Wed Jan 8 2020 09:49:47

Asterisk developer's documentation


format_h264.c
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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 h264 data.
22  * \arg File name extension: h264
23  * \ingroup formats
24  * \arg See \ref AstVideo
25  */
26 
27 /*** MODULEINFO
28  <support_level>core</support_level>
29  ***/
30 
31 #include "asterisk.h"
32 
33 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 364578 $")
34 
35 #include "asterisk/mod_format.h"
36 #include "asterisk/module.h"
37 #include "asterisk/endian.h"
38 
39 /* Some Ideas for this code came from makeh264e.c by Jeffrey Chilton */
40 
41 /* Portions of the conversion code are by guido@sienanet.it */
42 /*! \todo Check this buf size estimate, it may be totally wrong for large frame video */
43 
44 #define BUF_SIZE 4096 /* Two Real h264 Frames */
45 struct h264_desc {
46  unsigned int lastts;
47 };
48 
49 static int h264_open(struct ast_filestream *s)
50 {
51  unsigned int ts;
52  int res;
53  if ((res = fread(&ts, 1, sizeof(ts), s->f)) < sizeof(ts)) {
54  ast_log(LOG_WARNING, "Empty file!\n");
55  return -1;
56  }
57  return 0;
58 }
59 
60 static struct ast_frame *h264_read(struct ast_filestream *s, int *whennext)
61 {
62  int res;
63  int mark=0;
64  unsigned short len;
65  unsigned int ts;
66  struct h264_desc *fs = (struct h264_desc *)s->_private;
67 
68  /* Send a frame from the file to the appropriate channel */
69  if ((res = fread(&len, 1, sizeof(len), s->f)) < 1)
70  return NULL;
71  len = ntohs(len);
72  mark = (len & 0x8000) ? 1 : 0;
73  len &= 0x7fff;
74  if (len > BUF_SIZE) {
75  ast_log(LOG_WARNING, "Length %d is too long\n", len);
76  len = BUF_SIZE; /* XXX truncate */
77  }
80  s->fr.mallocd = 0;
82  if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
83  if (res)
84  ast_log(LOG_WARNING, "Short read (%d of %d) (%s)!\n", res, len, strerror(errno));
85  return NULL;
86  }
87  s->fr.samples = fs->lastts;
88  s->fr.datalen = len;
89  s->fr.subclass.codec |= mark;
90  s->fr.delivery.tv_sec = 0;
91  s->fr.delivery.tv_usec = 0;
92  if ((res = fread(&ts, 1, sizeof(ts), s->f)) == sizeof(ts)) {
93  fs->lastts = ntohl(ts);
94  *whennext = fs->lastts * 4/45;
95  } else
96  *whennext = 0;
97  return &s->fr;
98 }
99 
100 static int h264_write(struct ast_filestream *s, struct ast_frame *f)
101 {
102  int res;
103  unsigned int ts;
104  unsigned short len;
105  int mark;
106 
107  if (f->frametype != AST_FRAME_VIDEO) {
108  ast_log(LOG_WARNING, "Asked to write non-video frame!\n");
109  return -1;
110  }
111  mark = (f->subclass.codec & 0x1) ? 0x8000 : 0;
112  if ((f->subclass.codec & ~0x1) != AST_FORMAT_H264) {
113  ast_log(LOG_WARNING, "Asked to write non-h264 frame (%s)!\n", ast_getformatname(f->subclass.codec));
114  return -1;
115  }
116  ts = htonl(f->samples);
117  if ((res = fwrite(&ts, 1, sizeof(ts), s->f)) != sizeof(ts)) {
118  ast_log(LOG_WARNING, "Bad write (%d/4): %s\n", res, strerror(errno));
119  return -1;
120  }
121  len = htons(f->datalen | mark);
122  if ((res = fwrite(&len, 1, sizeof(len), s->f)) != sizeof(len)) {
123  ast_log(LOG_WARNING, "Bad write (%d/2): %s\n", res, strerror(errno));
124  return -1;
125  }
126  if ((res = fwrite(f->data.ptr, 1, f->datalen, s->f)) != f->datalen) {
127  ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
128  return -1;
129  }
130  return 0;
131 }
132 
133 static int h264_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
134 {
135  /* No way Jose */
136  return -1;
137 }
138 
139 static int h264_trunc(struct ast_filestream *fs)
140 {
141  int fd;
142  off_t cur;
143 
144  if ((fd = fileno(fs->f)) < 0) {
145  ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for h264 filestream %p: %s\n", fs, strerror(errno));
146  return -1;
147  }
148  if ((cur = ftello(fs->f)) < 0) {
149  ast_log(AST_LOG_WARNING, "Unable to determine current position in h264 filestream %p: %s\n", fs, strerror(errno));
150  return -1;
151  }
152  /* Truncate file to current length */
153  return ftruncate(fd, cur);
154 }
155 
156 static off_t h264_tell(struct ast_filestream *fs)
157 {
158  off_t offset = ftell(fs->f);
159  return offset; /* XXX totally bogus, needs fixing */
160 }
161 
162 static const struct ast_format h264_f = {
163  .name = "h264",
164  .exts = "h264",
165  .format = AST_FORMAT_H264,
166  .open = h264_open,
167  .write = h264_write,
168  .seek = h264_seek,
169  .trunc = h264_trunc,
170  .tell = h264_tell,
171  .read = h264_read,
172  .buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
173  .desc_size = sizeof(struct h264_desc),
174 };
175 
176 static int load_module(void)
177 {
178  if (ast_format_register(&h264_f))
181 }
182 
183 static int unload_module(void)
184 {
185  return ast_format_unregister(h264_f.name);
186 }
187 
189  .load = load_module,
190  .unload = unload_module,
191  .load_pri = AST_MODPRI_APP_DEPEND
192 );
union ast_frame_subclass subclass
Definition: frame.h:146
Asterisk main include file. File version handling, generic pbx functions.
#define ast_format_register(f)
Definition: mod_format.h:131
#define BUF_SIZE
Definition: format_h264.c:44
void * ptr
Definition: frame.h:160
#define LOG_WARNING
Definition: logger.h:144
static struct ast_frame * h264_read(struct ast_filestream *s, int *whennext)
Definition: format_h264.c:60
#define AST_LOG_WARNING
Definition: logger.h:149
static int load_module(void)
Definition: format_h264.c:176
long ts
Definition: frame.h:168
Each supported file format is described by the following structure.
Definition: mod_format.h:43
static int unload_module(void)
Definition: format_h264.c:183
#define AST_MODULE_INFO(keystr, flags_to_set, desc, fields...)
Definition: module.h:374
static off_t h264_tell(struct ast_filestream *fs)
Definition: format_h264.c:156
format_t codec
Definition: frame.h:137
#define AST_FRAME_SET_BUFFER(fr, _base, _ofs, _datalen)
Definition: frame.h:183
#define AST_FRIENDLY_OFFSET
Offset into a frame&#39;s data buffer.
Definition: frame.h:204
static struct ast_format h264_f
Definition: format_h264.c:162
Asterisk architecture endianess compatibility definitions.
int datalen
Definition: frame.h:148
struct ast_frame fr
Definition: mod_format.h:117
static int h264_open(struct ast_filestream *s)
Definition: format_h264.c:49
void * _private
Definition: mod_format.h:119
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 len(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t buflen)
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 h264_write(struct ast_filestream *s, struct ast_frame *f)
Definition: format_h264.c:100
unsigned int lastts
Definition: format_h264.c:46
int errno
static struct ast_format f[]
Definition: format_g726.c:181
if(yyss+yystacksize-1<=yyssp)
Definition: ast_expr2.c:1874
struct timeval delivery
Definition: frame.h:162
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
static int h264_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
Definition: format_h264.c:133
Data structure associated with a single frame of data.
Definition: frame.h:142
enum ast_frame_type frametype
Definition: frame.h:144
#define AST_FORMAT_H264
Definition: frame.h:287
#define ASTERISK_GPL_KEY
The text the key() function should return.
Definition: module.h:38
Asterisk module definitions.
union ast_frame::@172 data
static int h264_trunc(struct ast_filestream *fs)
Definition: format_h264.c:139
#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