Asterisk
/
asterisk
mirror of https://github.com/asterisk/asterisk
1
0
Fork 0
Code Issues Releases Wiki Activity

Document the MSGSM format, and fix the uncalculated number of samples

Browse Source 
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@19673 65c4cc65-6c06-0410-ace0-fbb531ad65f3
1.4
Tilghman Lesher 19 years ago
parent 5e43f18529
commit 3042c79182
1 changed files with 68 additions and 27 deletions
Show Stats Download Patch File Download Diff File

95
formats/format_wav_gsm.c
Unescape View File

@ -56,7 +56,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#define GSM_FRAME_SIZE 33
#define MSGSM_FRAME_SIZE 65
#define MSGSM_DATA_OFS 60 /* offset of data bytes */
#define MSGSM_DATA_OFFSET 60 /* offset of data bytes */
#define GSM_SAMPLES 160 /* samples in a GSM block */
#define MSGSM_SAMPLES (2*GSM_SAMPLES) /* samples in an MSGSM block */
@ -219,15 +219,16 @@ static int check_header(FILE *f)
static int update_header(FILE *f)
{
off_t cur,end,bytes;
int datalen,filelen;
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_OFS;
bytes = end - MSGSM_DATA_OFFSET;
samples = bytes / GSM_FRAME_SIZE * MSGSM_SAMPLES;
datalen = htoll((bytes + 1) & ~0x1);
filelen = htoll(52 + ((bytes + 1) & ~0x1));
filelen = htoll(MSGSM_DATA_OFFSET - 8 + ((bytes + 1) & ~0x1));
if (cur < 0) {
ast_log(LOG_WARNING, "Unable to find our position\n");
return -1;
@ -237,7 +238,15 @@ static int update_header(FILE *f)
return -1;
}
if (fwrite(&filelen, 1, 4, f) != 4) {
ast_log(LOG_WARNING, "Unable to set write file size\n");
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)) {
@ -245,7 +254,7 @@ static int update_header(FILE *f)
return -1;
}
if (fwrite(&datalen, 1, 4, f) != 4) {
ast_log(LOG_WARNING, "Unable to set write datalen\n");
ast_log(LOG_WARNING, "Unable to write datalen\n");
return -1;
}
if (fseeko(f, cur, SEEK_SET)) {
@ -257,78 +266,111 @@ static int update_header(FILE *f)
static int write_header(FILE *f)
{
unsigned int hz=htoll(DEFAULT_SAMPLE_RATE); /* XXX the following are relate to DEFAULT_SAMPLE_RATE ? */
unsigned int bhz = htoll(1625);
unsigned int hs = htoll(20);
/* 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);
unsigned int fhs = htoll(4);
unsigned int x_1 = htoll(65);
unsigned short x_2 = htols(2);
unsigned short x_3 = htols(320);
unsigned int y_1 = htoll(20160);
/* Each block of data is exactly 65 bytes in size. */
unsigned short block_align = htols(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;
}
if (fwrite("WAVEfmt ", 1, 8, f) != 8) {
/* 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;
}
if (fwrite(&hs, 1, 4, f) != 4) {
/* 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;
}
if (fwrite(&hz, 1, 4, f) != 4) {
/* 24: Subchunk 1: Sample rate */
if (fwrite(&sample_rate, 1, 4, f) != 4) {
ast_log(LOG_WARNING, "Unable to write header\n");
return -1;
}
if (fwrite(&bhz, 1, 4, f) != 4) {
/* 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;
}
if (fwrite(&x_1, 1, 4, f) != 4) {
/* 32: Subchunk 1: Block align */
if (fwrite(&block_align, 1, 2, f) != 4) {
ast_log(LOG_WARNING, "Unable to write header\n");
return -1;
}
if (fwrite(&x_2, 1, 2, f) != 2) {
/* 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;
}
if (fwrite(&x_3, 1, 2, f) != 2) {
/* 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;
}
if (fwrite(&fhs, 1, 4, f) != 4) {
/* 44: Subchunk 2: Size (minus 8) */
if (fwrite(&factsize, 1, 4, f) != 4) {
ast_log(LOG_WARNING, "Unable to write header\n");
return -1;
}
if (fwrite(&y_1, 1, 4, f) != 4) {
/* 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;
@ -454,7 +496,7 @@ static int wav_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
off_t offset=0, distance, max;
struct wavg_desc *s = (struct wavg_desc *)fs->private;
off_t min = MSGSM_DATA_OFS;
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 */
@ -496,8 +538,7 @@ static off_t wav_tell(struct ast_filestream *fs)
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 */
/* XXX why 52 ? */
return (offset - 52)/MSGSM_FRAME_SIZE*MSGSM_SAMPLES;
return (offset - MSGSM_DATA_OFFSET)/MSGSM_FRAME_SIZE*MSGSM_SAMPLES;
}
static struct ast_format_lock me = { .usecnt = -1 };

Write Preview
Loading…
Cancel
Save