| /* |
| * (C) 2020 by sysmocom - s.f.m.c. GmbH, Author: Philipp Maier |
| * All Rights Reserved |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| * |
| */ |
| |
| #include <stdio.h> |
| #include <stdint.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <errno.h> |
| |
| #include <osmocom/core/bits.h> |
| #include <osmocom/core/conv.h> |
| #include <osmocom/core/utils.h> |
| #include <osmocom/coding/gsm0503_amr_dtx.h> |
| #include <osmocom/coding/gsm0503_parity.h> |
| #include <osmocom/gsm/gsm0503.h> |
| |
| /* See also: 3GPP TS 05.03, chapter 3.10.1.3, 3.10.5.2 Identification marker */ |
| static const ubit_t id_marker_1[] = { 1, 0, 1, 1, 0, 0, 0, 0, 1 }; |
| |
| /* See also: 3GPP TS 05.03, chapter 3.9.1.3, 3.10.2.2, 3.10.2.2 Identification marker */ |
| static const ubit_t id_marker_0[] = { 0, 1, 0, 0, 1, 1, 1, 1, 0 }; |
| |
| /* See also: 3GPP TS 05.03, chapter 3.9 Adaptive multi rate speech channel at full rate (TCH/AFS) */ |
| static const ubit_t codec_mode_1_sid[] = { 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0 }; |
| static const ubit_t codec_mode_2_sid[] = { 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0 }; |
| static const ubit_t codec_mode_3_sid[] = { 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1 }; |
| static const ubit_t codec_mode_4_sid[] = { 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1 }; |
| |
| const struct value_string gsm0503_amr_dtx_frame_names[] = { |
| { AMR_OTHER, "AMR_OTHER (audio)" }, |
| { AFS_SID_FIRST, "AFS_SID_FIRST" }, |
| { AFS_SID_UPDATE, "AFS_SID_UPDATE (marker)" }, |
| { AFS_SID_UPDATE_CN, "AFS_SID_UPDATE_CN (audio)" }, |
| { AFS_ONSET, "AFS_ONSET" }, |
| { AHS_SID_UPDATE, "AHS_SID_UPDATE (marker)" }, |
| { AHS_SID_UPDATE_CN, "AHS_SID_UPDATE_CN (audio)" }, |
| { AHS_SID_FIRST_P1, "AHS_SID_FIRST_P1" }, |
| { AHS_SID_FIRST_P2, "AHS_SID_FIRST_P2" }, |
| { AHS_ONSET, "AHS_ONSET" }, |
| { AHS_SID_FIRST_INH, "AHS_SID_FIRST_INH" }, |
| { AHS_SID_UPDATE_INH, "AHS_SID_UPDATE_INH" }, |
| { 0, NULL } |
| }; |
| |
| static bool detect_afs_id_marker(int *n_errors, int *n_bits_total, const ubit_t * ubits, uint8_t offset, uint8_t count, |
| const ubit_t * id_marker, uint8_t id_marker_len) |
| { |
| unsigned int i, k; |
| unsigned int id_bit_nr = 0; |
| int errors = 0; |
| int bits = 0; |
| |
| /* Override coded in-band data */ |
| ubits += offset; |
| |
| /* Check for identification marker bits */ |
| for (i = 0; i < count; i++) { |
| for (k = 0; k < 4; k++) { |
| if (id_marker[id_bit_nr % id_marker_len] != *ubits) |
| errors++; |
| id_bit_nr++; |
| ubits++; |
| bits++; |
| } |
| |
| /* Jump to the next block of 4 bits */ |
| ubits += 4; |
| } |
| |
| *n_errors = errors; |
| *n_bits_total = bits; |
| |
| /* Tolerate up to 1/8 errornous bits */ |
| return *n_errors < *n_bits_total / 8; |
| } |
| |
| static bool detect_ahs_id_marker(int *n_errors, int *n_bits_total, const ubit_t * ubits, const ubit_t * id_marker) |
| { |
| unsigned int i, k; |
| int errors = 0; |
| int bits = 0; |
| |
| /* Override coded in-band data */ |
| ubits += 16; |
| |
| /* Check first identification marker bits (23*9 bits) */ |
| for (i = 0; i < 23; i++) { |
| for (k = 0; k < 9; k++) { |
| if (id_marker[k] != *ubits) |
| errors++; |
| ubits++; |
| bits++; |
| } |
| } |
| |
| /* Check remaining identification marker bits (5 bits) */ |
| for (k = 0; k < 5; k++) { |
| if (id_marker[k] != *ubits) |
| errors++; |
| ubits++; |
| bits++; |
| } |
| |
| *n_errors = errors; |
| *n_bits_total = bits; |
| |
| /* Tolerate up to 1/8 errornous bits */ |
| return *n_errors < *n_bits_total / 8; |
| } |
| |
| static bool detect_interleaved_ahs_id_marker(int *n_errors, int *n_bits_total, const ubit_t * ubits, uint8_t offset, |
| uint8_t n_bits, const ubit_t * id_marker, uint8_t id_marker_len) |
| { |
| unsigned int i, k; |
| int errors = 0; |
| int bits = 0; |
| uint8_t full_rounds = n_bits / id_marker_len; |
| uint8_t remainder = n_bits % id_marker_len; |
| |
| /* Override coded in-band data */ |
| ubits += offset; |
| |
| /* Check first identification marker bits (23*9 bits) */ |
| for (i = 0; i < full_rounds; i++) { |
| for (k = 0; k < id_marker_len; k++) { |
| if (id_marker[k] != *ubits) |
| errors++; |
| ubits += 2; |
| bits++; |
| } |
| } |
| |
| /* Check remaining identification marker bits (5 bits) */ |
| for (k = 0; k < remainder; k++) { |
| if (id_marker[k] != *ubits) |
| errors++; |
| ubits += 2; |
| bits++; |
| } |
| |
| *n_errors = errors; |
| *n_bits_total = bits; |
| |
| /* Tolerate up to 1/8 errornous bits */ |
| return *n_errors < *n_bits_total / 8; |
| } |
| |
| /* Detect a an FR AMR SID_FIRST frame by its identifcation marker */ |
| static bool detect_afs_sid_first(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| return detect_afs_id_marker(n_errors, n_bits_total, ubits, 32, 53, id_marker_0, 9); |
| } |
| |
| /* Detect an FR AMR SID_FIRST frame by its identification marker */ |
| static bool detect_afs_sid_update(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| return detect_afs_id_marker(n_errors, n_bits_total, ubits, 36, 53, id_marker_0, 9); |
| } |
| |
| /* Detect an FR AMR SID_FIRST frame by its repeating coded inband data */ |
| static bool detect_afs_onset(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| bool rc; |
| |
| rc = detect_afs_id_marker(n_errors, n_bits_total, ubits, 4, 57, codec_mode_1_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_afs_id_marker(n_errors, n_bits_total, ubits, 4, 57, codec_mode_2_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_afs_id_marker(n_errors, n_bits_total, ubits, 4, 57, codec_mode_3_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_afs_id_marker(n_errors, n_bits_total, ubits, 4, 57, codec_mode_4_sid, 16); |
| if (rc) |
| return true; |
| |
| return false; |
| } |
| |
| /* Detect an HR AMR SID UPDATE frame by its identification marker */ |
| static bool detect_ahs_sid_update(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| return detect_ahs_id_marker(n_errors, n_bits_total, ubits, id_marker_1); |
| } |
| |
| /* Detect an HR AMR SID FIRST (part 1) frame by its identification marker */ |
| static bool detect_ahs_sid_first_p1(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| return detect_ahs_id_marker(n_errors, n_bits_total, ubits, id_marker_0); |
| } |
| |
| /* Detect an HR AMR SID FIRST (part 2) frame by its repeating coded inband data */ |
| static bool detect_ahs_sid_first_p2(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| bool rc; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 0, 114, codec_mode_1_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 0, 114, codec_mode_2_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 0, 114, codec_mode_3_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 0, 114, codec_mode_4_sid, 16); |
| if (rc) |
| return true; |
| |
| return false; |
| } |
| |
| /* Detect an HR AMR ONSET frame by its repeating coded inband data */ |
| static bool detect_ahs_onset(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| bool rc; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 1, 114, codec_mode_1_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 1, 114, codec_mode_2_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 1, 114, codec_mode_3_sid, 16); |
| if (rc) |
| return true; |
| |
| rc = detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 1, 114, codec_mode_4_sid, 16); |
| if (rc) |
| return true; |
| |
| return false; |
| } |
| |
| /* Detect an HR AMR SID FIRST INHIBIT frame by its identification marker */ |
| static bool detect_ahs_sid_first_inh(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| return detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 33, 212, id_marker_1, 9); |
| } |
| |
| /* Detect an HR AMR SID UPDATE INHIBIT frame by its identification marker */ |
| static bool detect_ahs_sid_update_inh(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| return detect_interleaved_ahs_id_marker(n_errors, n_bits_total, ubits, 33, 212, id_marker_0, 9); |
| } |
| |
| /*! Detect FR AMR DTX frame in unmapped, deinterleaved frame bits. |
| * \param[in] ubits input bits (456 bit). |
| * \param[out] n_errors number of errornous bits. |
| * \param[out] n_bits_total number of checked bits. |
| * \returns dtx frame type. */ |
| enum gsm0503_amr_dtx_frames gsm0503_detect_afs_dtx_frame(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| if (detect_afs_sid_first(n_errors, n_bits_total, ubits)) |
| return AFS_SID_FIRST; |
| if (detect_afs_sid_update(n_errors, n_bits_total, ubits)) |
| return AFS_SID_UPDATE; |
| if (detect_afs_onset(n_errors, n_bits_total, ubits)) |
| return AFS_ONSET; |
| |
| *n_errors = 0; |
| *n_bits_total = 0; |
| return AMR_OTHER; |
| } |
| |
| /*! Detect HR AMR DTX frame in unmapped, deinterleaved frame bits. |
| * \param[in] ubits input bits (456 bit). |
| * \param[out] n_errors number of errornous bits. |
| * \param[out] n_bits_total number of checked bits. |
| * \returns dtx frame type, */ |
| enum gsm0503_amr_dtx_frames gsm0503_detect_ahs_dtx_frame(int *n_errors, int *n_bits_total, const ubit_t * ubits) |
| { |
| if (detect_ahs_sid_update(n_errors, n_bits_total, ubits)) |
| return AHS_SID_UPDATE; |
| if (detect_ahs_sid_first_inh(n_errors, n_bits_total, ubits)) |
| return AHS_SID_FIRST_INH; |
| if (detect_ahs_sid_update_inh(n_errors, n_bits_total, ubits)) |
| return AHS_SID_UPDATE_INH; |
| if (detect_ahs_sid_first_p1(n_errors, n_bits_total, ubits)) |
| return AHS_SID_FIRST_P1; |
| if (detect_ahs_sid_first_p2(n_errors, n_bits_total, ubits)) |
| return AHS_SID_FIRST_P2; |
| if (detect_ahs_onset(n_errors, n_bits_total, ubits)) |
| return AHS_ONSET; |
| |
| *n_errors = 0; |
| *n_bits_total = 0; |
| return AMR_OTHER; |
| } |