func: int av_vsrc_buffer_add_video_buffer_ref(AVFilterContext *buffer_filter, AVFilterBufferRef *picref)
  
  {
  
      BufferSourceContext *c = buffer_filter->priv;
  
      AVFilterLink *outlink = buffer_filter->outputs[0];
  
      int ret;
  
  
  
      if (c->picref) {
  
          av_log(buffer_filter, AV_LOG_ERROR,
  
                 "Buffering several frames is not supported. "
  
                 "Please consume all available frames before adding a new one.\n"
  
              );
  
          //return -1;
  
      }
  
  
  
      if (picref->video->w != c->w || picref->video->h != c->h || picref->format != c->pix_fmt) {
  
          AVFilterContext *scale = buffer_filter->outputs[0]->dst;
  
          AVFilterLink *link;
  
          char scale_param[1024];
  
  
  
          av_log(buffer_filter, AV_LOG_INFO,
  
                 "Buffer video input changed from size:%dx%d fmt:%s to size:%dx%d fmt:%s\n",
  
                 c->w, c->h, av_pix_fmt_descriptors[c->pix_fmt].name,
  
                 picref->video->w, picref->video->h, av_pix_fmt_descriptors[picref->format].name);
  
  
  
          if (!scale || strcmp(scale->filter->name, "scale")) {
  
              AVFilter *f = avfilter_get_by_name("scale");
  
  
  
              av_log(buffer_filter, AV_LOG_INFO, "Inserting scaler filter\n");
  
              if ((ret = avfilter_open(&scale, f, "Input equalizer")) < 0)
  
                  return ret;
  
  
  
              snprintf(scale_param, sizeof(scale_param)-1, "%d:%d:%s", c->w, c->h, c->sws_param);
  
              if ((ret = avfilter_init_filter(scale, scale_param, NULL)) < 0) {
  
                  avfilter_free(scale);
  
                  return ret;
  
              }
  
  
  
              if ((ret = avfilter_insert_filter(buffer_filter->outputs[0], scale, 0, 0)) < 0) {
  
                  avfilter_free(scale);
  
                  return ret;
  
              }
  
              scale->outputs[0]->time_base = scale->inputs[0]->time_base;
  
  
  
              scale->outputs[0]->format= c->pix_fmt;
  
          } else if (!strcmp(scale->filter->name, "scale")) {
  
              snprintf(scale_param, sizeof(scale_param)-1, "%d:%d:%s",
  
                       scale->outputs[0]->w, scale->outputs[0]->h, c->sws_param);
  
              scale->filter->init(scale, scale_param, NULL);
  
          }
  
  
  
          c->pix_fmt = scale->inputs[0]->format = picref->format;
  
          c->w       = scale->inputs[0]->w      = picref->video->w;
  
          c->h       = scale->inputs[0]->h      = picref->video->h;
  
  
  
          link = scale->outputs[0];
  
          if ((ret =  link->srcpad->config_props(link)) < 0)
  
              return ret;
  
      }
  
  
  
      c->picref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE,
  
                                            picref->video->w, picref->video->h);
  
      av_image_copy(c->picref->data, c->picref->linesize,
  
                    picref->data, picref->linesize,
  
                    picref->format, picref->video->w, picref->video->h);
  
      avfilter_copy_buffer_ref_props(c->picref, picref);
  
  
  
      return 0;
  
  }
  