/* -*- Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
* Copyright (c) Xerox Corporation 1997. 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linking this file statically or dynamically with other modules is making
* a combined work based on this file. Thus, the terms and conditions of
* the GNU General Public License cover the whole combination.
*
* In addition, as a special exception, the copyright holders of this file
* give you permission to combine this file with free software programs or
* libraries that are released under the GNU LGPL and with code included in
* the standard release of ns-2 under the Apache 2.0 license or under
* otherwise-compatible licenses with advertising requirements (or modified
* versions of such code, with unchanged license). You may copy and
* distribute such a system following the terms of the GNU GPL for this
* file and the licenses of the other code concerned, provided that you
* include the source code of that other code when and as the GNU GPL
* requires distribution of source code.
*
* Note that people who make modified versions of this file are not
* obligated to grant this special exception for their modified versions;
* it is their choice whether to do so. The GNU General Public License
* gives permission to release a modified version without this exception;
* this exception also makes it possible to release a modified version
* which carries forward this exception.
*/
/*
* Copyright (c) 1995 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Network Research
* Group at Lawrence Berkeley National Laboratory.
* 4. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
*/
#ifndef lint
static const char rcsid[] =
"@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/apps/vatrcvr.cc,v 1.7 2005/08/26 05:05:28 tomh Exp $";
#endif
#ifndef WIN32
#include <sys/time.h>
#endif
#include "agent.h"
#include "rtp.h"
#include "adaptive-receiver.h"
#include "vat.h"
//Most of this code is taken from the decoder.cc file of the publicly available
//vat code with some minor midifications.
class VatRcvr : public AdaptiveRcvr {
public:
VatRcvr();
protected:
int adapt(Packet *pkt, u_int32_t time);
void count(int statno);
u_int32_t hostoffset_;
int32_t var_; //variance in this host's interarrival time
u_int32_t playout_; // playout delay (in media units)
int maxdel_;
int block_size_;
int lecture_mode_;
u_int32_t lastrecv_;
u_int32_t predicted_drop_;
int delvar_;
/*XXX*/
#define MAXSTAT 16
struct statcntr {
const char* name;
u_int cnt;
} stat_[MAXSTAT];
int nstat_;
};
inline void VatRcvr::count(int statno)
{
++stat_[statno].cnt;
}
inline int absdiff(int x, int y)
{
register int r = y - x;
return (r < 0? -r : r);
}
static inline int newoffset(
int nvar,
int playout,
int maxdel, int mindel, int lecture)
{
register int offset = nvar;
if (offset > maxdel)
offset = maxdel;
register int diff = playout - offset;
if (diff > 0) {
// offset going down: in LectureMode, drop at most
// one frametime per talkspurt. In ConferenceMode,
// drop at most 1/2 of difference.
if (lecture) {
if (diff > FRAMESIZE) {
if (playout > (maxdel * 3) / 4 &&
diff > 10 * FRAMESIZE)
diff = 5 * FRAMESIZE;
else
diff = FRAMESIZE;
}
} else
diff >>= 1;
offset = playout - diff;
} else if (-diff > maxdel) {
// offset going way up: only allow 3/4 of max.
offset = (maxdel * 3) / 4;
}
if (offset > (maxdel * 7) / 8)
offset = (maxdel * 7) / 8;
else if (offset < mindel)
offset = mindel;
return (offset);
}
int VatRcvr::adapt(Packet *pkt, u_int32_t local_clock)
{
hdr_cmn* ch = hdr_cmn::access(pkt);
register u_int32_t tstamp = (int)ch->timestamp();
register int hoff = (int)hostoffset_;
register int offset = (tstamp + hoff - local_clock) &~ 3;
hdr_rtp *rh = hdr_rtp::access(pkt);
int new_ts = rh->flags() & RTP_M ;
//struct timeval tv;
//static long int last;
/* printf("%1d %10d %10d\n", new_ts ? 1: 0, tstamp, local_clock);*/
/* printf("%u\n", tstamp); */
//gettimeofday(&tv, NULL);
//last = tv.tv_usec - last;
//if (last < 0)
// last += 1000000;
/*
printf("%u %u %u ==> %d\n", tstamp, hoff, local_clock, offset);
printf("%u %d\n", tv.tv_usec, last);
*/
//last = tv.tv_usec;
/* printf("%u ==> %d\n", local_clock, offset); */
if (hoff == 0 || new_ts) {
/* if (hoff == 0) { */
/* printf("TS: var = %d playback = %d", var_ >> (VAR_FILTER + 3),
playout_ >> (PLAYO_FILTER + 3)); */
/*
* start of new talk spurt --
* use accumulated variance to compute new offset if
* this would make a significant change. We change if
* - the variance is currently 'small', or
* - the change would be a least a packet time
*/
register int nvar = var_ >> (VAR_FILTER - VAR_MULT);
offset = playout_ >> PLAYO_FILTER;
if (nvar < 3*FRAMESIZE || absdiff(nvar, offset) >= FRAMESIZE) {
offset = newoffset(nvar, offset, maxdel_,
block_size_, lecture_mode_);
/*
* assume that a talk spurt starts with TALK_LEAD
* samples of history & subtract them off if possible.
*/
/* CHANGED THIS PART OF VAT CODE AS WELL */
if (new_ts) {
offset -= 4 * FRAMESIZE;
if (offset < block_size_)
offset = block_size_;
}
}
hostoffset_ = local_clock - tstamp + offset;
/* printf(" new playback = %d\n", offset >> 3); */
} else if (offset < 0 || offset > maxdel_) {
/* printf("LP: late by %d var = %d playback = %d", (0 - (offset >> 3)),
var_ >> (VAR_FILTER + 3), playout_ >> (PLAYO_FILTER + 3)); */
/*
* packet out of range -- if last packet also out of
* range or if the delay would increase, resync.
*/
if (offset < 0 || predicted_drop_ == tstamp) {
offset = newoffset(var_ >> (VAR_FILTER - VAR_MULT),
playout_ >> PLAYO_FILTER,
maxdel_, block_size_,
lecture_mode_);
hostoffset_ = local_clock - tstamp + offset;
} else {
/* printf("late packet\n"); */
predicted_drop_ = tstamp + block_size_;
lastrecv_ = tstamp - local_clock;
count(STAT_LATE);
return (-1);
}
/* printf(" new playback = %d\n", offset >> 3); */
} else {
// packet in range, update interarrival var. est.
register int nvar = var_;
register int off = tstamp - local_clock - lastrecv_;
/* printf("offset = %3d", off >> 3); */
if (off < 0)
off = -off;
off -= (nvar >> VAR_FILTER);
var_ = nvar + off;
/* printf(" var = %3d", var_ >> 8); */
}
lastrecv_ = tstamp - local_clock;
register u_int avgplay = playout_;
playout_ = avgplay + (offset - (avgplay >> PLAYO_FILTER));
/* printf(" offset = %3d avg playout = %3d", offset >> 3, playout_ >> 8); */
offset &= ~3;
delvar_ = var_ >> VAR_FILTER;
/* printf("\n"); */
return (offset);
}
static class VatRcvrClass : public TclClass {
public:
VatRcvrClass() : TclClass("Agent/VatRcvr") {}
TclObject* create(int, const char*const*) {
return (new VatRcvr());
}
} class_vat_rcvr;
VatRcvr::VatRcvr() :
hostoffset_(0),
var_(INITIAL_OFFSET << (VAR_FILTER - VAR_MULT)),
playout_(INITIAL_OFFSET << PLAYO_FILTER),
maxdel_(8000*6),
block_size_(FRAMESIZE),
lecture_mode_(0),
lastrecv_(0),
predicted_drop_(~0),
nstat_(0)
{
for (int i = 0; i < MAXSTAT; ++i) {
stat_[i].name = 0;
stat_[i].cnt = 0;
}
stat_[STAT_LATE].name = "Late-Pkts";
nstat_ = 1;
}
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