scale->flags, NULL, NULL, NULL);
if (scale->isws[0])
sws_freeContext(scale->isws[0]);
scale->isws[0] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,
scale->flags, NULL, NULL, NULL);
if (scale->isws[0])
sws_freeContext(scale->isws[0]);
scale->isws[0] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,