libavcodec/vp3.c:1956: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1954 could be null and is dereferenced by call to `get_bits1()` at line 1956, column 22.

libavcodec/vp3.c:1944:1: start of procedure vp3_decode_frame()
1942. }
1943. 
1944. static int vp3_decode_frame(AVCodecContext *avctx,
      ^
1945.                             void *data, int *got_frame,
1946.                             AVPacket *avpkt)

libavcodec/vp3.c:1948:5: 
1946.                             AVPacket *avpkt)
1947. {
1948.     const uint8_t *buf = avpkt->data;
          ^
1949.     int buf_size = avpkt->size;
1950.     Vp3DecodeContext *s = avctx->priv_data;

libavcodec/vp3.c:1949:5: 
1947. {
1948.     const uint8_t *buf = avpkt->data;
1949.     int buf_size = avpkt->size;
          ^
1950.     Vp3DecodeContext *s = avctx->priv_data;
1951.     GetBitContext gb;

libavcodec/vp3.c:1950:5: 
1948.     const uint8_t *buf = avpkt->data;
1949.     int buf_size = avpkt->size;
1950.     Vp3DecodeContext *s = avctx->priv_data;
          ^
1951.     GetBitContext gb;
1952.     int i, ret;

libavcodec/vp3.c:1954:5: 
1952.     int i, ret;
1953. 
1954.     init_get_bits(&gb, buf, buf_size * 8);
          ^
1955. 
1956.     if (s->theora && get_bits1(&gb))

libavcodec/get_bits.h:375:1: start of procedure init_get_bits()
  373.  * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
  374.  */
  375. static inline int init_get_bits(GetBitContext *s, const uint8_t *buffer,
       ^
  376.                                 int bit_size)
  377. {

libavcodec/get_bits.h:379:5: 
  377. {
  378.     int buffer_size;
  379.     int ret = 0;
           ^
  380. 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {

libavcodec/get_bits.h:381:9: Taking true branch
  379.     int ret = 0;
  380. 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
               ^
  382.         buffer_size = bit_size = 0;
  383.         buffer      = NULL;

libavcodec/get_bits.h:382:9: 
  380. 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
  382.         buffer_size = bit_size = 0;
               ^
  383.         buffer      = NULL;
  384.         ret         = AVERROR_INVALIDDATA;

libavcodec/get_bits.h:383:9: 
  381.     if (bit_size > INT_MAX - 7 || bit_size < 0 || !buffer) {
  382.         buffer_size = bit_size = 0;
  383.         buffer      = NULL;
               ^
  384.         ret         = AVERROR_INVALIDDATA;
  385.     }

libavcodec/get_bits.h:384:9: 
  382.         buffer_size = bit_size = 0;
  383.         buffer      = NULL;
  384.         ret         = AVERROR_INVALIDDATA;
               ^
  385.     }
  386. 

libavcodec/get_bits.h:387:5: 
  385.     }
  386. 
  387.     buffer_size = (bit_size + 7) >> 3;
           ^
  388. 
  389.     s->buffer             = buffer;

libavcodec/get_bits.h:389:5: 
  387.     buffer_size = (bit_size + 7) >> 3;
  388. 
  389.     s->buffer             = buffer;
           ^
  390.     s->size_in_bits       = bit_size;
  391. #if !UNCHECKED_BITSTREAM_READER

libavcodec/get_bits.h:390:5: 
  388. 
  389.     s->buffer             = buffer;
  390.     s->size_in_bits       = bit_size;
           ^
  391. #if !UNCHECKED_BITSTREAM_READER
  392.     s->size_in_bits_plus8 = bit_size + 8;

libavcodec/get_bits.h:392:5: 
  390.     s->size_in_bits       = bit_size;
  391. #if !UNCHECKED_BITSTREAM_READER
  392.     s->size_in_bits_plus8 = bit_size + 8;
           ^
  393. #endif
  394.     s->buffer_end         = buffer + buffer_size;

libavcodec/get_bits.h:394:5: 
  392.     s->size_in_bits_plus8 = bit_size + 8;
  393. #endif
  394.     s->buffer_end         = buffer + buffer_size;
           ^
  395.     s->index              = 0;
  396. 

libavcodec/get_bits.h:395:5: 
  393. #endif
  394.     s->buffer_end         = buffer + buffer_size;
  395.     s->index              = 0;
           ^
  396. 
  397.     return ret;

libavcodec/get_bits.h:397:5: 
  395.     s->index              = 0;
  396. 
  397.     return ret;
           ^
  398. }
  399. 

libavcodec/get_bits.h:398:1: return from a call to init_get_bits
  396. 
  397.     return ret;
  398. }
       ^
  399. 
  400. /**

libavcodec/vp3.c:1956:9: Taking true branch
1954.     init_get_bits(&gb, buf, buf_size * 8);
1955. 
1956.     if (s->theora && get_bits1(&gb))
              ^
1957.     {
1958.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/vp3.c:1956:22: 
1954.     init_get_bits(&gb, buf, buf_size * 8);
1955. 
1956.     if (s->theora && get_bits1(&gb))
                           ^
1957.     {
1958.         av_log(avctx, AV_LOG_ERROR, "Header packet passed to frame decoder, skipping\n");

libavcodec/get_bits.h:271:1: start of procedure get_bits1()
  269. }
  270. 
  271. static inline unsigned int get_bits1(GetBitContext *s)
       ^
  272. {
  273.     unsigned int index = s->index;

libavcodec/get_bits.h:273:5: 
  271. static inline unsigned int get_bits1(GetBitContext *s)
  272. {
  273.     unsigned int index = s->index;
           ^
  274.     uint8_t result     = s->buffer[index >> 3];
  275. #ifdef BITSTREAM_READER_LE

libavcodec/get_bits.h:274:5: 
  272. {
  273.     unsigned int index = s->index;
  274.     uint8_t result     = s->buffer[index >> 3];
           ^
  275. #ifdef BITSTREAM_READER_LE
  276.     result >>= index & 7;
