start_line = bytestream2_get_be16(&s->g);
bytestream2_skip(&s->g, 2);
height = bytestream2_get_be16(&s->g);
bytestream2_skip(&s->g, 2);
if (height > s->avctx->height - start_line)
start_line = bytestream2_get_be16(&s->g);
bytestream2_skip(&s->g, 2);
height = bytestream2_get_be16(&s->g);
bytestream2_skip(&s->g, 2);
if (height > s->avctx->height - start_line)