src/spandsp/jitter.h

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/*
 * SpanDSP - a series of DSP components for telephony
 *
 * jitterbuffer.h - 
 *
 * Written by Steve Underwood <steveu@coppice.org>
 *
 * Copyright (C) 2007 Steve Underwood
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1,
 * as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

/*! \file */

#if !defined(_SPANDSP_JITTERBUFFER_H_)
#define _SPANDSP_JITTERBUFFER_H_

/*! \page jitterbuffer_page Jitter buffering

\section jitterbuffer_page_sec_1 What does it do?

\section jitterbuffer_page_sec_2 How does it work?
*/

#define INITIAL_JITTER      640 // 80 miliseconds
#define MAX_JITTER          16000 // 2 seconds
#define RESYNC_THRESHOLD    2

typedef struct
{
    int16_t data[AUDIO_BUFFER_SIZE*2];
    uint32_t size;
    uint32_t ts;
public:
    packet_t *next;
    packet_t *prev;
    void init(const int16_t *data, uint32_t size, uint32_t ts);

    uint32_t size() const { return size; }
    int16_t *data() { return data; }

    bool operator < (const Packet&) const;
} packet_t;

typedef struct
{
private:
    packet_t packets[MAX_JITTER/80];
    packet_t *free_packets;

public:
    packet_allocator(void);
    packet_t *alloc(const int16_t *data, uint32_t size, uint32_t ts);
} packet_allocator_t;

typedef struct
{
    packet_allocator_t allocator;
    packet_t *head;
    packet_t *tail;
    int ts_inited;
    timestamp_t last_ts;
    timestamp_t last_resync_ts;
    timestamp_t last_audio_ts;
    timestamp_t ts_delta;
    int ts_delta_inited;
    int delay_count;
    uint32_t jitter;
    int force_resync;
#ifdef DEBUG_PLAYOUTBUF
    uint32_t ts_delta_start;
#endif
} playout_state_t;

#if defined(__cplusplus)
extern "C"
{
#endif

void playout_put(playout_state_t *s, const int16_t *data, timestamp_t size, timestamp_t ts, int begin_talk);
int playout_get(playout_state_t *s, timestamp_t ts, uint32_t ms, int16_t *out, uint32_t *size, timestamp_t *out_ts);

#if defined(__cplusplus)
}
#endif

#endif
/*- End of file ------------------------------------------------------------*/