annotate libgsmefr/dec_lag6.c @ 176:9fb22fa4d373

doc/RTP-analysis: document rtp-g711-extr
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 27 Dec 2022 01:29:14 +0000
parents cb080ec1817e
children f387ee919f2c
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 /*************************************************************************
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 * FUNCTION: Dec_lag6
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 *
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 * PURPOSE: Decoding of fractional pitch lag with 1/6 resolution.
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 * Extract the integer and fraction parts of the pitch lag from
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 * the received adaptive codebook index.
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 *
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 * See "Enc_lag6.c" for more details about the encoding procedure.
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 *
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 * The fractional lag in 1st and 3rd subframes is encoded with 9 bits
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 * while that in 2nd and 4th subframes is relatively encoded with 6 bits.
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 * Note that in relative encoding only 61 values are used. If the
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 * decoder receives 61, 62, or 63 as the relative pitch index, it means
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 * that a transmission error occurred. In this case, the pitch lag from
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 * previous subframe is used.
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 *
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 *************************************************************************/
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
19 #include "gsm_efr.h"
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 #include "typedef.h"
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
21 #include "namespace.h"
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22 #include "basic_op.h"
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
23 #include "no_count.h"
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
24 #include "codec.h"
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
25 #include "cnst.h"
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
26 #include "dec_state.h"
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
28 Word16 Dec_lag6 ( /* output: return integer pitch lag */
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
29 struct EFR_decoder_state *st,
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 Word16 index, /* input : received pitch index */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 Word16 pit_min, /* input : minimum pitch lag */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 Word16 pit_max, /* input : maximum pitch lag */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33 Word16 i_subfr, /* input : subframe flag */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 Word16 L_frame_by2,/* input : speech frame size divided by 2 */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 Word16 *T0_frac, /* output: fractional part of pitch lag */
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
36 Word16 bfi, /* input : bad frame indicator */
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
37 Word16 *T0_min,
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
38 Word16 *T0_max
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 )
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 Word16 pit_flag;
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 Word16 T0, i;
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 pit_flag = i_subfr; move16 (); /* flag for 1st or 3rd subframe */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 test ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 if (sub (i_subfr, L_frame_by2) == 0)
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 pit_flag = 0; move16 ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50 test ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
51 if (pit_flag == 0) /* if 1st or 3rd subframe */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
52 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
53 test ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
54 if (bfi == 0)
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
55 { /* if bfi == 0 decode pitch */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
56 test ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
57 if (sub (index, 463) < 0)
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
58 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
59 /* T0 = (index+5)/6 + 17 */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
60 T0 = add (mult (add (index, 5), 5462), 17);
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
61 i = add (add (T0, T0), T0);
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
62 /* *T0_frac = index - T0*6 + 105 */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
63 *T0_frac = add (sub (index, add (i, i)), 105);
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
64 move16 ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
65 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
66 else
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
67 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
68 T0 = sub (index, 368);
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
69 *T0_frac = 0; move16 ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
70 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
71 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
72 else
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
73 /* bfi == 1 */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
74 {
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
75 T0 = st->old_T0;
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
76 *T0_frac = 0;
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
77 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
78
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
79 /* find T0_min and T0_max for 2nd (or 4th) subframe */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
80
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
81 *T0_min = sub (T0, 5);
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
82 if (sub (*T0_min, pit_min) < 0)
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
83 {
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
84 *T0_min = pit_min;
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
85 }
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
86 *T0_max = add (*T0_min, 9);
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
87 if (sub (*T0_max, pit_max) > 0)
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
88 {
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
89 *T0_max = pit_max;
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
90 *T0_min = sub (*T0_max, 9);
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
91 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
92 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
93 else
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
94 /* second or fourth subframe */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
95 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
96 test (); test ();
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
97 /* if bfi == 0 decode pitch */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
98 if ((bfi == 0) && (sub (index, 61) < 0))
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
99 {
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
100 /* i = (index+5)/6 - 1 */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
101 i = sub (mult (add (index, 5), 5462), 1);
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
102 T0 = add (i, *T0_min);
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
103 i = add (add (i, i), i);
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
104 *T0_frac = sub (sub (index, 3), add (i, i));
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
105 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
106 else
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
107 /* bfi == 1 OR index >= 61 */
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
108 {
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
109 T0 = st->old_T0;
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
110 *T0_frac = 0;
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
111 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
112 }
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
113
65
cb080ec1817e libgsmefr: dec_lag6.c compiles
Mychaela Falconia <falcon@freecalypso.org>
parents: 53
diff changeset
114 st->old_T0 = T0;
53
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
115
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
116 return T0;
49dd1ac8e75b libgsmefr: import most *.c files from ETSI source
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
117 }