1 /*
2
3 * Revision 1.2 1996/08/20 20:30:11 jaf
4 * Removed all static local variables that were SAVE'd in the Fortran
5 * code, and put them in struct lpc10_encoder_state that is passed as an
6 * argument.
7 *
8 * Removed init function, since all initialization is now done in
9 * init_lpc10_encoder_state().
10 *
11 * Changed name of function from lpcenc_ to lpc10_encode, simply to make
12 * all lpc10 functions have more consistent naming with each other.
13 *
14 * Revision 1.1 1996/08/19 22:31:48 jaf
15 * Initial revision
16 *
17
18 */
19
20 /* -- translated by f2c (version 19951025).
21 You must link the resulting object file with the libraries:
22 -lf2c -lm (in that order)
23 */
24
25 #include "f2c.h"
26
27 extern int lpcdec_(integer *bits, real *speech);
28 extern int initlpcdec_(void);
29
30 /* Common Block Declarations */
31
32 extern struct {
33 integer order, lframe;
34 logical corrp;
35 } contrl_;
36
37 #define contrl_1 contrl_
38
39 /* Table of constant values */
40
41 static integer c__10 = 10;
42
43 /* ***************************************************************** */
44
45 /*
46 * Revision 1.2 1996/08/20 20:30:11 jaf
47 * Removed all static local variables that were SAVE'd in the Fortran
48 * code, and put them in struct lpc10_encoder_state that is passed as an
49 * argument.
50 *
51 * Removed init function, since all initialization is now done in
52 * init_lpc10_encoder_state().
53 *
54 * Changed name of function from lpcenc_ to lpc10_encode, simply to make
55 * all lpc10 functions have more consistent naming with each other.
56 *
57 * Revision 1.1 1996/08/19 22:31:48 jaf
58 * Initial revision
59 * */
60 /* Revision 1.1 1996/03/28 00:03:00 jaf */
61 /* Initial revision */
62
63
64 /* ***************************************************************** */
65
66 /* Decode 54 bits to one frame of 180 speech samples. */
67
68 /* Input: */
69 /* BITS - 54 encoded bits, stored 1 per array element. */
70 /* Indices 1 through 53 read (SYNC bit ignored). */
71 /* Output: */
72 /* SPEECH - Speech encoded as real values in the range [-1,+1]. */
73 /* Indices 1 through 180 written. */
74
75 /* This subroutine maintains local state from one call to the next. If */
76 /* you want to switch to using a new audio stream for this filter, or */
77 /* reinitialize its state for any other reason, call the ENTRY */
78 /* INITLPCDEC. */
79
lpc10_decode(integer * bits,real * speech,struct lpc10_decoder_state * st)80 /* Subroutine */ int lpc10_decode(integer *bits, real *speech,
81 struct lpc10_decoder_state *st)
82 {
83 integer irms, voice[2], pitch, ipitv;
84 extern /* Subroutine */ int decode_(integer *, integer *, integer *,
85 integer *, integer *, real *, real *, struct lpc10_decoder_state *);
86 real rc[10];
87 extern /* Subroutine */ int chanrd_(integer *, integer *, integer *,
88 integer *, integer *), synths_(integer *,
89 integer *, real *, real *, real *, integer *,
90 struct lpc10_decoder_state *);
91 integer irc[10], len;
92 real rms;
93
94
95 /* LPC Configuration parameters: */
96 /* Frame size, Prediction order, Pitch period */
97 /* Arguments */
98 /* LPC Processing control variables: */
99
100 /* *** Read-only: initialized in setup */
101
102 /* Files for Speech, Parameter, and Bitstream Input & Output, */
103 /* and message and debug outputs. */
104
105 /* Here are the only files which use these variables: */
106
107 /* lpcsim.f setup.f trans.f error.f vqsetup.f */
108
109 /* Many files which use fdebug are not listed, since it is only used in */
110 /* those other files conditionally, to print trace statements. */
111 /* integer fsi, fso, fpi, fpo, fbi, fbo, pbin, fmsg, fdebug */
112 /* LPC order, Frame size, Quantization rate, Bits per frame, */
113 /* Error correction */
114 /* Subroutine SETUP is the only place where order is assigned a value, */
115 /* and that value is 10. It could increase efficiency 1% or so to */
116 /* declare order as a constant (i.e., a Fortran PARAMETER) instead of as
117 */
118 /* a variable in a COMMON block, since it is used in many places in the */
119 /* core of the coding and decoding routines. Actually, I take that back.
120 */
121 /* At least when compiling with f2c, the upper bound of DO loops is */
122 /* stored in a local variable before the DO loop begins, and then that is
123 */
124 /* compared against on each iteration. */
125 /* Similarly for lframe, which is given a value of MAXFRM in SETUP. */
126 /* Similarly for quant, which is given a value of 2400 in SETUP. quant */
127 /* is used in only a few places, and never in the core coding and */
128 /* decoding routines, so it could be eliminated entirely. */
129 /* nbits is similar to quant, and is given a value of 54 in SETUP. */
130 /* corrp is given a value of .TRUE. in SETUP, and is only used in the */
131 /* subroutines ENCODE and DECODE. It doesn't affect the speed of the */
132 /* coder significantly whether it is .TRUE. or .FALSE., or whether it is
133 */
134 /* a constant or a variable, since it is only examined once per frame. */
135 /* Leaving it as a variable that is set to .TRUE. seems like a good */
136 /* idea, since it does enable some error-correction capability for */
137 /* unvoiced frames, with no change in the coding rate, and no noticeable
138 */
139 /* quality difference in the decoded speech. */
140 /* integer quant, nbits */
141 /* *** Read/write: variables for debugging, not needed for LPC algorithm
142 */
143
144 /* Current frame, Unstable frames, Output clip count, Max onset buffer,
145 */
146 /* Debug listing detail level, Line count on listing page */
147
148 /* nframe is not needed for an embedded LPC10 at all. */
149 /* nunsfm is initialized to 0 in SETUP, and incremented in subroutine */
150 /* ERROR, which is only called from RCCHK. When LPC10 is embedded into */
151 /* an application, I would recommend removing the call to ERROR in RCCHK,
152 */
153 /* and remove ERROR and nunsfm completely. */
154 /* iclip is initialized to 0 in SETUP, and incremented in entry SWRITE in
155 */
156 /* sread.f. When LPC10 is embedded into an application, one might want */
157 /* to cause it to be incremented in a routine that takes the output of */
158 /* SYNTHS and sends it to an audio device. It could be optionally */
159 /* displayed, for those that might want to know what it is. */
160 /* maxosp is never initialized to 0 in SETUP, although it probably should
161 */
162 /* be, and it is updated in subroutine ANALYS. I doubt that its value */
163 /* would be of much interest to an application in which LPC10 is */
164 /* embedded. */
165 /* listl and lincnt are not needed for an embedded LPC10 at all. */
166 /* integer nframe, nunsfm, iclip, maxosp, listl, lincnt */
167 /* common /contrl/ fsi, fso, fpi, fpo, fbi, fbo, pbin, fmsg, fdebug */
168 /* common /contrl/ quant, nbits */
169 /* common /contrl/ nframe, nunsfm, iclip, maxosp, listl, lincnt */
170 /* Local variables that need not be saved */
171 /* Uncoded speech parameters */
172 /* Coded speech parameters */
173 /* Others */
174 /* Local state */
175 /* None */
176 /* Parameter adjustments */
177 if (bits) {
178 --bits;
179 }
180 if (speech) {
181 --speech;
182 }
183
184 /* Function Body */
185
186 chanrd_(&c__10, &ipitv, &irms, irc, &bits[1]);
187 decode_(&ipitv, &irms, irc, voice, &pitch, &rms, rc, st);
188 synths_(voice, &pitch, &rms, rc, &speech[1], &len, st);
189 return 0;
190 } /* lpcdec_ */
191