fixed 2 possible heap overflows (inc. #1088)
GF_Err dmed_Write(GF_Box *s, GF_BitStream *bs)
{
	GF_Err e;
	GF_DMEDBox *ptr = (GF_DMEDBox *)s;
	if (ptr == NULL) return GF_BAD_PARAM;
	e = gf_isom_box_write_header(s, bs);
	if (e) return e;
	gf_bs_write_u64(bs, ptr->nbBytes);
	return GF_OK;
}

GF_Err dmed_Write(GF_Box *s, GF_BitStream *bs)
{
	GF_Err e;
	GF_DMEDBox *ptr = (GF_DMEDBox *)s;
	if (ptr == NULL) return GF_BAD_PARAM;
	e = gf_isom_box_write_header(s, bs);
	if (e) return e;
	gf_bs_write_u64(bs, ptr->nbBytes);
	return GF_OK;
}
