formats/format_h263.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2006, 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 h263 data.
  22  * \arg File name extension: h263
  23  * \ingroup formats
  24  * \arg See \ref AstVideo
  25  */
  26
  27 #include "asterisk.h"
  28
  29 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  30
  31 #include "asterisk/mod_format.h"
  32 #include "asterisk/module.h"
  33 #include "asterisk/endian.h"
  34
  35 /* Some Ideas for this code came from makeh263e.c by Jeffrey Chilton */
  36
  37 /* Portions of the conversion code are by guido@sienanet.it */
  38
  39 /* According to:
  40  * http://lists.mpegif.org/pipermail/mp4-tech/2005-July/005741.html
  41  * the maximum actual frame size is not 2048, but 8192.  Since the maximum
  42  * theoretical limit is not much larger (32k = 15bits), we'll go for that
  43  * size to ensure we don't corrupt frames sent to us (unless they're
  44  * ridiculously large). */
  45 #define BUF_SIZE        32768   /* Four real h.263 Frames */
  46
  47 struct h263_desc {
  48         unsigned int lastts;
  49 };
  50
  51
  52 static int h263_open(struct ast_filestream *s)
  53 {
  54         unsigned int ts;
  55         int res;
  56
  57         if ((res = fread(&ts, 1, sizeof(ts), s->f)) < sizeof(ts)) {
  58                 ast_log(LOG_WARNING, "Empty file!\n");
  59                 return -1;
  60         }
  61         return 0;
  62 }
  63
  64 static struct ast_frame *h263_read(struct ast_filestream *s, int *whennext)
  65 {
  66         int res;
  67         int mark;
  68         unsigned short len;
  69         unsigned int ts;
  70         struct h263_desc *fs = (struct h263_desc *)s->_private;
  71
  72         /* Send a frame from the file to the appropriate channel */
  73         if ((res = fread(&len, 1, sizeof(len), s->f)) < 1)
  74                 return NULL;
  75         len = ntohs(len);
  76         mark = (len & 0x8000) ? 1 : 0;
  77         len &= 0x7fff;
  78         if (len > BUF_SIZE) {
  79                 ast_log(LOG_WARNING, "Length %d is too long\n", len);
  80                 return NULL;
  81         }
  82         s->fr.frametype = AST_FRAME_VIDEO;
  83         s->fr.subclass = AST_FORMAT_H263;
  84         s->fr.mallocd = 0;
  85         AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, len);
  86         if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
  87                 if (res)
  88                         ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
  89                 return NULL;
  90         }
  91         s->fr.samples = fs->lastts;     /* XXX what ? */
  92         s->fr.datalen = len;
  93         s->fr.subclass |= mark;
  94         s->fr.delivery.tv_sec = 0;
  95         s->fr.delivery.tv_usec = 0;
  96         if ((res = fread(&ts, 1, sizeof(ts), s->f)) == sizeof(ts)) {
  97                 fs->lastts = ntohl(ts);
  98                 *whennext = fs->lastts * 4/45;
  99         } else
 100                 *whennext = 0;
 101         return &s->fr;
 102 }
 103
 104 static int h263_write(struct ast_filestream *fs, struct ast_frame *f)
 105 {
 106         int res;
 107         unsigned int ts;
 108         unsigned short len;
 109         int subclass;
 110         int mark=0;
 111         if (f->frametype != AST_FRAME_VIDEO) {
 112                 ast_log(LOG_WARNING, "Asked to write non-video frame!\n");
 113                 return -1;
 114         }
 115         subclass = f->subclass;
 116         if (subclass & 0x1)
 117                 mark=0x8000;
 118         subclass &= ~0x1;
 119         if (subclass != AST_FORMAT_H263) {
 120                 ast_log(LOG_WARNING, "Asked to write non-h263 frame (%d)!\n", f->subclass);
 121                 return -1;
 122         }
 123         ts = htonl(f->samples);
 124         if ((res = fwrite(&ts, 1, sizeof(ts), fs->f)) != sizeof(ts)) {
 125                         ast_log(LOG_WARNING, "Bad write (%d/4): %s\n", res, strerror(errno));
 126                         return -1;
 127         }
 128         len = htons(f->datalen | mark);
 129         if ((res = fwrite(&len, 1, sizeof(len), fs->f)) != sizeof(len)) {
 130                         ast_log(LOG_WARNING, "Bad write (%d/2): %s\n", res, strerror(errno));
 131                         return -1;
 132         }
 133         if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
 134                         ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
 135                         return -1;
 136         }
 137         return 0;
 138 }
 139
 140 static int h263_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
 141 {
 142         /* No way Jose */
 143         return -1;
 144 }
 145
 146 static int h263_trunc(struct ast_filestream *fs)
 147 {
 148         /* Truncate file to current length */
 149         if (ftruncate(fileno(fs->f), ftello(fs->f)) < 0)
 150                 return -1;
 151         return 0;
 152 }
 153
 154 static off_t h263_tell(struct ast_filestream *fs)
 155 {
 156         off_t offset = ftello(fs->f);
 157         return offset;  /* XXX totally bogus, needs fixing */
 158 }
 159
 160 static const struct ast_format h263_f = {
 161         .name = "h263",
 162         .exts = "h263",
 163         .format = AST_FORMAT_H263,
 164         .open = h263_open,
 165         .write = h263_write,
 166         .seek = h263_seek,
 167         .trunc = h263_trunc,
 168         .tell = h263_tell,
 169         .read = h263_read,
 170         .buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
 171         .desc_size = sizeof(struct h263_desc),
 172 };
 173
 174 static int load_module(void)
 175 {
 176         if (ast_format_register(&h263_f))
 177                 return AST_MODULE_LOAD_FAILURE;
 178         return AST_MODULE_LOAD_SUCCESS;
 179 }
 180
 181 static int unload_module(void)
 182 {
 183         return ast_format_unregister(h263_f.name);
 184 }
 185
 186 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Raw H.263 data");