StackContext *s = ctx->priv;
AVRational time_base = ctx->inputs[0]->time_base;
AVRational frame_rate = ctx->inputs[0]->frame_rate;
StackContext *s = ctx->priv;
AVRational time_base = ctx->inputs[0]->time_base;
AVRational frame_rate = ctx->inputs[0]->frame_rate;