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/*! \file gsm620.c
* GSM 06.20 - GSM HR codec. */
/*
* (C) 2010 Sylvain Munaut <tnt@246tNt.com>
*
* 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.
*
*/
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <osmocom/core/bitvec.h>
#include <osmocom/core/utils.h>
#include <osmocom/codec/codec.h>
/* GSM HR unvoiced (mode=0) frames - subjective importance bit ordering */
/* This array encode mapping between GSM 05.03 Table 3a (bits
* ordering before channel coding on TCH) and GSM 06.20 Table B.1
* (bit ordering on A-bis */
const uint16_t gsm620_unvoiced_bitorder[112] = {
3, /* R0:1 */
25, /* LPC 3:7 */
52, /* GSP 0-1:2 */
71, /* GSP 0-2:2 */
90, /* GSP 0-3:2 */
109, /* GSP 0-4:2 */
15, /* LPC 1:0 */
19, /* LPC 2:5 */
20, /* LPC 2:4 */
21, /* LPC 2:3 */
22, /* LPC 2:2 */
23, /* LPC 2:1 */
26, /* LPC 3:6 */
27, /* LPC 3:5 */
28, /* LPC 3:4 */
29, /* LPC 3:3 */
30, /* LPC 3:2 */
31, /* LPC 3:1 */
61, /* Code 1-2:0 */
62, /* Code 2-2:6 */
63, /* Code 2-2:5 */
64, /* Code 2-2:4 */
65, /* Code 2-2:3 */
66, /* Code 2-2:2 */
67, /* Code 2-2:1 */
68, /* Code 2-2:0 */
74, /* Code 1-3:6 */
75, /* Code 1-3:5 */
76, /* Code 1-3:4 */
77, /* Code 1-3:3 */
78, /* Code 1-3:2 */
79, /* Code 1-3:1 */
80, /* Code 1-3:0 */
81, /* Code 2-3:6 */
82, /* Code 2-3:5 */
83, /* Code 2-3:4 */
84, /* Code 2-3:3 */
32, /* LPC 3:0 */
4, /* R0:0 */
33, /* INT-LPC:0 */
60, /* Code 1-2:1 */
59, /* Code 1-2:2 */
58, /* Code 1-2:3 */
57, /* Code 1-2:4 */
56, /* Code 1-2:5 */
55, /* Code 1-2:6 */
49, /* Code 2-1:0 */
48, /* Code 2-1:1 */
47, /* Code 2-1:2 */
46, /* Code 2-1:3 */
45, /* Code 2-1:4 */
44, /* Code 2-1:5 */
43, /* Code 2-1:6 */
42, /* Code 1-1:0 */
41, /* Code 1-1:1 */
40, /* Code 1-1:2 */
39, /* Code 1-1:3 */
38, /* Code 1-1:4 */
37, /* Code 1-1:5 */
36, /* Code 1-1:6 */
111, /* GSP 0-4:0 */
92, /* GSP 0-3:0 */
73, /* GSP 0-2:0 */
54, /* GSP 0-1:0 */
24, /* LPC 2:0 */
110, /* GSP 0-4:1 */
91, /* GSP 0-3:1 */
72, /* GSP 0-2:1 */
53, /* GSP 0-1:1 */
14, /* LPC 1:1 */
13, /* LPC 1:2 */
12, /* LPC 1:3 */
11, /* LPC 1:4 */
10, /* LPC 1:5 */
108, /* GSP 0-4:3 */
89, /* GSP 0-3:3 */
70, /* GSP 0-2:3 */
51, /* GSP 0-1:3 */
16, /* LPC 2:8 */
17, /* LPC 2:7 */
18, /* LPC 2:6 */
107, /* GSP 0-4:4 */
88, /* GSP 0-3:4 */
69, /* GSP 0-2:4 */
50, /* GSP 0-1:4 */
9, /* LPC 1:6 */
8, /* LPC 1:7 */
7, /* LPC 1:8 */
6, /* LPC 1:9 */
2, /* R0:2 */
5, /* LPC 1:10 */
1, /* R0:3 */
0, /* R0:4 */
35, /* Mode:0 */
34, /* Mode:1 */
106, /* Code 2-4:0 */
105, /* Code 2-4:1 */
104, /* Code 2-4:2 */
103, /* Code 2-4:3 */
102, /* Code 2-4:4 */
101, /* Code 2-4:5 */
100, /* Code 2-4:6 */
99, /* Code 1-4:0 */
98, /* Code 1-4:1 */
97, /* Code 1-4:2 */
96, /* Code 1-4:3 */
95, /* Code 1-4:4 */
94, /* Code 1-4:5 */
93, /* Code 1-4:6 */
87, /* Code 2-3:0 */
86, /* Code 2-3:1 */
85, /* Code 2-3:2 */
};
/* GSM HR voiced (mode=1,2,3) frames - subjective importance bit ordering */
/* This array encode mapping between GSM 05.03 Table 3b (bits
* ordering before channel coding on TCH) and GSM 06.20 Table B.2
* (bit ordering on A-bis */
const uint16_t gsm620_voiced_bitorder[112] = {
13, /* LPC 1:2 */
14, /* LPC 1:1 */
18, /* LPC 2:6 */
19, /* LPC 2:5 */
20, /* LPC 2:4 */
53, /* GSP 0-1:4 */
71, /* GSP 0-2:4 */
89, /* GSP 0-3:4 */
107, /* GSP 0-4:4 */
54, /* GSP 0-1:3 */
72, /* GSP 0-2:3 */
90, /* GSP 0-3:3 */
108, /* GSP 0-4:3 */
55, /* GSP 0-1:2 */
73, /* GSP 0-2:2 */
91, /* GSP 0-3:2 */
109, /* GSP 0-4:2 */
44, /* Code 1:8 */
45, /* Code 1:7 */
46, /* Code 1:6 */
47, /* Code 1:5 */
48, /* Code 1:4 */
49, /* Code 1:3 */
50, /* Code 1:2 */
51, /* Code 1:1 */
52, /* Code 1:0 */
62, /* Code 2:8 */
63, /* Code 2:7 */
64, /* Code 2:6 */
65, /* Code 2:5 */
68, /* Code 2:2 */
69, /* Code 2:1 */
70, /* Code 2:0 */
80, /* Code 3:8 */
66, /* Code 2:4 */
67, /* Code 2:3 */
56, /* GSP 0-1:1 */
74, /* GSP 0-2:1 */
92, /* GSP 0-3:1 */
110, /* GSP 0-4:1 */
57, /* GSP 0-1:0 */
75, /* GSP 0-2:0 */
93, /* GSP 0-3:0 */
111, /* GSP 0-4:0 */
33, /* INT-LPC:0 */
24, /* LPC 2:0 */
32, /* LPC 3:0 */
97, /* LAG 4:0 */
31, /* LPC 3:1 */
23, /* LPC 2:1 */
96, /* LAG 4:1 */
79, /* LAG 3:0 */
61, /* LAG 2:0 */
43, /* LAG 1:0 */
95, /* LAG 4:2 */
78, /* LAG 3:1 */
60, /* LAG 2:1 */
42, /* LAG 1:1 */
30, /* LPC 3:2 */
29, /* LPC 3:3 */
28, /* LPC 3:4 */
22, /* LPC 2:2 */
27, /* LPC 3:5 */
26, /* LPC 3:6 */
21, /* LPC 2:3 */
4, /* R0:0 */
25, /* LPC 3:7 */
15, /* LPC 1:0 */
94, /* LAG 4:3 */
77, /* LAG 3:2 */
59, /* LAG 2:2 */
41, /* LAG 1:2 */
3, /* R0:1 */
76, /* LAG 3:3 */
58, /* LAG 2:3 */
40, /* LAG 1:3 */
39, /* LAG 1:4 */
17, /* LPC 2:7 */
16, /* LPC 2:8 */
12, /* LPC 1:3 */
11, /* LPC 1:4 */
10, /* LPC 1:5 */
9, /* LPC 1:6 */
2, /* R0:2 */
38, /* LAG 1:5 */
37, /* LAG 1:6 */
36, /* LAG 1:7 */
8, /* LPC 1:7 */
7, /* LPC 1:8 */
6, /* LPC 1:9 */
5, /* LPC 1:10 */
1, /* R0:3 */
0, /* R0:4 */
35, /* Mode:0 */
34, /* Mode:1 */
106, /* Code 4:0 */
105, /* Code 4:1 */
104, /* Code 4:2 */
103, /* Code 4:3 */
102, /* Code 4:4 */
101, /* Code 4:5 */
100, /* Code 4:6 */
99, /* Code 4:7 */
98, /* Code 4:8 */
88, /* Code 3:0 */
87, /* Code 3:1 */
86, /* Code 3:2 */
85, /* Code 3:3 */
84, /* Code 3:4 */
83, /* Code 3:5 */
82, /* Code 3:6 */
81, /* Code 3:7 */
};
/*! Check whether RTP frame contains HR SID code word according to
* TS 101 318 §5.2.2
* \param[in] rtp_payload Buffer with RTP payload
* \param[in] payload_len Length of payload
* \returns true if code word is found, false otherwise
*/
bool osmo_hr_check_sid(const uint8_t *rtp_payload, size_t payload_len)
{
struct bitvec bv = {
.data = (uint8_t *)rtp_payload,
.data_len = payload_len,
};
/* A SID frame is identified by a SID codeword consisting of 79 bits which are all 1,
* so we basically check if all bits in range r34..r112 (inclusive) are 1. */
for (bv.cur_bit = 33; bv.cur_bit < bv.data_len * 8; bv.cur_bit++)
if (bitvec_get_bit_pos(&bv, bv.cur_bit) != ONE)
return false;
return true;
}
/*! Reset the SID field of a potentially corrupted, but still valid GSM-HR
* SID frame in TS 101 318 format to its pristine state (full SID codeword).
* \param[in] rtp_payload Buffer with RTP payload - must be writable!
*
* Per GSM 06.22 section 5.3, a freshly minted SID frame consists of 33 bits
* of comfort noise parameters and 79 bits of SID codeword (all 1s). Network
* elements that receive SID frames from call leg A uplink and need to
* retransmit them on leg B downlink should "rejuvenate" received SID frames
* prior to retransmission by resetting the SID field to its pristine state
* of all 1s; this function does the job.
*
* Important note: because of HR-specific quirks (lack of exact bit counting
* rules in GSM 06.41 spec compared to 06.31 & 06.81, plus the fact that such
* bit counting can only be done efficiently in the GSM 05.03 channel decoder
* prior to bit reordering based on voiced or unvoiced mode), a generic
* (usable from any network element) SID classification function similar to
* osmo_{fr,efr}_sid_classify() unfortunately cannot exist for HR. Therefore,
* the triggering condition for invoking this SID rejuvenation/reset function
* can only be an out-of-band SID indication, as in GSM 08.61 TRAU frames
* or RFC 5993 ToC octet.
*/
void osmo_hr_sid_reset(uint8_t *rtp_payload)
{
/* set all 79 SID codeword bits to 1 */
rtp_payload[4] |= 0x7F;
memset(rtp_payload + 5, 0xFF, 9);
}
|
