FreeCalypso > hg > ice1-trau-tester

comparison ater8/out_frame.c @ 42:ff94d7fc5891

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new program itt-ater-8
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 30 Aug 2024 19:02:42 +0000
parents ater/out_frame.c@bacc590ec839
children
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41:50a72d4ff498 42:ff94d7fc5891
1 /*
2 * Here we implement our TRAU-UL bit filling function for HRv1 8 kbit/s format.
3 *
4 * This code is based (very loosely) on trau_rtp_conv.c in libosmo-abis.
5 */
6
7 #include <stdint.h>
8 #include <stdbool.h>
9 #include <string.h>
10
11 #include <osmocom/core/bits.h>
12 #include <osmocom/core/crc8gen.h>
13 #include <osmocom/core/utils.h>
14 #include <osmocom/trau/trau_frame.h>
15 #include "../libhr/tw_gsmhr.h"
16
17 #include "out_frame.h"
18
19 /*
20 * EFR TRAU parity (also used for HR)
21 *
22 * g(x) = x^3 + x^1 + 1
23 */
24 static const struct osmo_crc8gen_code gsm0860_efr_crc3 = {
25 .bits = 3,
26 .poly = 0x3,
27 .init = 0x0,
28 .remainder = 0x7,
29 };
30
31 void trau_frame_from_record(const int16_t *rec, struct osmo_trau_frame *tf,
32 bool *has_taf)
33 {
34 uint8_t ts101318[GSMHR_FRAME_LEN_RPF];
35 int16_t bfi, sid;
36
37 /* payload transformation is straightforward */
38 gsmhr_pack_ts101318(rec, ts101318);
39 osmo_pbit2ubit(tf->d_bits, ts101318, 14 * 8);
40 osmo_crc8gen_set_bits(&gsm0860_efr_crc3, tf->d_bits, 44, tf->crc_bits);
41
42 /* transformation of metadata flags is the messy part */
43 bfi = rec[18];
44 sid = rec[20];
45 switch (sid) {
46 case 0:
47 if (bfi) {
48 tf->xc_bits[1] = 1;
49 tf->xc_bits[2] = 1;
50 *has_taf = true;
51 } else {
52 tf->xc_bits[1] = 0;
53 tf->xc_bits[2] = 0;
54 tf->xc_bits[3] = 0;
55 *has_taf = false;
56 }
57 break;
58 case 1:
59 tf->xc_bits[1] = 1;
60 tf->xc_bits[2] = 0;
61 *has_taf = true;
62 break;
63 case 2:
64 if (bfi) {
65 tf->xc_bits[1] = 1;
66 tf->xc_bits[2] = 0;
67 *has_taf = true;
68 } else {
69 tf->xc_bits[1] = 0;
70 tf->xc_bits[2] = 0;
71 tf->xc_bits[3] = 1;
72 *has_taf = false;
73 }
74 break;
75 default:
76 OSMO_ASSERT(0);
77 }
78 /* XC5 is always UFI */
79 tf->xc_bits[4] = rec[19];
80 }