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