libavcodec/vp3.c:1995: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1993 could be null and is dereferenced by call to `get_bits1()` at line 1995, column 22.

libavcodec/vp3.c:1982:1: start of procedure vp3_decode_frame()
1980. }
1981. 
1982. static int vp3_decode_frame(AVCodecContext *avctx,
      ^
1983.                             void *data, int *got_frame,
1984.                             AVPacket *avpkt)

libavcodec/vp3.c:1986:5: 
1984.                             AVPacket *avpkt)
1985. {
1986.     AVFrame     *frame  = data;
          ^
1987.     const uint8_t *buf  = avpkt->data;
1988.     int buf_size        = avpkt->size;

libavcodec/vp3.c:1987:5: 
1985. {
1986.     AVFrame     *frame  = data;
1987.     const uint8_t *buf  = avpkt->data;
          ^
1988.     int buf_size        = avpkt->size;
1989.     Vp3DecodeContext *s = avctx->priv_data;

libavcodec/vp3.c:1988:5: 
1986.     AVFrame     *frame  = data;
1987.     const uint8_t *buf  = avpkt->data;
1988.     int buf_size        = avpkt->size;
          ^
1989.     Vp3DecodeContext *s = avctx->priv_data;
1990.     GetBitContext gb;

libavcodec/vp3.c:1989:5: 
1987.     const uint8_t *buf  = avpkt->data;
1988.     int buf_size        = avpkt->size;
1989.     Vp3DecodeContext *s = avctx->priv_data;
          ^
1990.     GetBitContext gb;
1991.     int i, ret;

libavcodec/vp3.c:1993:5: 
1991.     int i, ret;
1992. 
1993.     init_get_bits(&gb, buf, buf_size * 8);
          ^
1994. 
1995.     if (s->theora && get_bits1(&gb)) {

libavcodec/get_bits.h:362:1: start of procedure init_get_bits()
  360.  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
  361.  */
  362. static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
       ^
  363.                                 int bit_size)
  364. {

libavcodec/get_bits.h:366:5: 
  364. {
  365.     int buffer_size;
  366.     int ret = 0;
           ^
  367. 
  368.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {

libavcodec/get_bits.h:368:9: Taking true branch
  366.     int ret = 0;
  367. 
  368.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
               ^
  369.         bit_size    = 0;
  370.         buffer      = NULL;

libavcodec/get_bits.h:369:9: 
  367. 
  368.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
  369.         bit_size    = 0;
               ^
  370.         buffer      = NULL;
  371.         ret         = AVERROR_INVALIDDATA;

libavcodec/get_bits.h:370:9: 
  368.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
  369.         bit_size    = 0;
  370.         buffer      = NULL;
               ^
  371.         ret         = AVERROR_INVALIDDATA;
  372.     }

libavcodec/get_bits.h:371:9: 
  369.         bit_size    = 0;
  370.         buffer      = NULL;
  371.         ret         = AVERROR_INVALIDDATA;
               ^
  372.     }
  373. 

libavcodec/get_bits.h:374:5: 
  372.     }
  373. 
  374.     buffer_size = (bit_size + 7) >> 3;
           ^
  375. 
  376.     s->buffer             = buffer;

libavcodec/get_bits.h:376:5: 
  374.     buffer_size = (bit_size + 7) >> 3;
  375. 
  376.     s->buffer             = buffer;
           ^
  377.     s->size_in_bits       = bit_size;
  378. #if !UNCHECKED_BITSTREAM_READER

libavcodec/get_bits.h:377:5: 
  375. 
  376.     s->buffer             = buffer;
  377.     s->size_in_bits       = bit_size;
           ^
  378. #if !UNCHECKED_BITSTREAM_READER
  379.     s->size_in_bits_plus8 = bit_size + 8;

libavcodec/get_bits.h:379:5: 
  377.     s->size_in_bits       = bit_size;
  378. #if !UNCHECKED_BITSTREAM_READER
  379.     s->size_in_bits_plus8 = bit_size + 8;
           ^
  380. #endif
  381.     s->buffer_end         = buffer + buffer_size;

libavcodec/get_bits.h:381:5: 
  379.     s->size_in_bits_plus8 = bit_size + 8;
  380. #endif
  381.     s->buffer_end         = buffer + buffer_size;
           ^
  382.     s->index              = 0;
  383. 

libavcodec/get_bits.h:382:5: 
  380. #endif
  381.     s->buffer_end         = buffer + buffer_size;
  382.     s->index              = 0;
           ^
  383. 
  384.     return ret;

libavcodec/get_bits.h:384:5: 
  382.     s->index              = 0;
  383. 
  384.     return ret;
           ^
  385. }
  386. 

libavcodec/get_bits.h:385:1: return from a call to init_get_bits
  383. 
  384.     return ret;
  385. }
       ^
  386. 
  387. /**

libavcodec/vp3.c:1995:9: Taking true branch
1993.     init_get_bits(&gb, buf, buf_size * 8);
1994. 
1995.     if (s->theora && get_bits1(&gb)) {
              ^
1996.         av_log(avctx, AV_LOG_ERROR,
1997.                "Header packet passed to frame decoder, skipping\n");

libavcodec/vp3.c:1995:22: 
1993.     init_get_bits(&gb, buf, buf_size * 8);
1994. 
1995.     if (s->theora && get_bits1(&gb)) {
                           ^
1996.         av_log(avctx, AV_LOG_ERROR,
1997.                "Header packet passed to frame decoder, skipping\n");

libavcodec/get_bits.h:267:1: start of procedure get_bits1()
  265. }
  266. 
  267. static inline unsigned int get_bits1(GetBitContext *s)
       ^
  268. {
  269.     unsigned int index = s->index;

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

libavcodec/get_bits.h:270:5: 
  268. {
  269.     unsigned int index = s->index;
  270.     uint8_t result     = s->buffer[index >> 3];
           ^
  271. #ifdef BITSTREAM_READER_LE
  272.     result >>= index & 7;
