Asterisk.org: Developer Documentation (28 Oct 2009)

Wed Oct 28 15:47:54 2009

## Asterisk developer's documentation

# format_h263.c

Go to the documentation of this file.

    00001 /*
    00002  * Asterisk -- An open source telephony toolkit.
    00003  *
    00004  * Copyright (C) 1999 - 2005, Digium, Inc.
    00005  *
    00006  * Mark Spencer <markster@digium.com>
    00007  *
    00008  * See http://www.asterisk.org for more information about
    00009  * the Asterisk project. Please do not directly contact
    00010  * any of the maintainers of this project for assistance;
    00011  * the project provides a web site, mailing lists and IRC
    00012  * channels for your use.
    00013  *
    00014  * This program is free software, distributed under the terms of
    00015  * the GNU General Public License Version 2. See the LICENSE file
    00016  * at the top of the source tree.
    00017  */
    00018
    00019 /*! \file
    00020  *
    00021  * \brief Save to raw, headerless h263 data.
    00022  * \arg File name extension: h263
    00023  * \ingroup formats
    00024  */
    00025
    00026 #include <unistd.h>
    00027 #include <netinet/in.h>
    00028 #include <arpa/inet.h>
    00029 #include <stdlib.h>
    00030 #include <sys/time.h>
    00031 #include <stdio.h>
    00032 #include <errno.h>
    00033 #include <string.h>
    00034
    00035 #include "asterisk.h"
    00036
    00037 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 37808 $")
    00038
    00039 #include "asterisk/lock.h"
    00040 #include "asterisk/channel.h"
    00041 #include "asterisk/file.h"
    00042 #include "asterisk/logger.h"
    00043 #include "asterisk/sched.h"
    00044 #include "asterisk/module.h"
    00045 #include "asterisk/endian.h"
    00046
    00047 /* Some Ideas for this code came from makeh263e.c by Jeffrey Chilton */
    00048
    00049 /* Portions of the conversion code are by guido@sienanet.it */
    00050
    00051 struct ast_filestream {
    00052    void *reserved[AST_RESERVED_POINTERS];
    00053    /* Believe it or not, we must decode/recode to account for the
    00054       weird MS format */
    00055    /* This is what a filestream means to us */
    00056    FILE *f; /* Descriptor */
    00057    unsigned int lastts;
    00058    struct ast_frame fr;          /* Frame information */
    00059    char waste[AST_FRIENDLY_OFFSET]; /* Buffer for sending frames, etc */
    00060    char empty;                   /* Empty character */
    00061    unsigned char h263[32768];          /* Four real h263 Frames */
    00062 };
    00063
    00064
    00065 AST_MUTEX_DEFINE_STATIC(h263_lock);
    00066 static int glistcnt = 0;
    00067
    00068 static char *name = "h263";
    00069 static char *desc = "Raw h263 data";
    00070 static char *exts = "h263";
    00071
    00072 static struct ast_filestream *h263_open(FILE *f)
    00073 {
    00074    /* We don't have any header to read or anything really, but
    00075       if we did, it would go here.  We also might want to check
    00076       and be sure it's a valid file.  */
    00077    struct ast_filestream *tmp;
    00078    unsigned int ts;
    00079    int res;
    00080    if ((res = fread(&ts, 1, sizeof(ts), f)) < sizeof(ts)) {
    00081       ast_log(LOG_WARNING, "Empty file!\n");
    00082       return NULL;
    00083    }
    00084
    00085    if ((tmp = malloc(sizeof(struct ast_filestream)))) {
    00086       memset(tmp, 0, sizeof(struct ast_filestream));
    00087       if (ast_mutex_lock(&h263_lock)) {
    00088          ast_log(LOG_WARNING, "Unable to lock h263 list\n");
    00089          free(tmp);
    00090          return NULL;
    00091       }
    00092       tmp->f = f;
    00093       tmp->fr.data = tmp->h263;
    00094       tmp->fr.frametype = AST_FRAME_VIDEO;
    00095       tmp->fr.subclass = AST_FORMAT_H263;
    00096       /* datalen will vary for each frame */
    00097       tmp->fr.src = name;
    00098       tmp->fr.mallocd = 0;
    00099       glistcnt++;
    00100       ast_mutex_unlock(&h263_lock);
    00101       ast_update_use_count();
    00102    }
    00103    return tmp;
    00104 }
    00105
    00106 static struct ast_filestream *h263_rewrite(FILE *f, const char *comment)
    00107 {
    00108    /* We don't have any header to read or anything really, but
    00109       if we did, it would go here.  We also might want to check
    00110       and be sure it's a valid file.  */
    00111    struct ast_filestream *tmp;
    00112    if ((tmp = malloc(sizeof(struct ast_filestream)))) {
    00113       memset(tmp, 0, sizeof(struct ast_filestream));
    00114       if (ast_mutex_lock(&h263_lock)) {
    00115          ast_log(LOG_WARNING, "Unable to lock h263 list\n");
    00116          free(tmp);
    00117          return NULL;
    00118       }
    00119       tmp->f = f;
    00120       glistcnt++;
    00121       ast_mutex_unlock(&h263_lock);
    00122       ast_update_use_count();
    00123    } else
    00124       ast_log(LOG_WARNING, "Out of memory\n");
    00125    return tmp;
    00126 }
    00127
    00128 static void h263_close(struct ast_filestream *s)
    00129 {
    00130    if (ast_mutex_lock(&h263_lock)) {
    00131       ast_log(LOG_WARNING, "Unable to lock h263 list\n");
    00132       return;
    00133    }
    00134    glistcnt--;
    00135    ast_mutex_unlock(&h263_lock);
    00136    ast_update_use_count();
    00137    fclose(s->f);
    00138    free(s);
    00139    s = NULL;
    00140 }
    00141
    00142 static struct ast_frame *h263_read(struct ast_filestream *s, int *whennext)
    00143 {
    00144    int res;
    00145    int mark=0;
    00146    unsigned short len;
    00147    unsigned int ts;
    00148    /* Send a frame from the file to the appropriate channel */
    00149    s->fr.frametype = AST_FRAME_VIDEO;
    00150    s->fr.subclass = AST_FORMAT_H263;
    00151    s->fr.offset = AST_FRIENDLY_OFFSET;
    00152    s->fr.mallocd = 0;
    00153    s->fr.data = s->h263;
    00154    if ((res = fread(&len, 1, sizeof(len), s->f)) < 1) {
    00155       return NULL;
    00156    }
    00157    len = ntohs(len);
    00158    if (len & 0x8000) {
    00159       mark = 1;
    00160    }
    00161    len &= 0x7fff;
    00162    if (len > sizeof(s->h263)) {
    00163       ast_log(LOG_WARNING, "Length %d is too long\n", len);
    00164       return NULL;
    00165    }
    00166    if ((res = fread(s->h263, 1, len, s->f)) != len) {
    00167       if (res)
    00168          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
    00169       return NULL;
    00170    }
    00171    s->fr.samples = s->lastts;
    00172    s->fr.datalen = len;
    00173    s->fr.subclass |= mark;
    00174    s->fr.delivery.tv_sec = 0;
    00175    s->fr.delivery.tv_usec = 0;
    00176    if ((res = fread(&ts, 1, sizeof(ts), s->f)) == sizeof(ts)) {
    00177       s->lastts = ntohl(ts);
    00178       *whennext = s->lastts * 4/45;
    00179    } else
    00180       *whennext = 0;
    00181    return &s->fr;
    00182 }
    00183
    00184 static int h263_write(struct ast_filestream *fs, struct ast_frame *f)
    00185 {
    00186    int res;
    00187    unsigned int ts;
    00188    unsigned short len;
    00189    int subclass;
    00190    int mark=0;
    00191    if (f->frametype != AST_FRAME_VIDEO) {
    00192       ast_log(LOG_WARNING, "Asked to write non-video frame!\n");
    00193       return -1;
    00194    }
    00195    subclass = f->subclass;
    00196    if (subclass & 0x1)
    00197       mark=0x8000;
    00198    subclass &= ~0x1;
    00199    if (subclass != AST_FORMAT_H263) {
    00200       ast_log(LOG_WARNING, "Asked to write non-h263 frame (%d)!\n", f->subclass);
    00201       return -1;
    00202    }
    00203    ts = htonl(f->samples);
    00204    if ((res = fwrite(&ts, 1, sizeof(ts), fs->f)) != sizeof(ts)) {
    00205          ast_log(LOG_WARNING, "Bad write (%d/4): %s\n", res, strerror(errno));
    00206          return -1;
    00207    }
    00208    len = htons(f->datalen | mark);
    00209    if ((res = fwrite(&len, 1, sizeof(len), fs->f)) != sizeof(len)) {
    00210          ast_log(LOG_WARNING, "Bad write (%d/2): %s\n", res, strerror(errno));
    00211          return -1;
    00212    }
    00213    if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
    00214          ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
    00215          return -1;
    00216    }
    00217    return 0;
    00218 }
    00219
    00220 static char *h263_getcomment(struct ast_filestream *s)
    00221 {
    00222    return NULL;
    00223 }
    00224
    00225 static int h263_seek(struct ast_filestream *fs, long sample_offset, int whence)
    00226 {
    00227    /* No way Jose */
    00228    return -1;
    00229 }
    00230
    00231 static int h263_trunc(struct ast_filestream *fs)
    00232 {
    00233    /* Truncate file to current length */
    00234    if (ftruncate(fileno(fs->f), ftell(fs->f)) < 0)
    00235       return -1;
    00236    return 0;
    00237 }
    00238
    00239 static long h263_tell(struct ast_filestream *fs)
    00240 {
    00241    /* XXX This is totally bogus XXX */
    00242    off_t offset;
    00243    offset = ftell(fs->f);
    00244    return (offset/20)*160;
    00245 }
    00246
    00247 int load_module()
    00248 {
    00249    return ast_format_register(name, exts, AST_FORMAT_H263,
    00250                         h263_open,
    00251                         h263_rewrite,
    00252                         h263_write,
    00253                         h263_seek,
    00254                         h263_trunc,
    00255                         h263_tell,
    00256                         h263_read,
    00257                         h263_close,
    00258                         h263_getcomment);
    00259
    00260
    00261 }
    00262
    00263 int unload_module()
    00264 {
    00265    return ast_format_unregister(name);
    00266 }
    00267
    00268 int usecount()
    00269 {
    00270    return glistcnt;
    00271 }
    00272
    00273 char *description()
    00274 {
    00275    return desc;
    00276 }
    00277
    00278
    00279 char *key()
    00280 {
    00281    return ASTERISK_GPL_KEY;
    00282 }