavcodec/get_bits.h:356:9: Taking true branch
  354. {
  355.     int buffer_size = (bit_size+7)>>3;
  356.     if (buffer_size < 0 || bit_size < 0) {
               ^
  357.         buffer_size = bit_size = 0;
  358.         buffer = NULL;

libavcodec/get_bits.h:357:9: 
  355.     int buffer_size = (bit_size+7)>>3;
  356.     if (buffer_size < 0 || bit_size < 0) {
  357.         buffer_size = bit_size = 0;
               ^
  358.         buffer = NULL;
  359.     }

libavcodec/get_bits.h:358:9: 
  356.     if (buffer_size < 0 || bit_size < 0) {
  357.         buffer_size = bit_size = 0;
  358.         buffer = NULL;
               ^
  359.     }
  360. 

libavcodec/get_bits.h:361:5: 
  359.     }
  360. 
  361.     s->buffer       = buffer;
           ^
  362.     s->size_in_bits = bit_size;
  363. #if !UNCHECKED_BITSTREAM_READER

libavcodec/get_bits.h:362:5: 
  360. 
  361.     s->buffer       = buffer;
  362.     s->size_in_bits = bit_size;
           ^
  363. #if !UNCHECKED_BITSTREAM_READER
  364.     s->size_in_bits_plus8 = bit_size + 8;

libavcodec/get_bits.h:364:5: 
  362.     s->size_in_bits = bit_size;
  363. #if !UNCHECKED_BITSTREAM_READER
  364.     s->size_in_bits_plus8 = bit_size + 8;
           ^
  365. #endif
  366.     s->buffer_end   = buffer + buffer_size;

libavcodec/get_bits.h:366:5: 
  364.     s->size_in_bits_plus8 = bit_size + 8;
  365. #endif
  366.     s->buffer_end   = buffer + buffer_size;
           ^
  367.     s->index        = 0;
  368. }

libavcodec/get_bits.h:367:5: 
  365. #endif
  366.     s->buffer_end   = buffer + buffer_size;
  367.     s->index        = 0;
           ^
  368. }
  369. 

libavcodec/get_bits.h:368:1: return from a call to init_get_bits
  366.     s->buffer_end   = buffer + buffer_size;
  367.     s->index        = 0;
  368. }
       ^
  369. 
  370. static inline void align_get_bits(GetBitContext *s)

libavcodec/vp3.c:1924:9: Taking true branch
1922.     init_get_bits(&gb, buf, buf_size * 8);
1923. 
1924.     if (s->theora && get_bits1(&gb))
              ^
1925.     {
1926.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/vp3.c:1924:22: 
1922.     init_get_bits(&gb, buf, buf_size * 8);
1923. 
1924.     if (s->theora && get_bits1(&gb))
                           ^
1925.     {
1926.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/get_bits.h:268:1: start of procedure get_bits1()
  266. }
  267. 
  268. static inline unsigned int get_bits1(GetBitContext *s)
       ^
  269. {
  270.     unsigned int index = s->index;

libavcodec/get_bits.h:270:5: 
  268. static inline unsigned int get_bits1(GetBitContext *s)
  269. {
  270.     unsigned int index = s->index;
           ^
  271.     uint8_t result = s->buffer[index>>3];
  272. #ifdef BITSTREAM_READER_LE

libavcodec/get_bits.h:271:5: 
  269. {
  270.     unsigned int index = s->index;
  271.     uint8_t result = s->buffer[index>>3];
           ^
  272. #ifdef BITSTREAM_READER_LE
  273.     result >>= index & 7;
