static void start_frame_overlay(AVFilterLink *inlink, AVFilterBufferRef *inpicref) { AVFilterContext *ctx = inlink->dst; OverlayContext *over = ctx->priv; inpicref->pts = av_rescale_q(inpicref->pts, ctx->inputs[OVERLAY]->time_base, ctx->outputs[0]->time_base); if (!over->overpicref) over->overpicref = inpicref; else over->overpicref_next = inpicref; }