Wed Aug 15 01:25:09 2007

Asterisk developer's documentation


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_framepcm_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 241 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_CHANNELS_OFF   5

Definition at line 239 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_DATA_SIZE_OFF   2

Definition at line 236 of file format_pcm.c.

Referenced by update_header(), and write_header().

#define AU_HDR_ENCODING_OFF   3

Definition at line 237 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_HDR_SIZE_OFF   1

Definition at line 235 of file format_pcm.c.

Referenced by write_header().

#define AU_HDR_MAGIC_OFF   0

Definition at line 234 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HDR_SAMPLE_RATE_OFF   4

Definition at line 238 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HEADER ( var   )     uint32_t var[6]

Definition at line 232 of file format_pcm.c.

Referenced by check_header(), and write_header().

#define AU_HEADER_SIZE   24

Definition at line 231 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 243 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)

Definition at line 245 of file format_pcm.c.

Referenced by update_header(), and write_header().

#define htols (  )     (b)

Definition at line 246 of file format_pcm.c.

Referenced by write_header().

#define ltohl (  )     (b)

Definition at line 247 of file format_pcm.c.

Referenced by check_header().

#define ltohs (  )     (b)

Definition at line 248 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 365 of file format_pcm.c.

References check_header(), and ast_filestream::f.

00366 {
00367    if (check_header(s->f) < 0)
00368       return -1;
00369    return 0;
00370 }

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

Definition at line 372 of file format_pcm.c.

References ast_filestream::f, and write_header().

00373 {
00374    if (write_header(s->f))
00375       return -1;
00376    return 0;
00377 }

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

Definition at line 380 of file format_pcm.c.

References AU_HEADER_SIZE, ast_filestream::f, offset, and SEEK_FORCECUR.

00381 {
00382    off_t min, max, cur;
00383    long offset = 0, samples;
00384    
00385    samples = sample_offset;
00386    min = AU_HEADER_SIZE;
00387    cur = ftello(fs->f);
00388    fseek(fs->f, 0, SEEK_END);
00389    max = ftello(fs->f);
00390    if (whence == SEEK_SET)
00391       offset = samples + min;
00392    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
00393       offset = samples + cur;
00394    else if (whence == SEEK_END)
00395       offset = max - samples;
00396         if (whence != SEEK_FORCECUR) {
00397       offset = (offset > max) ? max : offset;
00398    }
00399    /* always protect the header space. */
00400    offset = (offset < min) ? min : offset;
00401    return fseeko(fs->f, offset, SEEK_SET);
00402 }

static off_t au_tell ( struct ast_filestream fs  )  [static]

Definition at line 411 of file format_pcm.c.

References AU_HEADER_SIZE, ast_filestream::f, and offset.

00412 {
00413    off_t offset = ftello(fs->f);
00414    return offset - AU_HEADER_SIZE;
00415 }

static int au_trunc ( struct ast_filestream fs  )  [static]

Definition at line 404 of file format_pcm.c.

References ast_filestream::f, and update_header().

00405 {
00406    if (ftruncate(fileno(fs->f), ftell(fs->f)))
00407       return -1;
00408    return update_header(fs->f);
00409 }

static int check_header ( FILE *  f  )  [static]

Definition at line 266 of file format_pcm.c.

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

Referenced by au_open(), and wav_open().

00267 {
00268    AU_HEADER(header);
00269    uint32_t magic;
00270    uint32_t hdr_size;
00271    uint32_t data_size;
00272    uint32_t encoding;
00273    uint32_t sample_rate;
00274    uint32_t channels;
00275 
00276    if (fread(header, 1, AU_HEADER_SIZE, f) != AU_HEADER_SIZE) {
00277       ast_log(LOG_WARNING, "Read failed (header)\n");
00278       return -1;
00279    }
00280    magic = ltohl(header[AU_HDR_MAGIC_OFF]);
00281    if (magic != (uint32_t) AU_MAGIC) {
00282       ast_log(LOG_WARNING, "Bad magic: 0x%x\n", magic);
00283    }
00284 /* hdr_size = ltohl(header[AU_HDR_HDR_SIZE_OFF]);
00285    if (hdr_size < AU_HEADER_SIZE)*/
00286    hdr_size = AU_HEADER_SIZE;
00287 /* data_size = ltohl(header[AU_HDR_DATA_SIZE_OFF]); */
00288    encoding = ltohl(header[AU_HDR_ENCODING_OFF]);
00289    if (encoding != AU_ENC_8BIT_ULAW) {
00290       ast_log(LOG_WARNING, "Unexpected format: %d. Only 8bit ULAW allowed (%d)\n", encoding, AU_ENC_8BIT_ULAW);
00291       return -1;
00292    }
00293    sample_rate = ltohl(header[AU_HDR_SAMPLE_RATE_OFF]);
00294    if (sample_rate != DEFAULT_SAMPLE_RATE) {
00295       ast_log(LOG_WARNING, "Sample rate can only be 8000 not %d\n", sample_rate);
00296       return -1;
00297    }
00298    channels = ltohl(header[AU_HDR_CHANNELS_OFF]);
00299    if (channels != 1) {
00300       ast_log(LOG_WARNING, "Not in mono: channels=%d\n", channels);
00301       return -1;
00302    }
00303    /* Skip to data */
00304    fseek(f, 0, SEEK_END);
00305    data_size = ftell(f) - hdr_size;
00306    if (fseek(f, hdr_size, SEEK_SET) == -1 ) {
00307       ast_log(LOG_WARNING, "Failed to skip to data: %d\n", hdr_size);
00308       return -1;
00309    }
00310    return data_size;
00311 }

static int load_module ( void   )  [static]

Definition at line 472 of file format_pcm.c.

References ast_format_register, AST_LIN2A, and AST_LIN2MU.

00473 {
00474    int index;
00475 
00476    /* XXX better init ? */
00477    for (index = 0; index < (sizeof(ulaw_silence) / sizeof(ulaw_silence[0])); index++)
00478       ulaw_silence[index] = AST_LIN2MU(0);
00479    for (index = 0; index < (sizeof(alaw_silence) / sizeof(alaw_silence[0])); index++)
00480       alaw_silence[index] = AST_LIN2A(0);
00481 
00482    return ast_format_register(&pcm_f)
00483       || ast_format_register(&alaw_f)
00484       || ast_format_register(&au_f)
00485       || ast_format_register(&g722_f);
00486 }

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

Definition at line 89 of file format_pcm.c.

References AST_FRAME_SET_BUFFER, AST_FRAME_VOICE, AST_FRIENDLY_OFFSET, ast_log(), ast_filestream::buf, BUF_SIZE, ast_frame::data, ast_frame::datalen, ast_filestream::f, ast_filestream::fmt, ast_format::format, ast_filestream::fr, ast_frame::frametype, LOG_WARNING, ast_frame::mallocd, ast_frame::samples, and ast_frame::subclass.

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    *whennext = s->fr.samples = res;
00106    return &s->fr;
00107 }

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

Definition at line 109 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.

00110 {
00111    off_t cur, max, offset = 0;
00112    int ret = -1;  /* assume error */
00113 
00114    cur = ftello(fs->f);
00115    fseeko(fs->f, 0, SEEK_END);
00116    max = ftello(fs->f);
00117 
00118    switch (whence) {
00119    case SEEK_SET:
00120       offset = sample_offset;
00121       break;
00122    case SEEK_END:
00123       offset = max - sample_offset;
00124       break;
00125    case SEEK_CUR:
00126    case SEEK_FORCECUR:
00127       offset = cur + sample_offset;
00128       break;
00129    default:
00130       ast_log(LOG_WARNING, "invalid whence %d, assuming SEEK_SET\n", whence);
00131       offset = sample_offset;
00132    }
00133    if (offset < 0) {
00134       ast_log(LOG_WARNING, "negative offset %ld, resetting to 0\n", (long) offset);
00135       offset = 0;
00136    }
00137    if (whence == SEEK_FORCECUR && offset > max) { /* extend the file */
00138       size_t left = offset - max;
00139       const char *src = (fs->fmt->format == AST_FORMAT_ALAW) ? alaw_silence : ulaw_silence;
00140 
00141       while (left) {
00142          size_t written = fwrite(src, 1, (left > BUF_SIZE) ? BUF_SIZE : left, fs->f);
00143          if (written == -1)
00144             break;   /* error */
00145          left -= written;
00146       }
00147       ret = 0; /* successful */
00148    } else {
00149       if (offset > max) {
00150          ast_log(LOG_WARNING, "offset too large %ld, truncating to %ld\n", (long) offset, (long) max);
00151          offset = max;
00152       }
00153       ret = fseeko(fs->f, offset, SEEK_SET);
00154    }
00155    return ret;
00156 }

static off_t pcm_tell ( struct ast_filestream fs  )  [static]

Definition at line 163 of file format_pcm.c.

References ast_filestream::f.

00164 {
00165    return ftello(fs->f);
00166 }

static int pcm_trunc ( struct ast_filestream fs  )  [static]

Definition at line 158 of file format_pcm.c.

References ast_filestream::f.

00159 {
00160    return ftruncate(fileno(fs->f), ftello(fs->f));
00161 }

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

Definition at line 168 of file format_pcm.c.

References AST_FORMAT_ALAW, AST_FRAME_VOICE, ast_log(), ast_frame::data, ast_frame::datalen, ast_filestream::f, ast_filestream::fmt, ast_format::format, ast_frame::frametype, LOG_WARNING, ast_filestream::private, and ast_frame::subclass.

00169 {
00170    int res;
00171 
00172    if (f->frametype != AST_FRAME_VOICE) {
00173       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
00174       return -1;
00175    }
00176    if (f->subclass != fs->fmt->format) {
00177       ast_log(LOG_WARNING, "Asked to write incompatible format frame (%d)!\n", f->subclass);
00178       return -1;
00179    }
00180 
00181 #ifdef REALTIME_WRITE
00182    if (s->fmt->format == AST_FORMAT_ALAW) {
00183       struct pcm_desc *pd = (struct pcm_desc *)fs->private;
00184       struct stat stat_buf;
00185       unsigned long cur_time = get_time();
00186       unsigned long fpos = ( cur_time - pd->start_time ) * 8;  /* 8 bytes per msec */
00187       /* Check if we have written to this position yet. If we have, then increment pos by one frame
00188       *  for some degree of protection against receiving packets in the same clock tick.
00189       */
00190       
00191       fstat(fileno(fs->f), &stat_buf );
00192       if (stat_buf.st_size > fpos )
00193          fpos += f->datalen;  /* Incrementing with the size of this current frame */
00194 
00195       if (stat_buf.st_size < fpos) {
00196          /* fill the gap with 0x55 rather than 0. */
00197          char buf[1024];
00198          unsigned long cur, to_write;
00199 
00200          cur = stat_buf.st_size;
00201          if (fseek(fs->f, cur, SEEK_SET) < 0) {
00202             ast_log( LOG_WARNING, "Cannot seek in file: %s\n", strerror(errno) );
00203             return -1;
00204          }
00205          memset(buf, 0x55, 512);
00206          while (cur < fpos) {
00207             to_write = fpos - cur;
00208             if (to_write > sizeof(buf))
00209                to_write = sizeof(buf);
00210             fwrite(buf, 1, to_write, fs->f);
00211             cur += to_write;
00212          }
00213       }
00214 
00215       if (fseek(s->f, fpos, SEEK_SET) < 0) {
00216          ast_log( LOG_WARNING, "Cannot seek in file: %s\n", strerror(errno) );
00217          return -1;
00218       }
00219    }
00220 #endif   /* REALTIME_WRITE */
00221    
00222    if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
00223       ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
00224       return -1;
00225    }
00226    return 0;
00227 }

static int unload_module ( void   )  [static]

Definition at line 488 of file format_pcm.c.

References ast_format_unregister(), and ast_format::name.

static int update_header ( FILE *  f  )  [static]

Definition at line 313 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().

00314 {
00315    off_t cur, end;
00316    uint32_t datalen;
00317    int bytes;
00318 
00319    cur = ftell(f);
00320    fseek(f, 0, SEEK_END);
00321    end = ftell(f);
00322    /* data starts 24 bytes in */
00323    bytes = end - AU_HEADER_SIZE;
00324    datalen = htoll(bytes);
00325 
00326    if (cur < 0) {
00327       ast_log(LOG_WARNING, "Unable to find our position\n");
00328       return -1;
00329    }
00330    if (fseek(f, AU_HDR_DATA_SIZE_OFF * sizeof(uint32_t), SEEK_SET)) {
00331       ast_log(LOG_WARNING, "Unable to set our position\n");
00332       return -1;
00333    }
00334    if (fwrite(&datalen, 1, sizeof(datalen), f) != sizeof(datalen)) {
00335       ast_log(LOG_WARNING, "Unable to set write file size\n");
00336       return -1;
00337    }
00338    if (fseek(f, cur, SEEK_SET)) {
00339       ast_log(LOG_WARNING, "Unable to return to position\n");
00340       return -1;
00341    }
00342    return 0;
00343 }

static int write_header ( FILE *  f  )  [static]

Definition at line 345 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().

00346 {
00347    AU_HEADER(header);
00348 
00349    header[AU_HDR_MAGIC_OFF] = htoll((uint32_t) AU_MAGIC);
00350    header[AU_HDR_HDR_SIZE_OFF] = htoll(AU_HEADER_SIZE);
00351    header[AU_HDR_DATA_SIZE_OFF] = 0;
00352    header[AU_HDR_ENCODING_OFF] = htoll(AU_ENC_8BIT_ULAW);
00353    header[AU_HDR_SAMPLE_RATE_OFF] = htoll(DEFAULT_SAMPLE_RATE);
00354    header[AU_HDR_CHANNELS_OFF] = htoll(1);
00355 
00356    /* Write an au header, ignoring sizes which will be filled in later */
00357    fseek(f, 0, SEEK_SET);
00358    if (fwrite(header, 1, AU_HEADER_SIZE, f) != AU_HEADER_SIZE) {
00359       ast_log(LOG_WARNING, "Unable to write header\n");
00360       return -1;
00361    }
00362    return 0;
00363 }


Variable Documentation

struct ast_format alaw_f [static]

Definition at line 417 of file format_pcm.c.

char alaw_silence[BUF_SIZE] [static]

Definition at line 53 of file format_pcm.c.

struct ast_format au_f [static]

Definition at line 458 of file format_pcm.c.

struct ast_format g722_f [static]

Definition at line 446 of file format_pcm.c.

struct ast_format pcm_f [static]

Definition at line 434 of file format_pcm.c.

char ulaw_silence[BUF_SIZE] [static]

Definition at line 52 of file format_pcm.c.


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