int avfilter_link(AVFilterContext *src, unsigned srcpad, AVFilterContext *dst, unsigned dstpad) { AVFilterLink *link; if (src->nb_outputs <= srcpad || dst->nb_inputs <= dstpad || src->outputs[srcpad] || dst->inputs[dstpad]) return -1; if (src->output_pads[srcpad].type != dst->input_pads[dstpad].type) { av_log(src, AV_LOG_ERROR, "Media type mismatch between the '%s' filter output pad %d and the '%s' filter input pad %d\n", src->name, srcpad, dst->name, dstpad); return AVERROR(EINVAL); } src->outputs[srcpad] = dst-> inputs[dstpad] = link = av_mallocz(sizeof(AVFilterLink)); link->src = src; link->dst = dst; link->srcpad = &src->output_pads[srcpad]; link->dstpad = &dst->input_pads[dstpad]; link->type = src->output_pads[srcpad].type; assert(AV_PIX_FMT_NONE == -1 && AV_SAMPLE_FMT_NONE == -1); link->format = -1; return 0; }