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/* Jitter buffering functions
*
* (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
* All Rights Reserved
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <math.h>
#include "sample.h"
#include "debug.h"
#include "jitter.h"
/* create jitter buffer */
int jitter_create(jitter_t *jitter, int length)
{
memset(jitter, 0, sizeof(*jitter));
jitter->spl = calloc(length * sizeof(sample_t), 1);
if (!jitter->spl) {
PDEBUG(DDSP, DEBUG_ERROR, "No memory for jitter buffer.\n");
return -ENOMEM;
}
jitter->len = length;
return 0;
}
void jitter_destroy(jitter_t *jitter)
{
if (jitter->spl) {
free(jitter->spl);
jitter->spl = NULL;
}
}
/* store audio in jitterbuffer
*
* stop if buffer is completely filled
*/
void jitter_save(jitter_t *jb, sample_t *samples, int length)
{
sample_t *spl;
int inptr, outptr, len, space;
int i;
spl = jb->spl;
inptr = jb->inptr;
outptr = jb->outptr;
len = jb->len;
space = (outptr - inptr + len - 1) % len;
if (space < length)
length = space;
for (i = 0; i < length; i++) {
spl[inptr++] = *samples++;
if (inptr == len)
inptr = 0;
}
jb->inptr = inptr;
}
/* get audio from jitterbuffer
*/
void jitter_load(jitter_t *jb, sample_t *samples, int length)
{
sample_t *spl;
int inptr, outptr, len, fill;
int i, ii;
spl = jb->spl;
inptr = jb->inptr;
outptr = jb->outptr;
len = jb->len;
fill = (inptr - outptr + len) % len;
if (fill < length)
ii = fill;
else
ii = length;
/* fill what we got */
for (i = 0; i < ii; i++) {
*samples++ = spl[outptr++];
if (outptr == len)
outptr = 0;
}
/* on underrun, fill with silence */
for (; i < length; i++) {
*samples++ = 0;
}
jb->outptr = outptr;
}
void jitter_clear(jitter_t *jb)
{
jb->inptr = jb->outptr = 0;
}
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