bs_write_se
bs_write_se(s, qp - 26); /* pic_init_qp_minus26 */
bs_write_se(s, qp - 26); /* pic_init_qs_minus26 */
bs_write_se(s, 0); /* chroma_qp_index_offset */
bs_write_se(s, 0); /* slice_qp_delta */