Wed Jan 8 2020 09:49:47

Asterisk developer's documentation


format_g729.c
Go to the documentation of this file.
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 1999 - 2005, Digium, Inc.
5  *
6  * Mark Spencer <markster@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18 
19 /*! \file
20  *
21  * \brief Save to raw, headerless G729 data.
22  * \note This is not an encoder/decoder. The codec fo g729 is only
23  * available with a commercial license from Digium, due to patent
24  * restrictions. Check http://www.digium.com for information.
25  * \arg Extensions: g729
26  * \ingroup formats
27  */
28 
29 /*** MODULEINFO
30  <support_level>core</support_level>
31  ***/
32 
33 #include "asterisk.h"
34 
35 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 364578 $")
36 
37 #include "asterisk/mod_format.h"
38 #include "asterisk/module.h"
39 #include "asterisk/endian.h"
40 
41 /* Some Ideas for this code came from makeg729e.c by Jeffrey Chilton */
42 
43 /* Portions of the conversion code are by guido@sienanet.it */
44 
45 #define BUF_SIZE 20 /* two G729 frames */
46 #define G729A_SAMPLES 160
47 
48 static struct ast_frame *g729_read(struct ast_filestream *s, int *whennext)
49 {
50  int res;
51  /* Send a frame from the file to the appropriate channel */
54  s->fr.mallocd = 0;
57  if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
58  if (res && (res != 10)) /* XXX what for ? */
59  ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
60  return NULL;
61  }
62  *whennext = s->fr.samples;
63  return &s->fr;
64 }
65 
66 static int g729_write(struct ast_filestream *fs, struct ast_frame *f)
67 {
68  int res;
69  if (f->frametype != AST_FRAME_VOICE) {
70  ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
71  return -1;
72  }
73  if (f->subclass.codec != AST_FORMAT_G729A) {
74  ast_log(LOG_WARNING, "Asked to write non-G729 frame (%s)!\n", ast_getformatname(f->subclass.codec));
75  return -1;
76  }
77  if (f->datalen % 10) {
78  ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 10\n", f->datalen);
79  return -1;
80  }
81  if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
82  ast_log(LOG_WARNING, "Bad write (%d/10): %s\n", res, strerror(errno));
83  return -1;
84  }
85  return 0;
86 }
87 
88 static int g729_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
89 {
90  long bytes;
91  off_t min,cur,max,offset=0;
92  min = 0;
93  cur = ftello(fs->f);
94  fseeko(fs->f, 0, SEEK_END);
95  max = ftello(fs->f);
96 
97  bytes = BUF_SIZE * (sample_offset / G729A_SAMPLES);
98  if (whence == SEEK_SET)
99  offset = bytes;
100  else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
101  offset = cur + bytes;
102  else if (whence == SEEK_END)
103  offset = max - bytes;
104  if (whence != SEEK_FORCECUR) {
105  offset = (offset > max)?max:offset;
106  }
107  /* protect against seeking beyond begining. */
108  offset = (offset < min)?min:offset;
109  if (fseeko(fs->f, offset, SEEK_SET) < 0)
110  return -1;
111  return 0;
112 }
113 
114 static int g729_trunc(struct ast_filestream *fs)
115 {
116  int fd;
117  off_t cur;
118 
119  if ((fd = fileno(fs->f)) < 0) {
120  ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for g729 filestream %p: %s\n", fs, strerror(errno));
121  return -1;
122  }
123  if ((cur = ftello(fs->f)) < 0) {
124  ast_log(AST_LOG_WARNING, "Unable to determine current position in g729 filestream %p: %s\n", fs, strerror(errno));
125  return -1;
126  }
127  /* Truncate file to current length */
128  return ftruncate(fd, cur);
129 }
130 
131 static off_t g729_tell(struct ast_filestream *fs)
132 {
133  off_t offset = ftello(fs->f);
134  return (offset/BUF_SIZE)*G729A_SAMPLES;
135 }
136 
137 static const struct ast_format g729_f = {
138  .name = "g729",
139  .exts = "g729",
140  .format = AST_FORMAT_G729A,
141  .write = g729_write,
142  .seek = g729_seek,
143  .trunc = g729_trunc,
144  .tell = g729_tell,
145  .read = g729_read,
146  .buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
147 };
148 
149 static int load_module(void)
150 {
151  if (ast_format_register(&g729_f))
154 }
155 
156 static int unload_module(void)
157 {
158  return ast_format_unregister(g729_f.name);
159 }
160 
162  .load = load_module,
163  .unload = unload_module,
164  .load_pri = AST_MODPRI_APP_DEPEND
165 );
union ast_frame_subclass subclass
Definition: frame.h:146
#define BUF_SIZE
Definition: format_g729.c:45
Asterisk main include file. File version handling, generic pbx functions.
#define ast_format_register(f)
Definition: mod_format.h:131
int offset
Definition: frame.h:156
#define G729A_SAMPLES
Definition: format_g729.c:46
void * ptr
Definition: frame.h:160
static int g729_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
Definition: format_g729.c:88
#define LOG_WARNING
Definition: logger.h:144
#define AST_LOG_WARNING
Definition: logger.h:149
static struct ast_frame * g729_read(struct ast_filestream *s, int *whennext)
Definition: format_g729.c:48
Each supported file format is described by the following structure.
Definition: mod_format.h:43
#define AST_MODULE_INFO(keystr, flags_to_set, desc, fields...)
Definition: module.h:374
format_t codec
Definition: frame.h:137
#define AST_FORMAT_G729A
Definition: frame.h:258
#define AST_FRAME_SET_BUFFER(fr, _base, _ofs, _datalen)
Definition: frame.h:183
static int unload_module(void)
Definition: format_g729.c:156
#define AST_FRIENDLY_OFFSET
Offset into a frame&#39;s data buffer.
Definition: frame.h:204
Asterisk architecture endianess compatibility definitions.
int datalen
Definition: frame.h:148
struct ast_frame fr
Definition: mod_format.h:117
int ast_format_unregister(const char *name)
Unregisters a file format.
Definition: file.c:104
char * ast_getformatname(format_t format)
Get the name of a format.
Definition: frame.c:578
char name[80]
Definition: mod_format.h:44
static int load_module(void)
Definition: format_g729.c:149
static int g729_trunc(struct ast_filestream *fs)
Definition: format_g729.c:114
void ast_log(int level, const char *file, int line, const char *function, const char *fmt,...)
Used for sending a log message This is the standard logger function. Probably the only way you will i...
Definition: logger.c:1207
static int g729_write(struct ast_filestream *fs, struct ast_frame *f)
Definition: format_g729.c:66
int errno
#define SEEK_FORCECUR
Definition: file.h:50
static off_t g729_tell(struct ast_filestream *fs)
Definition: format_g729.c:131
static struct ast_format g729_f
Definition: format_g729.c:137
static struct ast_format f[]
Definition: format_g726.c:181
int mallocd
Definition: frame.h:152
This structure is allocated by file.c in one chunk, together with buf_size and desc_size bytes of mem...
Definition: mod_format.h:100
Data structure associated with a single frame of data.
Definition: frame.h:142
enum ast_frame_type frametype
Definition: frame.h:144
#define ASTERISK_GPL_KEY
The text the key() function should return.
Definition: module.h:38
Asterisk module definitions.
union ast_frame::@172 data
#define ASTERISK_FILE_VERSION(file, version)
Register/unregister a source code file with the core.
Definition: asterisk.h:180
int samples
Definition: frame.h:150