static s32 bs_get_se(GF_BitStream *bs)
{
	u32 v = bs_get_ue(bs);
	if ((v & 0x1) == 0) return (s32) (0 - (v>>1));
	return (v + 1) >> 1;
}
static s32 bs_get_se(GF_BitStream *bs)
{
	u32 v = bs_get_ue(bs);
	if ((v & 0x1) == 0) return (s32) (0 - (v>>1));
	return (v + 1) >> 1;
}