func: AVBitStreamFilterContext *av_bitstream_filter_init(const char *name)
  
  {
  
      AVBitStreamFilter *bsf = first_bitstream_filter;
  
  
  
      while (bsf) {
  
          if (!strcmp(name, bsf->name)) {
  
              AVBitStreamFilterContext *bsfc =
  
                  av_mallocz(sizeof(AVBitStreamFilterContext));
  
              bsfc->filter    = bsf;
  
              bsfc->priv_data =
  
                  bsf->priv_data_size ? av_mallocz(bsf->priv_data_size) : NULL;
  
              return bsfc;
  
          }
  
          bsf = bsf->next;
  
      }
  
      return NULL;
  
  }
  