Wed Oct 28 11:51:04 2009

Asterisk developer's documentation


format_wav.c

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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 Work with WAV in the proprietary Microsoft format.
00022  * Microsoft WAV format (8000hz Signed Linear)
00023  * \arg File name extension: wav (lower case)
00024  * \ingroup formats
00025  */
00026  
00027 #include "asterisk.h"
00028 
00029 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 186844 $")
00030 
00031 #include "asterisk/mod_format.h"
00032 #include "asterisk/module.h"
00033 #include "asterisk/endian.h"
00034 
00035 /* Some Ideas for this code came from makewave.c by Jeffrey Chilton */
00036 
00037 /* Portions of the conversion code are by guido@sienanet.it */
00038 
00039 #define  WAV_BUF_SIZE   320
00040 
00041 struct wav_desc { /* format-specific parameters */
00042    int bytes;
00043    int lasttimeout;
00044    int maxlen;
00045    struct timeval last;
00046 };
00047 
00048 #define BLOCKSIZE 160
00049 
00050 #if __BYTE_ORDER == __LITTLE_ENDIAN
00051 #define htoll(b) (b)
00052 #define htols(b) (b)
00053 #define ltohl(b) (b)
00054 #define ltohs(b) (b)
00055 #else
00056 #if __BYTE_ORDER == __BIG_ENDIAN
00057 #define htoll(b)  \
00058           (((((b)      ) & 0xFF) << 24) | \
00059           ((((b) >>  8) & 0xFF) << 16) | \
00060          ((((b) >> 16) & 0xFF) <<  8) | \
00061          ((((b) >> 24) & 0xFF)      ))
00062 #define htols(b) \
00063           (((((b)      ) & 0xFF) << 8) | \
00064          ((((b) >> 8) & 0xFF)      ))
00065 #define ltohl(b) htoll(b)
00066 #define ltohs(b) htols(b)
00067 #else
00068 #error "Endianess not defined"
00069 #endif
00070 #endif
00071 
00072 
00073 static int check_header(FILE *f)
00074 {
00075    int type, size, formtype;
00076    int fmt, hsize;
00077    short format, chans, bysam, bisam;
00078    int bysec;
00079    int freq;
00080    int data;
00081    if (fread(&type, 1, 4, f) != 4) {
00082       ast_log(LOG_WARNING, "Read failed (type)\n");
00083       return -1;
00084    }
00085    if (fread(&size, 1, 4, f) != 4) {
00086       ast_log(LOG_WARNING, "Read failed (size)\n");
00087       return -1;
00088    }
00089    size = ltohl(size);
00090    if (fread(&formtype, 1, 4, f) != 4) {
00091       ast_log(LOG_WARNING, "Read failed (formtype)\n");
00092       return -1;
00093    }
00094    if (memcmp(&type, "RIFF", 4)) {
00095       ast_log(LOG_WARNING, "Does not begin with RIFF\n");
00096       return -1;
00097    }
00098    if (memcmp(&formtype, "WAVE", 4)) {
00099       ast_log(LOG_WARNING, "Does not contain WAVE\n");
00100       return -1;
00101    }
00102    if (fread(&fmt, 1, 4, f) != 4) {
00103       ast_log(LOG_WARNING, "Read failed (fmt)\n");
00104       return -1;
00105    }
00106    if (memcmp(&fmt, "fmt ", 4)) {
00107       ast_log(LOG_WARNING, "Does not say fmt\n");
00108       return -1;
00109    }
00110    if (fread(&hsize, 1, 4, f) != 4) {
00111       ast_log(LOG_WARNING, "Read failed (formtype)\n");
00112       return -1;
00113    }
00114    if (ltohl(hsize) < 16) {
00115       ast_log(LOG_WARNING, "Unexpected header size %d\n", ltohl(hsize));
00116       return -1;
00117    }
00118    if (fread(&format, 1, 2, f) != 2) {
00119       ast_log(LOG_WARNING, "Read failed (format)\n");
00120       return -1;
00121    }
00122    if (ltohs(format) != 1) {
00123       ast_log(LOG_WARNING, "Not a wav file %d\n", ltohs(format));
00124       return -1;
00125    }
00126    if (fread(&chans, 1, 2, f) != 2) {
00127       ast_log(LOG_WARNING, "Read failed (format)\n");
00128       return -1;
00129    }
00130    if (ltohs(chans) != 1) {
00131       ast_log(LOG_WARNING, "Not in mono %d\n", ltohs(chans));
00132       return -1;
00133    }
00134    if (fread(&freq, 1, 4, f) != 4) {
00135       ast_log(LOG_WARNING, "Read failed (freq)\n");
00136       return -1;
00137    }
00138    if (ltohl(freq) != DEFAULT_SAMPLE_RATE) {
00139       ast_log(LOG_WARNING, "Unexpected frequency %d\n", ltohl(freq));
00140       return -1;
00141    }
00142    /* Ignore the byte frequency */
00143    if (fread(&bysec, 1, 4, f) != 4) {
00144       ast_log(LOG_WARNING, "Read failed (BYTES_PER_SECOND)\n");
00145       return -1;
00146    }
00147    /* Check bytes per sample */
00148    if (fread(&bysam, 1, 2, f) != 2) {
00149       ast_log(LOG_WARNING, "Read failed (BYTES_PER_SAMPLE)\n");
00150       return -1;
00151    }
00152    if (ltohs(bysam) != 2) {
00153       ast_log(LOG_WARNING, "Can only handle 16bits per sample: %d\n", ltohs(bysam));
00154       return -1;
00155    }
00156    if (fread(&bisam, 1, 2, f) != 2) {
00157       ast_log(LOG_WARNING, "Read failed (Bits Per Sample): %d\n", ltohs(bisam));
00158       return -1;
00159    }
00160    /* Skip any additional header */
00161    if (fseek(f,ltohl(hsize)-16,SEEK_CUR) == -1 ) {
00162       ast_log(LOG_WARNING, "Failed to skip remaining header bytes: %d\n", ltohl(hsize)-16 );
00163       return -1;
00164    }
00165    /* Skip any facts and get the first data block */
00166    for(;;)
00167    { 
00168       char buf[4];
00169        
00170        /* Begin data chunk */
00171        if (fread(&buf, 1, 4, f) != 4) {
00172          ast_log(LOG_WARNING, "Read failed (data)\n");
00173          return -1;
00174        }
00175        /* Data has the actual length of data in it */
00176        if (fread(&data, 1, 4, f) != 4) {
00177          ast_log(LOG_WARNING, "Read failed (data)\n");
00178          return -1;
00179        }
00180        data = ltohl(data);
00181        if(memcmp(buf, "data", 4) == 0 ) 
00182          break;
00183        if(memcmp(buf, "fact", 4) != 0 ) {
00184          ast_log(LOG_WARNING, "Unknown block - not fact or data\n");
00185          return -1;
00186        }
00187        if (fseek(f,data,SEEK_CUR) == -1 ) {
00188          ast_log(LOG_WARNING, "Failed to skip fact block: %d\n", data );
00189          return -1;
00190        }
00191    }
00192 #if 0
00193    curpos = lseek(fd, 0, SEEK_CUR);
00194    truelength = lseek(fd, 0, SEEK_END);
00195    lseek(fd, curpos, SEEK_SET);
00196    truelength -= curpos;
00197 #endif   
00198    return data;
00199 }
00200 
00201 static int update_header(FILE *f)
00202 {
00203    off_t cur,end;
00204    int datalen,filelen,bytes;
00205    
00206    cur = ftello(f);
00207    fseek(f, 0, SEEK_END);
00208    end = ftello(f);
00209    /* data starts 44 bytes in */
00210    bytes = end - 44;
00211    datalen = htoll(bytes);
00212    /* chunk size is bytes of data plus 36 bytes of header */
00213    filelen = htoll(36 + bytes);
00214    
00215    if (cur < 0) {
00216       ast_log(LOG_WARNING, "Unable to find our position\n");
00217       return -1;
00218    }
00219    if (fseek(f, 4, SEEK_SET)) {
00220       ast_log(LOG_WARNING, "Unable to set our position\n");
00221       return -1;
00222    }
00223    if (fwrite(&filelen, 1, 4, f) != 4) {
00224       ast_log(LOG_WARNING, "Unable to set write file size\n");
00225       return -1;
00226    }
00227    if (fseek(f, 40, SEEK_SET)) {
00228       ast_log(LOG_WARNING, "Unable to set our position\n");
00229       return -1;
00230    }
00231    if (fwrite(&datalen, 1, 4, f) != 4) {
00232       ast_log(LOG_WARNING, "Unable to set write datalen\n");
00233       return -1;
00234    }
00235    if (fseeko(f, cur, SEEK_SET)) {
00236       ast_log(LOG_WARNING, "Unable to return to position\n");
00237       return -1;
00238    }
00239    return 0;
00240 }
00241 
00242 static int write_header(FILE *f)
00243 {
00244    unsigned int hz=htoll(8000);
00245    unsigned int bhz = htoll(16000);
00246    unsigned int hs = htoll(16);
00247    unsigned short fmt = htols(1);
00248    unsigned short chans = htols(1);
00249    unsigned short bysam = htols(2);
00250    unsigned short bisam = htols(16);
00251    unsigned int size = htoll(0);
00252    /* Write a wav header, ignoring sizes which will be filled in later */
00253    fseek(f,0,SEEK_SET);
00254    if (fwrite("RIFF", 1, 4, f) != 4) {
00255       ast_log(LOG_WARNING, "Unable to write header\n");
00256       return -1;
00257    }
00258    if (fwrite(&size, 1, 4, f) != 4) {
00259       ast_log(LOG_WARNING, "Unable to write header\n");
00260       return -1;
00261    }
00262    if (fwrite("WAVEfmt ", 1, 8, f) != 8) {
00263       ast_log(LOG_WARNING, "Unable to write header\n");
00264       return -1;
00265    }
00266    if (fwrite(&hs, 1, 4, f) != 4) {
00267       ast_log(LOG_WARNING, "Unable to write header\n");
00268       return -1;
00269    }
00270    if (fwrite(&fmt, 1, 2, f) != 2) {
00271       ast_log(LOG_WARNING, "Unable to write header\n");
00272       return -1;
00273    }
00274    if (fwrite(&chans, 1, 2, f) != 2) {
00275       ast_log(LOG_WARNING, "Unable to write header\n");
00276       return -1;
00277    }
00278    if (fwrite(&hz, 1, 4, f) != 4) {
00279       ast_log(LOG_WARNING, "Unable to write header\n");
00280       return -1;
00281    }
00282    if (fwrite(&bhz, 1, 4, f) != 4) {
00283       ast_log(LOG_WARNING, "Unable to write header\n");
00284       return -1;
00285    }
00286    if (fwrite(&bysam, 1, 2, f) != 2) {
00287       ast_log(LOG_WARNING, "Unable to write header\n");
00288       return -1;
00289    }
00290    if (fwrite(&bisam, 1, 2, f) != 2) {
00291       ast_log(LOG_WARNING, "Unable to write header\n");
00292       return -1;
00293    }
00294    if (fwrite("data", 1, 4, f) != 4) {
00295       ast_log(LOG_WARNING, "Unable to write header\n");
00296       return -1;
00297    }
00298    if (fwrite(&size, 1, 4, f) != 4) {
00299       ast_log(LOG_WARNING, "Unable to write header\n");
00300       return -1;
00301    }
00302    return 0;
00303 }
00304 
00305 static int wav_open(struct ast_filestream *s)
00306 {
00307    /* We don't have any header to read or anything really, but
00308       if we did, it would go here.  We also might want to check
00309       and be sure it's a valid file.  */
00310    struct wav_desc *tmp = (struct wav_desc *)s->_private;
00311    if ((tmp->maxlen = check_header(s->f)) < 0)
00312       return -1;
00313    return 0;
00314 }
00315 
00316 static int wav_rewrite(struct ast_filestream *s, const char *comment)
00317 {
00318    /* We don't have any header to read or anything really, but
00319       if we did, it would go here.  We also might want to check
00320       and be sure it's a valid file.  */
00321 
00322    if (write_header(s->f))
00323       return -1;
00324    return 0;
00325 }
00326 
00327 static void wav_close(struct ast_filestream *s)
00328 {
00329    char zero = 0;
00330    struct wav_desc *fs = (struct wav_desc *)s->_private;
00331 
00332    if (s->filename) {
00333       update_header(s->f);
00334    }
00335 
00336    /* Pad to even length */
00337    if (fs->bytes & 0x1) {
00338       if (!fwrite(&zero, 1, 1, s->f)) {
00339          ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
00340       }
00341    }
00342 }
00343 
00344 static struct ast_frame *wav_read(struct ast_filestream *s, int *whennext)
00345 {
00346    int res;
00347    int samples;   /* actual samples read */
00348 #if __BYTE_ORDER == __BIG_ENDIAN
00349    int x;
00350 #endif
00351    short *tmp;
00352    int bytes = WAV_BUF_SIZE;  /* in bytes */
00353    off_t here;
00354    /* Send a frame from the file to the appropriate channel */
00355    struct wav_desc *fs = (struct wav_desc *)s->_private;
00356 
00357    here = ftello(s->f);
00358    if (fs->maxlen - here < bytes)      /* truncate if necessary */
00359       bytes = fs->maxlen - here;
00360    if (bytes < 0)
00361       bytes = 0;
00362 /*    ast_debug(1, "here: %d, maxlen: %d, bytes: %d\n", here, s->maxlen, bytes); */
00363    s->fr.frametype = AST_FRAME_VOICE;
00364    s->fr.subclass = AST_FORMAT_SLINEAR;
00365    s->fr.mallocd = 0;
00366    AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, bytes);
00367    
00368    if ( (res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) <= 0 ) {
00369       if (res)
00370          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00371       return NULL;
00372    }
00373    s->fr.datalen = res;
00374    s->fr.samples = samples = res / 2;
00375 
00376    tmp = (short *)(s->fr.data.ptr);
00377 #if __BYTE_ORDER == __BIG_ENDIAN
00378    /* file format is little endian so we need to swap */
00379    for( x = 0; x < samples; x++)
00380       tmp[x] = (tmp[x] << 8) | ((tmp[x] & 0xff00) >> 8);
00381 #endif
00382 
00383    *whennext = samples;
00384    return &s->fr;
00385 }
00386 
00387 static int wav_write(struct ast_filestream *fs, struct ast_frame *f)
00388 {
00389 #if __BYTE_ORDER == __BIG_ENDIAN
00390    int x;
00391    short tmp[8000], *tmpi;
00392 #endif
00393    struct wav_desc *s = (struct wav_desc *)fs->_private;
00394    int res;
00395 
00396    if (f->frametype != AST_FRAME_VOICE) {
00397       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
00398       return -1;
00399    }
00400    if (f->subclass != AST_FORMAT_SLINEAR) {
00401       ast_log(LOG_WARNING, "Asked to write non-SLINEAR frame (%d)!\n", f->subclass);
00402       return -1;
00403    }
00404    if (!f->datalen)
00405       return -1;
00406 
00407 #if __BYTE_ORDER == __BIG_ENDIAN
00408    /* swap and write */
00409    if (f->datalen > sizeof(tmp)) {
00410       ast_log(LOG_WARNING, "Data length is too long\n");
00411       return -1;
00412    }
00413    tmpi = f->data.ptr;
00414    for (x=0; x < f->datalen/2; x++) 
00415       tmp[x] = (tmpi[x] << 8) | ((tmpi[x] & 0xff00) >> 8);
00416 
00417    if ((res = fwrite(tmp, 1, f->datalen, fs->f)) != f->datalen ) {
00418 #else
00419    /* just write */
00420    if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen ) {
00421 #endif
00422       ast_log(LOG_WARNING, "Bad write (%d): %s\n", res, strerror(errno));
00423       return -1;
00424    }
00425 
00426    s->bytes += f->datalen;
00427       
00428    return 0;
00429 
00430 }
00431 
00432 static int wav_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
00433 {
00434    off_t min, max, cur, offset = 0, samples;
00435 
00436    samples = sample_offset * 2; /* SLINEAR is 16 bits mono, so sample_offset * 2 = bytes */
00437    min = 44; /* wav header is 44 bytes */
00438    cur = ftello(fs->f);
00439    fseeko(fs->f, 0, SEEK_END);
00440    max = ftello(fs->f);
00441    if (whence == SEEK_SET)
00442       offset = samples + min;
00443    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
00444       offset = samples + cur;
00445    else if (whence == SEEK_END)
00446       offset = max - samples;
00447         if (whence != SEEK_FORCECUR) {
00448       offset = (offset > max)?max:offset;
00449    }
00450    /* always protect the header space. */
00451    offset = (offset < min)?min:offset;
00452    return fseeko(fs->f, offset, SEEK_SET);
00453 }
00454 
00455 static int wav_trunc(struct ast_filestream *fs)
00456 {
00457    if (ftruncate(fileno(fs->f), ftello(fs->f)))
00458       return -1;
00459    return update_header(fs->f);
00460 }
00461 
00462 static off_t wav_tell(struct ast_filestream *fs)
00463 {
00464    off_t offset;
00465    offset = ftello(fs->f);
00466    /* subtract header size to get samples, then divide by 2 for 16 bit samples */
00467    return (offset - 44)/2;
00468 }
00469 
00470 static const struct ast_format wav_f = {
00471    .name = "wav",
00472    .exts = "wav",
00473    .format = AST_FORMAT_SLINEAR,
00474    .open =  wav_open,
00475    .rewrite = wav_rewrite,
00476    .write = wav_write,
00477    .seek = wav_seek,
00478    .trunc = wav_trunc,
00479    .tell =  wav_tell,
00480    .read = wav_read,
00481    .close = wav_close,
00482    .buf_size = WAV_BUF_SIZE + AST_FRIENDLY_OFFSET,
00483    .desc_size = sizeof(struct wav_desc),
00484 };
00485 
00486 static int load_module(void)
00487 {
00488    if (ast_format_register(&wav_f))
00489       return AST_MODULE_LOAD_FAILURE;
00490    return AST_MODULE_LOAD_SUCCESS;
00491 }
00492 
00493 static int unload_module(void)
00494 {
00495    return ast_format_unregister(wav_f.name);
00496 }  
00497 
00498 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Microsoft WAV format (8000Hz Signed Linear)");

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