Thu Apr 28 2011 16:57:10

Asterisk developer's documentation


format_wav_gsm.c File Reference

Save GSM in the proprietary Microsoft format. More...

#include "asterisk.h"
#include "asterisk/mod_format.h"
#include "asterisk/module.h"
#include "asterisk/endian.h"
#include "msgsm.h"
Include dependency graph for format_wav_gsm.c:

Go to the source code of this file.

Data Structures

struct  wavg_desc

Defines

#define GSM_FRAME_SIZE   33
#define GSM_SAMPLES   160
#define htoll(b)   (b)
#define htols(b)   (b)
#define ltohl(b)   (b)
#define ltohs(b)   (b)
#define MSGSM_DATA_OFFSET   60
#define MSGSM_FRAME_SIZE   65
#define MSGSM_SAMPLES   (2*GSM_SAMPLES)

Functions

static void __reg_module (void)
static void __unreg_module (void)
static int check_header (FILE *f)
static int load_module (void)
static int unload_module (void)
static int update_header (FILE *f)
static int wav_open (struct ast_filestream *s)
static struct ast_framewav_read (struct ast_filestream *s, int *whennext)
static int wav_rewrite (struct ast_filestream *s, const char *comment)
static int wav_seek (struct ast_filestream *fs, off_t sample_offset, int whence)
static off_t wav_tell (struct ast_filestream *fs)
static int wav_trunc (struct ast_filestream *fs)
static int wav_write (struct ast_filestream *s, struct ast_frame *f)
static int write_header (FILE *f)

Variables

static struct ast_module_info
__MODULE_INFO_SECTION 
__mod_info = { __MODULE_INFO_GLOBALS .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Microsoft WAV format (Proprietary GSM)" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = 10, }
static struct ast_module_infoast_module_info = &__mod_info
char msgsm_silence []
static struct ast_format wav49_f

Detailed Description

Save GSM in the proprietary Microsoft format.

Microsoft WAV format (Proprietary GSM)

  • File name extension: WAV,wav49 (Upper case WAV, lower case is another format) This format can be played on Windows systems, used for e-mail attachments mainly.

Definition in file format_wav_gsm.c.


Define Documentation

#define GSM_FRAME_SIZE   33

Definition at line 44 of file format_wav_gsm.c.

Referenced by wav_read(), and wav_write().

#define GSM_SAMPLES   160

Definition at line 47 of file format_wav_gsm.c.

Referenced by wav_read().

#define htoll (   b)    (b)

Definition at line 66 of file format_wav_gsm.c.

Referenced by update_header(), and write_header().

#define htols (   b)    (b)

Definition at line 67 of file format_wav_gsm.c.

Referenced by write_header().

#define ltohl (   b)    (b)

Definition at line 68 of file format_wav_gsm.c.

Referenced by check_header().

#define ltohs (   b)    (b)

Definition at line 69 of file format_wav_gsm.c.

Referenced by check_header().

#define MSGSM_DATA_OFFSET   60

Definition at line 46 of file format_wav_gsm.c.

Referenced by update_header(), wav_seek(), and wav_tell().

#define MSGSM_FRAME_SIZE   65

Definition at line 45 of file format_wav_gsm.c.

Referenced by update_header(), wav_read(), wav_seek(), wav_tell(), wav_write(), and write_header().

#define MSGSM_SAMPLES   (2*GSM_SAMPLES)

Definition at line 48 of file format_wav_gsm.c.

Referenced by update_header(), wav_seek(), wav_tell(), and write_header().


Function Documentation

static void __reg_module ( void  ) [static]

Definition at line 555 of file format_wav_gsm.c.

static void __unreg_module ( void  ) [static]

Definition at line 555 of file format_wav_gsm.c.

static int check_header ( FILE *  f) [static]

Definition at line 88 of file format_wav_gsm.c.

References ast_log(), DEFAULT_SAMPLE_RATE, format, LOG_WARNING, ltohl, ltohs, and type.

Referenced by wav_open().

{
   int type, size, formtype;
   int fmt, hsize, fact;
   short format, chans;
   int freq;
   int data;
   if (fread(&type, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (type)\n");
      return -1;
   }
   if (fread(&size, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (size)\n");
      return -1;
   }
   size = ltohl(size);
   if (fread(&formtype, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (formtype)\n");
      return -1;
   }
   if (memcmp(&type, "RIFF", 4)) {
      ast_log(LOG_WARNING, "Does not begin with RIFF\n");
      return -1;
   }
   if (memcmp(&formtype, "WAVE", 4)) {
      ast_log(LOG_WARNING, "Does not contain WAVE\n");
      return -1;
   }
   if (fread(&fmt, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (fmt)\n");
      return -1;
   }
   if (memcmp(&fmt, "fmt ", 4)) {
      ast_log(LOG_WARNING, "Does not say fmt\n");
      return -1;
   }
   if (fread(&hsize, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (formtype)\n");
      return -1;
   }
   if (ltohl(hsize) != 20) {
      ast_log(LOG_WARNING, "Unexpected header size %d\n", ltohl(hsize));
      return -1;
   }
   if (fread(&format, 1, 2, f) != 2) {
      ast_log(LOG_WARNING, "Read failed (format)\n");
      return -1;
   }
   if (ltohs(format) != 49) {
      ast_log(LOG_WARNING, "Not a GSM file %d\n", ltohs(format));
      return -1;
   }
   if (fread(&chans, 1, 2, f) != 2) {
      ast_log(LOG_WARNING, "Read failed (format)\n");
      return -1;
   }
   if (ltohs(chans) != 1) {
      ast_log(LOG_WARNING, "Not in mono %d\n", ltohs(chans));
      return -1;
   }
   if (fread(&freq, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (freq)\n");
      return -1;
   }
   if (ltohl(freq) != DEFAULT_SAMPLE_RATE) {
      ast_log(LOG_WARNING, "Unexpected frequency %d\n", ltohl(freq));
      return -1;
   }
   /* Ignore the byte frequency */
   if (fread(&freq, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (X_1)\n");
      return -1;
   }
   /* Ignore the two weird fields */
   if (fread(&freq, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (X_2/X_3)\n");
      return -1;
   }
   /* Ignore the byte frequency */
   if (fread(&freq, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (Y_1)\n");
      return -1;
   }
   /* Check for the word fact */
   if (fread(&fact, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (fact)\n");
      return -1;
   }
   if (memcmp(&fact, "fact", 4)) {
      ast_log(LOG_WARNING, "Does not say fact\n");
      return -1;
   }
   /* Ignore the "fact value" */
   if (fread(&fact, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (fact header)\n");
      return -1;
   }
   if (fread(&fact, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (fact value)\n");
      return -1;
   }
   /* Check for the word data */
   if (fread(&data, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (data)\n");
      return -1;
   }
   if (memcmp(&data, "data", 4)) {
      ast_log(LOG_WARNING, "Does not say data\n");
      return -1;
   }
   /* Ignore the data length */
   if (fread(&data, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Read failed (data)\n");
      return -1;
   }
   return 0;
}
static int load_module ( void  ) [static]
static int unload_module ( void  ) [static]

Definition at line 546 of file format_wav_gsm.c.

References ast_format_unregister(), and ast_format::name.

static int update_header ( FILE *  f) [static]

Definition at line 206 of file format_wav_gsm.c.

References ast_log(), fwrite, htoll, LOG_WARNING, MSGSM_DATA_OFFSET, MSGSM_FRAME_SIZE, and MSGSM_SAMPLES.

Referenced by wav_trunc(), and wav_write().

{
   off_t cur,end,bytes;
   int datalen, filelen, samples;

   cur = ftello(f);
   fseek(f, 0, SEEK_END);
   end = ftello(f);
   /* in a gsm WAV, data starts 60 bytes in */
   bytes = end - MSGSM_DATA_OFFSET;
   samples = htoll(bytes / MSGSM_FRAME_SIZE * MSGSM_SAMPLES);
   datalen = htoll(bytes);
   filelen = htoll(MSGSM_DATA_OFFSET - 8 + bytes);
   if (cur < 0) {
      ast_log(LOG_WARNING, "Unable to find our position\n");
      return -1;
   }
   if (fseek(f, 4, SEEK_SET)) {
      ast_log(LOG_WARNING, "Unable to set our position\n");
      return -1;
   }
   if (fwrite(&filelen, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write file size\n");
      return -1;
   }
   if (fseek(f, 48, SEEK_SET)) {
      ast_log(LOG_WARNING, "Unable to set our position\n");
      return -1;
   }
   if (fwrite(&samples, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write samples\n");
      return -1;
   }
   if (fseek(f, 56, SEEK_SET)) {
      ast_log(LOG_WARNING, "Unable to set our position\n");
      return -1;
   }
   if (fwrite(&datalen, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write datalen\n");
      return -1;
   }
   if (fseeko(f, cur, SEEK_SET)) {
      ast_log(LOG_WARNING, "Unable to return to position\n");
      return -1;
   }
   return 0;
}
static int wav_open ( struct ast_filestream s) [static]

Definition at line 368 of file format_wav_gsm.c.

References ast_filestream::_private, check_header(), ast_filestream::f, and wavg_desc::secondhalf.

{
   /* We don't have any header to read or anything really, but
      if we did, it would go here.  We also might want to check
      and be sure it's a valid file.  */
   struct wavg_desc *fs = (struct wavg_desc *)s->_private;

   if (check_header(s->f))
      return -1;
   fs->secondhalf = 0;  /* not strictly necessary */
   return 0;
}
static struct ast_frame* wav_read ( struct ast_filestream s,
int *  whennext 
) [static, read]

Definition at line 392 of file format_wav_gsm.c.

References ast_filestream::_private, AST_FORMAT_GSM, AST_FRAME_SET_BUFFER, AST_FRAME_VOICE, AST_FRIENDLY_OFFSET, ast_log(), ast_filestream::buf, conv65(), ast_frame::data, errno, ast_filestream::f, ast_filestream::fr, ast_frame::frametype, GSM_FRAME_SIZE, GSM_SAMPLES, LOG_WARNING, ast_frame::mallocd, MSGSM_FRAME_SIZE, ast_frame::offset, ast_frame::ptr, ast_frame::samples, wavg_desc::secondhalf, and ast_frame::subclass.

{
   /* Send a frame from the file to the appropriate channel */
   struct wavg_desc *fs = (struct wavg_desc *)s->_private;

   s->fr.frametype = AST_FRAME_VOICE;
   s->fr.subclass = AST_FORMAT_GSM;
   s->fr.offset = AST_FRIENDLY_OFFSET;
   s->fr.samples = GSM_SAMPLES;
   s->fr.mallocd = 0;
   AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE);
   if (fs->secondhalf) {
      /* Just return a frame based on the second GSM frame */
      s->fr.data.ptr = (char *)s->fr.data.ptr + GSM_FRAME_SIZE;
      s->fr.offset += GSM_FRAME_SIZE;
   } else {
      /* read and convert */
      unsigned char msdata[MSGSM_FRAME_SIZE];
      int res;
      
      if ((res = fread(msdata, 1, MSGSM_FRAME_SIZE, s->f)) != MSGSM_FRAME_SIZE) {
         if (res && (res != 1))
            ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
         return NULL;
      }
      /* Convert from MS format to two real GSM frames */
      conv65(msdata, s->fr.data.ptr);
   }
   fs->secondhalf = !fs->secondhalf;
   *whennext = GSM_SAMPLES;
   return &s->fr;
}
static int wav_rewrite ( struct ast_filestream s,
const char *  comment 
) [static]

Definition at line 381 of file format_wav_gsm.c.

References ast_filestream::f, and write_header().

{
   /* We don't have any header to read or anything really, but
      if we did, it would go here.  We also might want to check
      and be sure it's a valid file.  */

   if (write_header(s->f))
      return -1;
   return 0;
}
static int wav_seek ( struct ast_filestream fs,
off_t  sample_offset,
int  whence 
) [static]

Definition at line 472 of file format_wav_gsm.c.

References ast_filestream::_private, ast_log(), errno, ast_filestream::f, fwrite, LOG_WARNING, MSGSM_DATA_OFFSET, MSGSM_FRAME_SIZE, MSGSM_SAMPLES, s, wavg_desc::secondhalf, and SEEK_FORCECUR.

{
   off_t offset=0, distance, max;
   struct wavg_desc *s = (struct wavg_desc *)fs->_private;

   off_t min = MSGSM_DATA_OFFSET;
   off_t cur = ftello(fs->f);
   fseek(fs->f, 0, SEEK_END);
   max = ftello(fs->f); /* XXX ideally, should round correctly */
   /* Compute the distance in bytes, rounded to the block size */
   distance = (sample_offset/MSGSM_SAMPLES) * MSGSM_FRAME_SIZE;
   if (whence == SEEK_SET)
      offset = distance + min;
   else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
      offset = distance + cur;
   else if (whence == SEEK_END)
      offset = max - distance;
   /* always protect against seeking past end of header */
   if (offset < min)
      offset = min;
   if (whence != SEEK_FORCECUR) {
      if (offset > max)
         offset = max;
   } else if (offset > max) {
      int i;
      fseek(fs->f, 0, SEEK_END);
      for (i=0; i< (offset - max) / MSGSM_FRAME_SIZE; i++) {
         if (!fwrite(msgsm_silence, 1, MSGSM_FRAME_SIZE, fs->f)) {
            ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
         }
      }
   }
   s->secondhalf = 0;
   return fseeko(fs->f, offset, SEEK_SET);
}
static off_t wav_tell ( struct ast_filestream fs) [static]

Definition at line 515 of file format_wav_gsm.c.

References ast_filestream::f, MSGSM_DATA_OFFSET, MSGSM_FRAME_SIZE, and MSGSM_SAMPLES.

{
   off_t offset;
   offset = ftello(fs->f);
   /* since this will most likely be used later in play or record, lets stick
    * to that level of resolution, just even frames boundaries */
   return (offset - MSGSM_DATA_OFFSET)/MSGSM_FRAME_SIZE*MSGSM_SAMPLES;
}
static int wav_trunc ( struct ast_filestream fs) [static]

Definition at line 508 of file format_wav_gsm.c.

References ast_filestream::f, and update_header().

{
   if (ftruncate(fileno(fs->f), ftello(fs->f)))
      return -1;
   return update_header(fs->f);
}
static int wav_write ( struct ast_filestream s,
struct ast_frame f 
) [static]

Definition at line 425 of file format_wav_gsm.c.

References ast_filestream::_private, AST_FORMAT_GSM, AST_FRAME_VOICE, ast_log(), ast_filestream::buf, conv66(), ast_frame::data, ast_frame::datalen, errno, ast_filestream::f, ast_frame::frametype, fwrite, GSM_FRAME_SIZE, len(), LOG_WARNING, MSGSM_FRAME_SIZE, ast_frame::ptr, wavg_desc::secondhalf, ast_frame::subclass, and update_header().

{
   int len;
   int size;
   struct wavg_desc *fs = (struct wavg_desc *)s->_private;

   if (f->frametype != AST_FRAME_VOICE) {
      ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
      return -1;
   }
   if (f->subclass != AST_FORMAT_GSM) {
      ast_log(LOG_WARNING, "Asked to write non-GSM frame (%d)!\n", f->subclass);
      return -1;
   }
   /* XXX this might fail... if the input is a multiple of MSGSM_FRAME_SIZE
    * we assume it is already in the correct format.
    */
   if (!(f->datalen % MSGSM_FRAME_SIZE)) {
      size = MSGSM_FRAME_SIZE;
      fs->secondhalf = 0;
   } else {
      size = GSM_FRAME_SIZE;
   }
   for (len = 0; len < f->datalen ; len += size) {
      int res;
      unsigned char *src, msdata[MSGSM_FRAME_SIZE];
      if (fs->secondhalf) {   /* second half of raw gsm to be converted */
         memcpy(s->buf + GSM_FRAME_SIZE, f->data.ptr + len, GSM_FRAME_SIZE);
         conv66((unsigned char *) s->buf, msdata);
         src = msdata;
         fs->secondhalf = 0;
      } else if (size == GSM_FRAME_SIZE) {   /* first half of raw gsm */
         memcpy(s->buf, f->data.ptr + len, GSM_FRAME_SIZE);
         src = NULL; /* nothing to write */
         fs->secondhalf = 1;
      } else { /* raw msgsm data */
         src = f->data.ptr + len;
      }
      if (src && (res = fwrite(src, 1, MSGSM_FRAME_SIZE, s->f)) != MSGSM_FRAME_SIZE) {
         ast_log(LOG_WARNING, "Bad write (%d/65): %s\n", res, strerror(errno));
         return -1;
      }
      update_header(s->f); /* XXX inefficient! */
   }
   return 0;
}
static int write_header ( FILE *  f) [static]

Definition at line 254 of file format_wav_gsm.c.

References ast_log(), fwrite, htoll, htols, LOG_WARNING, MSGSM_FRAME_SIZE, and MSGSM_SAMPLES.

Referenced by wav_rewrite().

{
   /* Samples per second (always 8000 for this format). */
   unsigned int sample_rate = htoll(8000);
   /* Bytes per second (always 1625 for this format). */
   unsigned int byte_sample_rate = htoll(1625);
   /* This is the size of the "fmt " subchunk */
   unsigned int fmtsize = htoll(20);
   /* WAV #49 */
   unsigned short fmt = htols(49);
   /* Mono = 1 channel */
   unsigned short chans = htols(1);
   /* Each block of data is exactly 65 bytes in size. */
   unsigned int block_align = htoll(MSGSM_FRAME_SIZE);
   /* Not actually 2, but rounded up to the nearest bit */
   unsigned short bits_per_sample = htols(2);
   /* Needed for compressed formats */
   unsigned short extra_format = htols(MSGSM_SAMPLES);
   /* This is the size of the "fact" subchunk */
   unsigned int factsize = htoll(4);
   /* Number of samples in the data chunk */
   unsigned int num_samples = htoll(0);
   /* Number of bytes in the data chunk */
   unsigned int size = htoll(0);
   /* Write a GSM header, ignoring sizes which will be filled in later */

   /*  0: Chunk ID */
   if (fwrite("RIFF", 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /*  4: Chunk Size */
   if (fwrite(&size, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /*  8: Chunk Format */
   if (fwrite("WAVE", 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 12: Subchunk 1: ID */
   if (fwrite("fmt ", 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 16: Subchunk 1: Size (minus 8) */
   if (fwrite(&fmtsize, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 20: Subchunk 1: Audio format (49) */
   if (fwrite(&fmt, 1, 2, f) != 2) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 22: Subchunk 1: Number of channels */
   if (fwrite(&chans, 1, 2, f) != 2) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 24: Subchunk 1: Sample rate */
   if (fwrite(&sample_rate, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 28: Subchunk 1: Byte rate */
   if (fwrite(&byte_sample_rate, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 32: Subchunk 1: Block align */
   if (fwrite(&block_align, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 36: Subchunk 1: Bits per sample */
   if (fwrite(&bits_per_sample, 1, 2, f) != 2) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 38: Subchunk 1: Extra format bytes */
   if (fwrite(&extra_format, 1, 2, f) != 2) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 40: Subchunk 2: ID */
   if (fwrite("fact", 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 44: Subchunk 2: Size (minus 8) */
   if (fwrite(&factsize, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 48: Subchunk 2: Number of samples */
   if (fwrite(&num_samples, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 52: Subchunk 3: ID */
   if (fwrite("data", 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   /* 56: Subchunk 3: Size */
   if (fwrite(&size, 1, 4, f) != 4) {
      ast_log(LOG_WARNING, "Unable to write header\n");
      return -1;
   }
   return 0;
}

Variable Documentation

struct ast_module_info __MODULE_INFO_SECTION __mod_info = { __MODULE_INFO_GLOBALS .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Microsoft WAV format (Proprietary GSM)" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = 10, } [static]

Definition at line 555 of file format_wav_gsm.c.

Definition at line 555 of file format_wav_gsm.c.

char msgsm_silence[]

Definition at line 51 of file format_wav_gsm.c.

struct ast_format wav49_f [static]

Definition at line 524 of file format_wav_gsm.c.