Sat Nov 1 06:29:05 2008

Asterisk developer's documentation

formats

format_pcm.c File Reference

Flat, binary, ulaw PCM file format. More...

#include "asterisk.h"
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/time.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include "asterisk/lock.h"
#include "asterisk/channel.h"
#include "asterisk/file.h"
#include "asterisk/logger.h"
#include "asterisk/sched.h"
#include "asterisk/module.h"
#include "asterisk/endian.h"
#include "asterisk/ulaw.h"
#include "asterisk/alaw.h"

Include dependency graph for format_pcm.c:

Go to the source code of this file.

Defines

#define AU_ENC_8BIT_ULAW   1
#define AU_HDR_CHANNELS_OFF   5
#define AU_HDR_DATA_SIZE_OFF   2
#define AU_HDR_ENCODING_OFF   3
#define AU_HDR_HDR_SIZE_OFF   1
#define AU_HDR_MAGIC_OFF   0
#define AU_HDR_SAMPLE_RATE_OFF   4
#define AU_HEADER(var)   uint32_t var[6]
#define AU_HEADER_SIZE   24
#define AU_MAGIC   0x2e736e64
#define BUF_SIZE   160
#define htoll(b)   (b)
#define htols(b)   (b)
#define ltohl(b)   (b)
#define ltohs(b)   (b)

Functions

 AST_MODULE_INFO_STANDARD (ASTERISK_GPL_KEY,"Raw/Sun uLaw/ALaw 8KHz (PCM,PCMA,AU), G.722 16Khz")
static int au_open (struct ast_filestream *s)
static int au_rewrite (struct ast_filestream *s, const char *comment)
static int au_seek (struct ast_filestream *fs, off_t sample_offset, int whence)
static off_t au_tell (struct ast_filestream *fs)
static int au_trunc (struct ast_filestream *fs)
static int check_header (FILE *f)
static int load_module (void)
static struct ast_frame * pcm_read (struct ast_filestream *s, int *whennext)
static int pcm_seek (struct ast_filestream *fs, off_t sample_offset, int whence)
static off_t pcm_tell (struct ast_filestream *fs)
static int pcm_trunc (struct ast_filestream *fs)
static int pcm_write (struct ast_filestream *fs, struct ast_frame *f)
static int unload_module (void)
static int update_header (FILE *f)
static int write_header (FILE *f)

Variables

static struct ast_format alaw_f
static char alaw_silence [BUF_SIZE]
static struct ast_format au_f
static struct ast_format g722_f
static struct ast_format pcm_f
static char ulaw_silence [BUF_SIZE]

Detailed Description

Flat, binary, ulaw PCM file format.

Definition in file format_pcm.c.

Define Documentation

#define AU_ENC_8BIT_ULAW   1

Definition at line 244 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_CHANNELS_OFF   5

Definition at line 242 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_DATA_SIZE_OFF   2

Definition at line 239 of file format_pcm.c.

Referenced by update_header(), and write_header().

#define AU_HDR_ENCODING_OFF   3

Definition at line 240 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_HDR_SIZE_OFF   1

Definition at line 238 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_MAGIC_OFF   0

Definition at line 237 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_SAMPLE_RATE_OFF   4

Definition at line 241 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HEADER ( var   )     uint32_t var[6]

Definition at line 235 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HEADER_SIZE   24

Definition at line 234 of file format_pcm.c.

Referenced by au_seek(), au_tell(), check_header(), update_header(), and write_header().

#define AU_MAGIC   0x2e736e64

Definition at line 246 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define BUF_SIZE   160

Definition at line 50 of file format_pcm.c.

#define htoll ( b   )     (b)

Definition at line 248 of file format_pcm.c.

Referenced by update_header(), and write_header().

#define htols ( b   )     (b)

Definition at line 249 of file format_pcm.c.

Referenced by write_header().

#define ltohl ( b   )     (b)

Definition at line 250 of file format_pcm.c.

Referenced by check_header().

#define ltohs ( b   )     (b)

Definition at line 251 of file format_pcm.c.

Referenced by check_header().

Function Documentation

AST_MODULE_INFO_STANDARD ( ASTERISK_GPL_KEY  ,
"Raw/Sun uLaw/ALaw 8KHz   (PCM,PCMA,AU),
G.722 16Khz"   
)

static int au_open ( struct ast_filestream *  s  )  [static]

Definition at line 369 of file format_pcm.c.

References check_header(), and s.

00370 {
00371    if (check_header(s->f) < 0)
00372       return -1;
00373    return 0;
00374 }

static int au_rewrite ( struct ast_filestream *  s,
const char *  comment 
) [static]

Definition at line 376 of file format_pcm.c.

References s, and write_header().

00377 {
00378    if (write_header(s->f))
00379       return -1;
00380    return 0;
00381 }

static int au_seek ( struct ast_filestream *  fs,
off_t  sample_offset,
int  whence 
) [static]

Definition at line 384 of file format_pcm.c.

References AST_FORMAT_G722, AU_HEADER_SIZE, ast_filestream::f, ast_filestream::fmt, ast_format::format, offset, and SEEK_FORCECUR.

00385 {
00386    off_t min, max, cur;
00387    long offset = 0, bytes;
00388 
00389    if (fs->fmt->format == AST_FORMAT_G722)
00390       bytes = sample_offset / 2;
00391    else
00392       bytes = sample_offset;
00393 
00394    min = AU_HEADER_SIZE;
00395    cur = ftello(fs->f);
00396    fseek(fs->f, 0, SEEK_END);
00397    max = ftello(fs->f);
00398 
00399    if (whence == SEEK_SET)
00400       offset = bytes + min;
00401    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
00402       offset = bytes + cur;
00403    else if (whence == SEEK_END)
00404       offset = max - bytes;
00405         if (whence != SEEK_FORCECUR) {
00406       offset = (offset > max) ? max : offset;
00407    }
00408 
00409    /* always protect the header space. */
00410    offset = (offset < min) ? min : offset;
00411 
00412    return fseeko(fs->f, offset, SEEK_SET);
00413 }

static off_t au_tell ( struct ast_filestream *  fs  )  [static]

Definition at line 422 of file format_pcm.c.

References AU_HEADER_SIZE, ast_filestream::f, and offset.

00423 {
00424    off_t offset = ftello(fs->f);
00425    return offset - AU_HEADER_SIZE;
00426 }

static int au_trunc ( struct ast_filestream *  fs  )  [static]

Definition at line 415 of file format_pcm.c.

References ast_filestream::f, and update_header().

00416 {
00417    if (ftruncate(fileno(fs->f), ftell(fs->f)))
00418       return -1;
00419    return update_header(fs->f);
00420 }

static int check_header ( FILE *  f  )  [static]

Definition at line 269 of file format_pcm.c.

References ast_log(), AU_ENC_8BIT_ULAW, AU_HDR_CHANNELS_OFF, AU_HDR_ENCODING_OFF, AU_HDR_HDR_SIZE_OFF, AU_HDR_MAGIC_OFF, AU_HDR_SAMPLE_RATE_OFF, AU_HEADER, AU_HEADER_SIZE, AU_MAGIC, channels, DEFAULT_SAMPLE_RATE, LOG_WARNING, and ltohl.

Referenced by au_open(), and wav_open().

00270 {
00271    AU_HEADER(header);
00272    uint32_t magic;
00273    uint32_t hdr_size;
00274    uint32_t data_size;
00275    uint32_t encoding;
00276    uint32_t sample_rate;
00277    uint32_t channels;
00278 
00279    if (fread(header, 1, AU_HEADER_SIZE, f) != AU_HEADER_SIZE) {
00280       ast_log(LOG_WARNING, "Read failed (header)\n");
00281       return -1;
00282    }
00283    magic = ltohl(header[AU_HDR_MAGIC_OFF]);
00284    if (magic != (uint32_t) AU_MAGIC) {
00285       ast_log(LOG_WARNING, "Bad magic: 0x%x\n", magic);
00286    }
00287    hdr_size = ltohl(header[AU_HDR_HDR_SIZE_OFF]);
00288    if (hdr_size < AU_HEADER_SIZE) {
00289       hdr_size = AU_HEADER_SIZE;
00290    }
00291 /* data_size = ltohl(header[AU_HDR_DATA_SIZE_OFF]); */
00292    encoding = ltohl(header[AU_HDR_ENCODING_OFF]);
00293    if (encoding != AU_ENC_8BIT_ULAW) {
00294       ast_log(LOG_WARNING, "Unexpected format: %d. Only 8bit ULAW allowed (%d)\n", encoding, AU_ENC_8BIT_ULAW);
00295       return -1;
00296    }
00297    sample_rate = ltohl(header[AU_HDR_SAMPLE_RATE_OFF]);
00298    if (sample_rate != DEFAULT_SAMPLE_RATE) {
00299       ast_log(LOG_WARNING, "Sample rate can only be 8000 not %d\n", sample_rate);
00300       return -1;
00301    }
00302    channels = ltohl(header[AU_HDR_CHANNELS_OFF]);
00303    if (channels != 1) {
00304       ast_log(LOG_WARNING, "Not in mono: channels=%d\n", channels);
00305       return -1;
00306    }
00307    /* Skip to data */
00308    fseek(f, 0, SEEK_END);
00309    data_size = ftell(f) - hdr_size;
00310    if (fseek(f, hdr_size, SEEK_SET) == -1 ) {
00311       ast_log(LOG_WARNING, "Failed to skip to data: %d\n", hdr_size);
00312       return -1;
00313    }
00314    return data_size;
00315 }

static int load_module ( void   )  [static]

Definition at line 483 of file format_pcm.c.

References alaw_f, ast_format_register, AST_LIN2A, AST_LIN2MU, au_f, g722_f, and pcm_f.

00484 {
00485    int index;
00486 
00487    /* XXX better init ? */
00488    for (index = 0; index < (sizeof(ulaw_silence) / sizeof(ulaw_silence[0])); index++)
00489       ulaw_silence[index] = AST_LIN2MU(0);
00490    for (index = 0; index < (sizeof(alaw_silence) / sizeof(alaw_silence[0])); index++)
00491       alaw_silence[index] = AST_LIN2A(0);
00492 
00493    return ast_format_register(&pcm_f)
00494       || ast_format_register(&alaw_f)
00495       || ast_format_register(&au_f)
00496       || ast_format_register(&g722_f);
00497 }

static struct ast_frame* pcm_read ( struct ast_filestream *  s,
int *  whennext 
) [static]

Definition at line 89 of file format_pcm.c.

References AST_FORMAT_G722, AST_FRAME_SET_BUFFER, AST_FRAME_VOICE, AST_FRIENDLY_OFFSET, ast_log(), BUF_SIZE, errno, LOG_WARNING, and s.

00090 {
00091    int res;
00092    
00093    /* Send a frame from the file to the appropriate channel */
00094 
00095    s->fr.frametype = AST_FRAME_VOICE;
00096    s->fr.subclass = s->fmt->format;
00097    s->fr.mallocd = 0;
00098    AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, BUF_SIZE);
00099    if ((res = fread(s->fr.data, 1, s->fr.datalen, s->f)) < 1) {
00100       if (res)
00101          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00102       return NULL;
00103    }
00104    s->fr.datalen = res;
00105    if (s->fmt->format == AST_FORMAT_G722)
00106       *whennext = s->fr.samples = res * 2;
00107    else
00108       *whennext = s->fr.samples = res;
00109    return &s->fr;
00110 }

static int pcm_seek ( struct ast_filestream *  fs,
off_t  sample_offset,
int  whence 
) [static]

Definition at line 112 of file format_pcm.c.

References AST_FORMAT_ALAW, ast_log(), BUF_SIZE, ast_filestream::f, ast_filestream::fmt, ast_format::format, LOG_WARNING, offset, SEEK_FORCECUR, and ast_frame::src.

00113 {
00114    off_t cur, max, offset = 0;
00115    int ret = -1;  /* assume error */
00116 
00117    cur = ftello(fs->f);
00118    fseeko(fs->f, 0, SEEK_END);
00119    max = ftello(fs->f);
00120 
00121    switch (whence) {
00122    case SEEK_SET:
00123       offset = sample_offset;
00124       break;
00125    case SEEK_END:
00126       offset = max - sample_offset;
00127       break;
00128    case SEEK_CUR:
00129    case SEEK_FORCECUR:
00130       offset = cur + sample_offset;
00131       break;
00132    default:
00133       ast_log(LOG_WARNING, "invalid whence %d, assuming SEEK_SET\n", whence);
00134       offset = sample_offset;
00135    }
00136    if (offset < 0) {
00137       ast_log(LOG_WARNING, "negative offset %ld, resetting to 0\n", (long) offset);
00138       offset = 0;
00139    }
00140    if (whence == SEEK_FORCECUR && offset > max) { /* extend the file */
00141       size_t left = offset - max;
00142       const char *src = (fs->fmt->format == AST_FORMAT_ALAW) ? alaw_silence : ulaw_silence;
00143 
00144       while (left) {
00145          size_t written = fwrite(src, 1, (left > BUF_SIZE) ? BUF_SIZE : left, fs->f);
00146          if (written == -1)
00147             break;   /* error */
00148          left -= written;
00149       }
00150       ret = 0; /* successful */
00151    } else {
00152       if (offset > max) {
00153          ast_log(LOG_WARNING, "offset too large %ld, truncating to %ld\n", (long) offset, (long) max);
00154          offset = max;
00155       }
00156       ret = fseeko(fs->f, offset, SEEK_SET);
00157    }
00158    return ret;
00159 }

static off_t pcm_tell ( struct ast_filestream *  fs  )  [static]

Definition at line 166 of file format_pcm.c.

References ast_filestream::f.

00167 {
00168    return ftello(fs->f);
00169 }

static int pcm_trunc ( struct ast_filestream *  fs  )  [static]

Definition at line 161 of file format_pcm.c.

References ast_filestream::f.

00162 {
00163    return ftruncate(fileno(fs->f), ftello(fs->f));
00164 }

static int pcm_write ( struct ast_filestream *  fs,
struct ast_frame *  f 
) [static]

Definition at line 171 of file format_pcm.c.

References ast_filestream::_private, AST_FORMAT_ALAW, AST_FRAME_VOICE, ast_log(), errno, ast_filestream::f, f, ast_filestream::fmt, ast_format::format, LOG_WARNING, and s.

00172 {
00173    int res;
00174 
00175    if (f->frametype != AST_FRAME_VOICE) {
00176       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
00177       return -1;
00178    }
00179    if (f->subclass != fs->fmt->format) {
00180       ast_log(LOG_WARNING, "Asked to write incompatible format frame (%d)!\n", f->subclass);
00181       return -1;
00182    }
00183 
00184 #ifdef REALTIME_WRITE
00185    if (s->fmt->format == AST_FORMAT_ALAW) {
00186       struct pcm_desc *pd = (struct pcm_desc *)fs->_private;
00187       struct stat stat_buf;
00188       unsigned long cur_time = get_time();
00189       unsigned long fpos = ( cur_time - pd->start_time ) * 8;  /* 8 bytes per msec */
00190       /* Check if we have written to this position yet. If we have, then increment pos by one frame
00191       *  for some degree of protection against receiving packets in the same clock tick.
00192       */
00193       
00194       fstat(fileno(fs->f), &stat_buf );
00195       if (stat_buf.st_size > fpos )
00196          fpos += f->datalen;  /* Incrementing with the size of this current frame */
00197 
00198       if (stat_buf.st_size < fpos) {
00199          /* fill the gap with 0x55 rather than 0. */
00200          char buf[1024];
00201          unsigned long cur, to_write;
00202 
00203          cur = stat_buf.st_size;
00204          if (fseek(fs->f, cur, SEEK_SET) < 0) {
00205             ast_log( LOG_WARNING, "Cannot seek in file: %s\n", strerror(errno) );
00206             return -1;
00207          }
00208          memset(buf, 0x55, 512);
00209          while (cur < fpos) {
00210             to_write = fpos - cur;
00211             if (to_write > sizeof(buf))
00212                to_write = sizeof(buf);
00213             fwrite(buf, 1, to_write, fs->f);
00214             cur += to_write;
00215          }
00216       }
00217 
00218       if (fseek(s->f, fpos, SEEK_SET) < 0) {
00219          ast_log( LOG_WARNING, "Cannot seek in file: %s\n", strerror(errno) );
00220          return -1;
00221       }
00222    }
00223 #endif   /* REALTIME_WRITE */
00224    
00225    if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
00226       ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
00227       return -1;
00228    }
00229    return 0;
00230 }

static int unload_module ( void   )  [static]

Definition at line 499 of file format_pcm.c.

References alaw_f, ast_format_unregister(), au_f, g722_f, ast_format::name, and pcm_f.

00500 {
00501    return ast_format_unregister(pcm_f.name)
00502       || ast_format_unregister(alaw_f.name)
00503       || ast_format_unregister(au_f.name)
00504       || ast_format_unregister(g722_f.name);
00505 }

static int update_header ( FILE *  f  )  [static]

Definition at line 317 of file format_pcm.c.

References ast_log(), AU_HDR_DATA_SIZE_OFF, AU_HEADER_SIZE, htoll, and LOG_WARNING.

Referenced by au_trunc(), wav_trunc(), and wav_write().

00318 {
00319    off_t cur, end;
00320    uint32_t datalen;
00321    int bytes;
00322 
00323    cur = ftell(f);
00324    fseek(f, 0, SEEK_END);
00325    end = ftell(f);
00326    /* data starts 24 bytes in */
00327    bytes = end - AU_HEADER_SIZE;
00328    datalen = htoll(bytes);
00329 
00330    if (cur < 0) {
00331       ast_log(LOG_WARNING, "Unable to find our position\n");
00332       return -1;
00333    }
00334    if (fseek(f, AU_HDR_DATA_SIZE_OFF * sizeof(uint32_t), SEEK_SET)) {
00335       ast_log(LOG_WARNING, "Unable to set our position\n");
00336       return -1;
00337    }
00338    if (fwrite(&datalen, 1, sizeof(datalen), f) != sizeof(datalen)) {
00339       ast_log(LOG_WARNING, "Unable to set write file size\n");
00340       return -1;
00341    }
00342    if (fseek(f, cur, SEEK_SET)) {
00343       ast_log(LOG_WARNING, "Unable to return to position\n");
00344       return -1;
00345    }
00346    return 0;
00347 }

static int write_header ( FILE *  f  )  [static]

Definition at line 349 of file format_pcm.c.

References ast_log(), AU_ENC_8BIT_ULAW, AU_HDR_CHANNELS_OFF, AU_HDR_DATA_SIZE_OFF, AU_HDR_ENCODING_OFF, AU_HDR_HDR_SIZE_OFF, AU_HDR_MAGIC_OFF, AU_HDR_SAMPLE_RATE_OFF, AU_HEADER, AU_HEADER_SIZE, AU_MAGIC, DEFAULT_SAMPLE_RATE, htoll, and LOG_WARNING.

Referenced by au_rewrite(), and wav_rewrite().

00350 {
00351    AU_HEADER(header);
00352 
00353    header[AU_HDR_MAGIC_OFF] = htoll((uint32_t) AU_MAGIC);
00354    header[AU_HDR_HDR_SIZE_OFF] = htoll(AU_HEADER_SIZE);
00355    header[AU_HDR_DATA_SIZE_OFF] = 0;
00356    header[AU_HDR_ENCODING_OFF] = htoll(AU_ENC_8BIT_ULAW);
00357    header[AU_HDR_SAMPLE_RATE_OFF] = htoll(DEFAULT_SAMPLE_RATE);
00358    header[AU_HDR_CHANNELS_OFF] = htoll(1);
00359 
00360    /* Write an au header, ignoring sizes which will be filled in later */
00361    fseek(f, 0, SEEK_SET);
00362    if (fwrite(header, 1, AU_HEADER_SIZE, f) != AU_HEADER_SIZE) {
00363       ast_log(LOG_WARNING, "Unable to write header\n");
00364       return -1;
00365    }
00366    return 0;
00367 }

Variable Documentation

struct ast_format alaw_f [static]

Definition at line 428 of file format_pcm.c.

Referenced by load_module(), and unload_module().

char alaw_silence[BUF_SIZE] [static]

Definition at line 53 of file format_pcm.c.

struct ast_format au_f [static]

Definition at line 469 of file format_pcm.c.

Referenced by load_module(), and unload_module().

struct ast_format g722_f [static]

Definition at line 457 of file format_pcm.c.

Referenced by load_module(), and unload_module().

struct ast_format pcm_f [static]

Definition at line 445 of file format_pcm.c.

Referenced by load_module(), and unload_module().

char ulaw_silence[BUF_SIZE] [static]

Definition at line 52 of file format_pcm.c.

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