play.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_PLAYOUTBUFFER_H_)
#define _SPANDSP_PLAYOUTBUFFER_H_

/*! \page playoutbuffer_page Playout buffering

\section playoutbuffer_page_sec_1 What does it do?

\section playoutbuffer_page_sec_2 How does it work?
*/

#include "SampleArray.h"
#include "AmStats.h"
#include "LowcFE.h"
#include "AmJitterBuffer.h"
#include <set>
using std::multiset;

#define ORDER_STAT_WIN_SIZE  35
#define ORDER_STAT_LOSS_RATE 0.1

#define EXP_THRESHOLD 20
#define SHR_THRESHOLD 180

#define WSOLA_START_OFF  80
#define WSOLA_SCALED_WIN 50

// the maximum packet size that will be processed
//   640 is 80ms @ 8kHz
#define MAX_PACKET_SAMPLES 640
// search segments of size TEMPLATE_SEG samples 
#define TEMPLATE_SEG   80

// Maximum value: AUDIO_BUFFER_SIZE / 2
// Note: plc result get stored in our back buffer
#define PLC_MAX_SAMPLES (160*4) 

class AmPLCBuffer;

/** \brief base class for Playout buffer */
class AmPlayoutBuffer
{
    // Playout buffer
    SampleArrayShort buffer;

 protected:
    uint32_t r_ts;
    uint32_t w_ts;
    AmPLCBuffer *m_plcbuffer;

    uint32_t last_ts;
    bool last_ts_i;

    /* The offset RTP receive TS <-> audio_buffer TS */ 
    uint32_t recv_offset;
    /* The recv_offset initialized ?  */ 
    bool recv_offset_i;

    void buffer_put(uint32_t ts, int16_t *buf, int len);
    void buffer_get(uint32_t ts, int16_t *buf, int len);

    virtual void write_buffer(uint32_t ref_ts, uint32_t ts, int16_t *buf, int len);
    virtual void direct_write_buffer(uint32_t ts, int16_t *buf, int len);
 public:
    AmPlayoutBuffer(AmPLCBuffer *plcbuffer);
    virtual ~AmPlayoutBuffer() {}

    virtual void write(uint32_t ref_ts, uint32_t ts, int16_t *buf, int len, bool begin_talk);
    virtual uint32_t read(uint32_t ts, int16_t *buf, int len);

    void clearLastTs() {last_ts_i = false;}
};

/** \brief adaptive playout buffer */
class AmAdaptivePlayout: public AmPlayoutBuffer
{
    // Order statistics delay estimation
    multiset<int32_t> o_stat;
    int32_t n_stat[ORDER_STAT_WIN_SIZE];
    int idx;
    double loss_rate;

    // Adaptive WSOLA
    uint32_t wsola_off;
    int shr_threshold;
    MeanArray short_scaled;

    // Second stage PLC
    int plc_cnt;
    LowcFE fec;

    // Buffers
    // stretch buffer
    int16_t p_buf[MAX_PACKET_SAMPLES*4];
    // Merging buffer (merge segment from strech + original seg)
    int16_t merge_buf[TEMPLATE_SEG];

    uint32_t time_scale(uint32_t ts, float factor, uint32_t packet_len);
    uint32_t next_delay(uint32_t ref_ts, uint32_t ts);

public:
    AmAdaptivePlayout(AmPLCBuffer *);

    /* Write len samples beginning from timestamp ts from buf */
    void direct_write_buffer(unsigned int ts, int16_t *buf, unsigned int len);

    /* Write len samples which beginn from timestamp ts from buf
       reference ts of buffer (monotonic increasing buffer ts) is ref_ts */
    void write_buffer(uint32_t ref_ts, uint32_t ts, int16_t *buf, uint32_t len);

    /* Read len samples beginn from timestamp ts into buf */
    uint32_t read(uint32_t ts, int16_t *buf, uint32_t len);
};

/** \brief adaptive jitter buffer */
class AmJbPlayout : public AmPlayoutBuffer
{
private:
    AmJitterBuffer m_jb;
    unsigned int m_last_rtp_endts;

protected:
    void direct_write_buffer(unsigned int ts, int16_t *buf, unsigned int len);
    void prepare_buffer(unsigned int ts, unsigned int ms);

public:
    AmJbPlayout(AmPLCBuffer *plcbuffer);

    uint32_t read(uint32_t ts, int16_t *buf, uint32_t len);
    void write(uint32_t ref_ts, uint32_t rtp_ts, int16_t *buf, uint32_t len, bool begin_talk);
};

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

#if defined(__cplusplus)
}
#endif

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