/* default config_link() implementation for output video links to simplify the implementation of one input one output video filters  */
int avfilter_default_config_output_link(AVFilterLink *link)
/* default config_link() implementation for output video links to simplify the implementation of one input one output video filters  */
int avfilter_default_config_output_link(AVFilterLink *link)
{
    if(link->src->input_count && link->src->inputs[0]) {
        link->w = link->src->inputs[0]->w;
        link->h = link->src->inputs[0]->h;
    } else {
        return -1;
    }
    return 0;
}