ref: 31b97c11f06cde9508bfb4cc57f40175f683bdac
dir: /src/vox.c/
/************************************************************************
* SOX *
* *
* AUDIO FILE PROCESSING UTILITY *
* *
* Project : SOX *
* File : vox.c *
* *
* Version History : V12.17.4 - Tony Seebregts *
* 5 May 2004 *
* *
* Description : SOX file format handler for Dialogic/Oki ADPCM VOX *
* files. *
* *
* Notes : Coded from SOX skeleton code supplied with SOX source. *
* *
************************************************************************/
/************************************************************************
* July 5, 1991 *
* *
* Copyright 1991 Lance Norskog And Sundry Contributors *
* *
* This source code is freely redistributable and may be used for any *
* purpose. This copyright notice must be maintained. *
* *
* Lance Norskog And Sundry Contributors are not responsible for the *
* consequences of using this software. *
* *
************************************************************************/
#include "adpcms.h"
#include "st_i.h"
typedef struct voxstuff
{
struct adpcm_struct encoder;
struct {
uint8_t byte; /* write store */
uint8_t flag;
} store;
st_fileinfo_t file;
} *vox_t;
/******************************************************************************
* Function : voxstart
* Description: Initialises the file parameters and ADPCM codec state.
* Parameters : ft - file info structure
* Returns : int - ST_SUCCESS
* ST_EOF
* Exceptions :
* Notes : 1. VOX file format is 4-bit OKI ADPCM that decodes to
* to 12 bit signed linear PCM.
* 2. Dialogic only supports 6kHz, 8kHz and 11 kHz sampling
* rates but the codecs allows any user specified rate.
******************************************************************************/
static int voxstart(ft_t ft)
{
vox_t state = (vox_t) ft->priv;
/* ... setup file info */
state->file.buf = (char *) xmalloc(ST_BUFSIZ);
state->file.size = ST_BUFSIZ;
state->file.count = 0;
state->file.pos = 0;
state->file.eof = 0;
state->store.byte = 0;
state->store.flag = 0;
adpcm_init(&state->encoder, 1);
ft->signal.channels = 1;
return st_rawstart(ft, st_true, st_false, ST_ENCODING_OKI_ADPCM, ST_SIZE_16BIT, ST_OPTION_DEFAULT);
}
static int imastart(ft_t ft)
{
vox_t state = (vox_t) ft->priv;
/* ... setup file info */
state->file.buf = (char *) xmalloc(ST_BUFSIZ);
state->file.size = ST_BUFSIZ;
state->file.count = 0;
state->file.pos = 0;
state->file.eof = 0;
state->store.byte = 0;
state->store.flag = 0;
adpcm_init(&state->encoder, 0);
ft->signal.channels = 1;
return st_rawstart(ft, st_true, st_false, ST_ENCODING_IMA_ADPCM, ST_SIZE_16BIT, ST_OPTION_DEFAULT);
}
/******************************************************************************
* Function : read
* Description: Fills an internal buffer from the VOX file, converts the
* OKI ADPCM 4-bit samples to 12-bit signed PCM and then scales
* the samples to full range 16 bit PCM.
* Parameters : ft - file info structure
* buffer - output buffer
* length - size of output buffer
* Returns : int - number of samples returned in buffer
* Exceptions :
* Notes :
******************************************************************************/
static st_size_t read(ft_t ft, st_sample_t * buffer, st_size_t len)
{
vox_t state = (vox_t) ft->priv;
st_size_t n;
uint8_t byte;
for (n = 0; n < (len&~1) && st_readb(ft, &byte) == ST_SUCCESS; n += 2) {
short word = adpcm_decode(byte >> 4, &state->encoder);
*buffer++ = ST_SIGNED_WORD_TO_SAMPLE(word, ft->clips);
word = adpcm_decode(byte, &state->encoder);
*buffer++ = ST_SIGNED_WORD_TO_SAMPLE(word, ft->clips);
}
return n;
}
/******************************************************************************
* Function : stopread
* Description: Frees the internal buffer allocated in voxstart/imastart.
* Parameters : ft - file info structure
* Returns : int - ST_SUCCESS
* Exceptions :
* Notes :
******************************************************************************/
static int stopread(ft_t ft)
{
vox_t state = (vox_t) ft->priv;
free(state->file.buf);
return (ST_SUCCESS);
}
/******************************************************************************
* Function : write
* Description: Converts the supplied buffer to 12 bit linear PCM and encodes
* to OKI ADPCM 4-bit samples (packed a two nibbles per byte).
* Parameters : ft - file info structure
* buffer - output buffer
* length - size of output buffer
* Returns : int - ST_SUCCESS
* ST_EOF
* Exceptions :
* Notes :
******************************************************************************/
static st_size_t write(ft_t ft, const st_sample_t * buffer, st_size_t length)
{
vox_t state = (vox_t) ft->priv;
st_size_t count = 0;
uint8_t byte = state->store.byte;
uint8_t flag = state->store.flag;
short word;
while (count < length) {
word = ST_SAMPLE_TO_SIGNED_WORD(*buffer++, ft->clips);
byte <<= 4;
byte |= adpcm_encode(word, &state->encoder) & 0x0F;
flag++;
flag %= 2;
if (flag == 0) {
state->file.buf[state->file.count++] = byte;
if (state->file.count >= state->file.size) {
st_writebuf(ft, state->file.buf, 1, state->file.count);
state->file.count = 0;
}
}
count++;
}
/* ... keep last byte across calls */
state->store.byte = byte;
state->store.flag = flag;
return (count);
}
/******************************************************************************
* Function : stopwrite
* Description: Flushes any leftover samples and frees the internal buffer
* allocated in voxstart/imastart.
* Parameters : ft - file info structure
* Returns : int - ST_SUCCESS
* Exceptions :
* Notes :
******************************************************************************/
static int stopwrite(ft_t ft)
{
vox_t state = (vox_t) ft->priv;
uint8_t byte = state->store.byte;
uint8_t flag = state->store.flag;
/* ... flush remaining samples */
if (flag != 0) {
byte <<= 4;
byte |= adpcm_encode(0, &state->encoder) & 0x0F;
state->file.buf[state->file.count++] = byte;
}
if (state->file.count > 0)
st_writebuf(ft, state->file.buf, 1, state->file.count);
free(state->file.buf);
return (ST_SUCCESS);
}
const st_format_t *st_vox_format_fn(void)
{
static char const * names[] = {"vox", NULL};
static st_format_t driver = {
names, NULL, 0,
voxstart, read, stopread,
voxstart, write, stopwrite,
st_format_nothing_seek
};
return &driver;
}
const st_format_t *st_ima_format_fn(void)
{
static char const * names[] = {"ima", NULL};
static st_format_t driver = {
names, NULL, 0,
imastart, read, stopread,
imastart, write, stopwrite,
st_format_nothing_seek
};
return &driver;
}