func: static int parse(AVCodecParserContext *ctx,
  
                   AVCodecContext *avctx,
  
                   const uint8_t **out_data, int *out_size,
  
                   const uint8_t *data, int size)
  
  {
  
      VP9ParseContext *s = ctx->priv_data;
  
      int marker;
  
  
  
      if (size <= 0) {
  
          *out_size = 0;
  
          *out_data = data;
  
  
  
          return 0;
  
      }
  
  
  
      if (s->n_frames > 0) {
  
          *out_data = data;
  
          *out_size = s->size[--s->n_frames];
  
          parse_frame(ctx, *out_data, *out_size);
  
  
  
          return s->n_frames > 0 ? *out_size : size /* i.e. include idx tail */;
  
      }
  
  
  
      marker = data[size - 1];
  
      if ((marker & 0xe0) == 0xc0) {
  
          int nbytes = 1 + ((marker >> 3) & 0x3);
  
          int n_frames = 1 + (marker & 0x7), idx_sz = 2 + n_frames * nbytes;
  
  
  
          if (size >= idx_sz && data[size - idx_sz] == marker) {
  
              const uint8_t *idx = data + size + 1 - idx_sz;
  
              int first = 1;
  
  
  
              switch (nbytes) {
  
  #define case_n(a, rd) \
  
              case a: \
  
                  while (n_frames--) { \
  
                      int sz = rd; \
  
                      idx += a; \
  
                      if (sz > size) { \
  
                          s->n_frames = 0; \
  
                          av_log(avctx, AV_LOG_ERROR, \
  
                                 "Superframe packet size too big: %d > %d\n", \
  
                                 sz, size); \
  
                          return AVERROR_INVALIDDATA; \
  
                      } \
  
                      if (first) { \
  
                          first = 0; \
  
                          *out_data = data; \
  
                          *out_size = sz; \
  
                          s->n_frames = n_frames; \
  
                      } else { \
  
                          s->size[n_frames] = sz; \
  
                      } \
  
                      data += sz; \
  
                      size -= sz; \
  
                  } \
  
                  parse_frame(ctx, *out_data, *out_size); \
  
                  return *out_size
  
  
  
                  case_n(1, *idx);
  
                  case_n(2, AV_RL16(idx));
  
                  case_n(3, AV_RL24(idx));
  
                  case_n(4, AV_RL32(idx));
  
              }
  
          }
  
      }
  
  
  
      *out_data = data;
  
      *out_size = size;
  
      parse_frame(ctx, data, size);
  
  
  
      return size;
  
  }
  