Function bound_reorder 

pub fn bound_reorder(
    nal: &[u8],
    in_order: bool,
) -> Result<Option<Vec<u8>>, String>

The same SPS bounding reordering at zero, or None where it already does: a restriction written where the VUI carries none (a VUI created where there is none), with every other restriction field at the value a decoder infers in its absence and max_dec_frame_buffering at max_num_ref_frames; a declared max_num_reorder_frames above zero rewritten to zero. Only a stream that cannot reorder takes it: in_order where the session proves its pictures leave in the order they are shown, else a stream at picture order count type 2, whose output order is its decoding order.