使用OpenH323开发

bricks 原创
[email protected]
必备软件包可以从 http://www.open h323.org 下载.
pwlib是一套跨平台的C++的开发库,使基于pwlib上开发的应用能够很少量的移植就可以跑在windows和unix的平台上.
Open323是澳洲的一家公司驱动的open source的 h323协议族实现, 还不够十分的完整, 但是已经是非常的难得了.
在windows上和linux下都能编译使用, 我已经试过了. Windows上编译他们比较麻烦, 注意的是一定要用batch building. 在VC7上编译open h323的动态连接库的时候, VS.net会崩溃, 注意避开, 不过也可以试试看看现象, 如果能够解决, 请告诉我一下.
在linux上编译就没有什么好说的了, 设好两个环境变量(PWLIBDIR, OPEN H323DIR), 就可以在展开的目录下编译了, 先编译PWLIB, 再编译OPEN H323, 别忘了将相应xx/lib写到/etc/ld.so.conf下. 我这里可能对安装讲的不够详细, open h323讲的非常详细, 大家可以去看.

以linux平台为例:
使用pwlib, 在成功编译之后, 到$(PWLIBDIR)/SAMPLES/
这里是一些例子, hello_world 是个非常简单的工程, 从这里我们可以看到如何写使用pwlib的Makefile:
# Simple makefile for the hello world program
PROG = hello
SOURCES = hello.cxx
ifndef PWLIBDIR
PWLIBDIR=$(HOME)/pwlib
endif
include $(PWLIBDIR)/make/ptlib.mak
关键是包含了一个ptlib.mak

hello.cxx
#include
class Hello : public PProcess
{
PCLASSINFO(Hello, PProcess)
public:
void Main();
};

PCREATE_PROCESS(Hello)
void Hello::Main()
{
cout << "Hello world!/n";
}
非 常有代表性. Include $(PWLIBDIR)/make/ptlib.mak 这样就可以make all, make debug的之类的进行编译, 需要的头文件库都会替你安排好. 编译的结果就会放在obj_linux_x86_xx, xx 表示你用的是debug编译还是其他, 如果是debug, xx就是d.

使用pwlib的程序, 必然要有一个PProcess的子类, 作为整个进程, 这是指在console模式下, gui模式的用PApplication这个我没有用过. Pwlib里面的类大多都是P开头, (可能是取其兼容的意思, 跨平台的特性, 我瞎猜的), 在进程中如果想创建新的线程就创建PThread子类的对象, 对于这种关于过程的类,都有Main函数等待子类去实现.
在使用所有的P类的 时候, 注意使用两个宏, 声明类的时候PCLASSINFO(Hello, PProcess); 分号可以加, 也可不加. PProcess的子类的实现的时候要用PCREATE_PROCESS(Hello);, 这个东西把main()之类的系统入口封装了, 由他来调用Main()成员函数. 在使用线程的时候, 如果想让线程从线程的对象一创建就运行, 就应该在PThread子类中的构造函数中调用父类的Resume(). 关于pwlib先说这些, 在使用Open h323的时候到处都会用到pwlib的东西和概念.

Open h323:
终于进入正题了, 先粗略的讲点概念(多余了), H323是 指协议族了, 包含了很多规范, 它来自ITU, 应会议的需要而产生, 信令相关的东西用H225 H245,类似Q931,用ASN1编码后在tcp之上传输, 数据相关的就是编码解码的东西了(包括音频视频), 音频g711(alaw, ulaw)了等等多了, 视频h261, 好像h263还没实现.
在 H323的系统里进行通讯的角色实体就是Endpoint, 每个Endpoint可以有很多的Connection, 每个Endpoint也可以拥有很多的逻辑角色, 这个不讨论.
Endpoint 在Open h323中就是类 H323Endpoint的实例
Connection 在Open h323中就是 H323Connection的实例
当Endpoint接收了一个远程的连接请求, Endpoint就会创建一个 H323Connection;
当Endpoint发出一个连接的请求, Endpoint也会创建一个 H323Connection
Connection 就会进入一个状态机, 在各个状态中, Connetcion会相应的执行相应的方法, 这些方法, 大多都是Onxxxxx(), 是虚函数, 我们可以自己通过继承 H323Connection创建其子类, 并且在我们想做事的时机去重载相应的虚函数. 这是使用Open h323的一个基本的思路.
现在我们可以看看如何写一个自己 H323的Endpoint, 让它能够和netmeeting互操作.成功编译Open h323后在它的samples的目录下面有几个例子, mfc是指在windows下如何使用MFC和Open h323一起开发, 还有simple, 这是个简单的 H323的Endpoint的实现, 作为理解Open H323的库如何使用和开发的技巧方法已经足够了.
程序运行主线:
PWLIB(PCREATE_PROCESS(Simple H323Process))--?Simple H323Process:: Simple H323Process()--?Simple H323Process::Main();
Main()如果结束, 这个程序就结束了, 可是Main()里面有个死循环, 写过图形程序的朋友们都知道, 这就是在等消息来呀. 在VC中称之为Interface thread.
程序注解:
main.h
这个文件包含了程序用到的所有类的声明, 一般应该至少有三个类:
来自PProcess的一个主进程的, 或者说作为界面线程的;(只有一个对象)
来自 H323Endpoint的, 标识这个 H323端点的;(只有一个对象)
来自 H323Connection的, 标识所有和这个 H323端点相关的连接;(可以有多个)

#ifndef _Simple H323_MAIN_H
#define _Simple H323_MAIN_H
//避免头文件重复包含

#include

class Simple H323EndPoint : public H323EndPoint
{
//使用Pwlib的要求, 就像使用MFC, 有n多的宏, 可以看看pwlib的源码,
//宏展开都干了什么
PCLASSINFO(Simple H323EndPoint, H323EndPoint);

public:
Simple H323EndPoint();
~Simple H323EndPoint();

// overrides from H323EndPoint
// 重载 H323EndPoint的函数

// 当收到一个远程的呼入和发出呼出的请求的时候
virtual H323Connection * CreateConnection(unsigned callReference);
// 有远程的请求来到, 这是在CreateConnection之后的
virtual BOOL OnIncomingCall( H323Connection &, const H323SignalPDU &, H323SignalPDU &);
//应答远程的呼入
virtual H323Connection::AnswerCallResponse OnAnswerCall( H323Connection &, const PString &, const H323SignalPDU &, H323SignalPDU
&);
//当连接被Forward
virtual BOOL OnConnectionForwarded( H323Connection &, const PString &, const H323SignalPDU &);
//当连接建立
virtual void OnConnectionEstablished( H323Connection & connection, const PString & token);
//当连接撤销
virtual void OnConnectionCleared( H323Connection & connection, const PString & clearedCallToken);
//当连接需要打开声音的通道
virtual BOOL OpenAudioChannel( H323Connection &, BOOL, unsigned, H323AudioCodec &);

// New functions
// 自己添加的新函数, 父类中不存在
BOOL Initialise(PArgList &);
BOOL SetSoundDevice(PArgList &, const char *, PSoundChannel::Directions);
// 每个连接会有一个Token来唯一标识
PString currentCallToken;

protected:
BOOL autoAnswer;
PString busyForwardParty;
};

class Simple H323Connection : public H323Connection
{
PCLASSINFO(Simple H323Connection, H323Connection);

public:
//创建连接对象的时候将Endpoint的对象以引用传进来
//引用的概念就是将整个对象暴露给你的意思, 不是复制了一份的意思,
//对象还是原来的对象, 所以在Connection中修改了EndPoint的某些属性后
//就是在操作着传进来的对象, 这是C++的基本概念, Open H323大量的使用
//引用传递对象, 对引用的概念要理解
Simple H323Connection(Simple H323EndPoint &, unsigned);

//重载了两个父类的函数

// 当打开逻辑通道的时候(等于没说)
virtual BOOL OnStartLogicalChannel( H323Channel &);
// 处理用户输入, 这个不是之运行这个程序的用户,而是这个连接上的用户输入
// 一般应该是拨号了之类的,
virtual void OnUserInputString(const PString &);

protected:
// 快速连接??
BOOL noFastStart;
};
class Simple H323Process : public PProcess
{
//主进程, 类似VC的用户界面线程,
//他是整个程序的入口点, 和结束点
//创建了EndPoint对象后会有好几个线程启动
//这个就是主线程
PCLASSINFO(Simple H323Process, PProcess)

public:
Simple H323Process();
~Simple H323Process();
//这个函数会被自动调用, 是我们程序的入口了
void Main();
protected:

//这个 H323端点对象
Simple H323EndPoint * endpoint;
};

#endif // _Simple H323_MAIN_H

下面是main.cpp 所有的类的实现了

#include

#ifdef __GNUC__
#define H323_STATIC_LIB
#endif

#include "main.h"
#include "../../version.h"


#define new PNEW

// 这个东西里边可能封装了标准的main函数
PCREATE_PROCESS(Simple H323Process);


///////////////////////////////////////////////////////////////

//几个宏都在version.h里面定义
Simple H323Process::Simple H323Process()
: PProcess("Open H323 Project", "Simple H323",
MAJOR_VERSION, MINOR_VERSION, BUILD_TYPE, BUILD_NUMBER)
{
endpoint = NULL;
}

Simple H323Process::~Simple H323Process()
{
delete endpoint;
}
void Simple H323Process::Main()
{
cout << GetName()
<< " Version " << GetVersion(TRUE)
<< " by " << GetManufacturer()
<< " on " << GetOSClass() << << GetOSName()
<< " (" << GetOSVersion() << - << GetOSHardware() << ")/n/n";

// Get and parse all of the command line arguments.
// 分析命令行参数, 略去数行
PArgList & args = GetArguments();
args.Parse(
"a-auto-answer."
"b-bandwidth:"
"B-forward-busy:"
"D-disable:” FALSE);
if (args.HasOption(h) || (!args.HasOption(l) && args.GetCount() == 0)) {
//如果没有参数或者参数是h, 就输出如何使用, 此处略去数行
}
//这个东西暂时不管
#if PTRACING
#endif

// Create the H.323 endpoint and initialise it
// H323 EndPoint 创建了, 并且把命令参数传过去初始化, 初始化的时候做了一些事
endpoint = new Simple H323EndPoint;
if (!endpoint->Initialise(args))
return;
//看看命令行里是不是想直接呼叫另一个 H323的endpoint.有没有l(listen)的option
//如果是就MakeCall,
// See if making a call or just listening.
if (args.HasOption(l))
cout << "Waiting for incoming calls for /"" << endpoint->GetLocalUserName() << "/"/n";
else {
cout << "Initiating call to /"" << args[0] << "/"/n";
endpoint->MakeCall(args[0], endpoint->currentCallToken);
}
cout << "Press X to exit." << endl;

// Simplest possible user interface
// 简单的用户界面, 会有一个提示>
// 取pid是我加的
for (;;) {
pid_t thispid;
char prom[20];

thispid = getpid();
sprintf(prom, " H323 %d >", thispid);

cout << prom << flush;
PCaselessString cmd;
cin >> cmd;
if (cmd == "X")
break;

if (cmd.FindOneOf("HYN") != P_MAX_INDEX) {
H323Connection*connection;
//使用lock就是怕别的线程把它给删了
//因为这里正用着呢
connection=endpoint->FindConnectionWithLock(endpoint->currentCallToken);
if (connection != NULL) {
if (cmd == "H")
connection->ClearCall();
else if (cmd == "Y")
connection->AnsweringCall( H323Connection::AnswerCallNow);
else if (cmd == "N")
connection->AnsweringCall( H323Connection::AnswerCallDenied);
connection->Unlock();
}
}
}

cout << "Exiting " << GetName() << endl;
}
// Main 函数结束

// 自己的Init函数
BOOL Simple H323EndPoint::Initialise(PArgList & args)
{
// Get local username, multiple uses of -u indicates additional aliases
if (args.HasOption(u)) {
PStringArray aliases = args.GetOptionString(u).Lines();
// 设定改Endpoint的username
SetLocalUserName(aliases[0]);
// 设定Aliases 就是每个Endpoint可以有好多名字的意思
for (PINDEX i = 1; i < aliases.GetSize(); i++)
AddAliasName(aliases[i]);
}

// Set the various options
//设置静音检测否

SetSilenceDetectionMode(args.HasOption(e) ? H323AudioCodec::NoSilenceDetection
: H323AudioCodec::AdaptiveSilenceDetection);
//快速连接?
DisableFastStart(args.HasOption(f));
//H245通道
DisableH245Tunneling(args.HasOption(T));

autoAnswer = args.HasOption(a);
busyForwardParty = args.GetOptionString(B);

if (args.HasOption()) {
initialBandwidth = args.GetOptionString().AsUnsigned()*100;
if (initialBandwidth == 0) {
cerr << "Illegal bandwidth specified." << endl;
return FALSE;
}
}

if (args.HasOption(j)) {
unsigned jitter = args.GetOptionString(j).AsUnsigned();
//设定音频抖动的, 应该影响到接收的缓存
if (jitter >= 20 && jitter <= 10000)
SetMaxAudioDelayJitter(jitter);
else {
cerr << "Jitter should be between 20 milliseconds and 10 seconds." << endl;
return FALSE;
}
}

//设定声音设备
//也可以不用声音设备, 比如Open h323工程的子项目 OpenAM和OpenMCU
//都使演示了如何不使用声音物理设备的方法, 我想那里边的东西会对某些朋友们
//的需求比较合适
if (!SetSoundDevice(args, "sound", PSoundChannel::Recorder))
return FALSE;
if (!SetSoundDevice(args, "sound", PSoundChannel::Player))
return FALSE;
if (!SetSoundDevice(args, "sound-in", PSoundChannel::Recorder))
return FALSE;
if (!SetSoundDevice(args, "sound-out", PSoundChannel::Player))
return FALSE;

// 设定decode encode的能力
// H323 EndPoint在真正进行数据通讯之前要进行能力的交换, 说明自己能够接收和发送什么标准的数据, g.711是必须支持的.
// Set the default codecs available on sound cards.
AddAllCapabilities(0, 0, "GSM*{sw}");
AddAllCapabilities(0, 0, "G.711*{sw}");
AddAllCapabilities(0, 0, "LPC*{sw}");
AddAllUserInputCapabilities(0, 1);

RemoveCapabilities(args.GetOptionString(D).Lines());
ReorderCapabilities(args.GetOptionString(P).Lines());

cout << "Local username: " << GetLocalUserName() << "/n"
<< "Silence compression is " << (GetSilenceDetectionMode() == H323AudioCodec::NoSilenceDetection ? "Dis" : "En") << "abled/n"
<< "Auto answer is " << autoAnswer << "/n"
<< "FastConnect is " << (IsFastStartDisabled() ? "Dis" : "En") << "abled/n"
<< "H245Tunnelling is " << (IsH245TunnelingDisabled() ? "Dis" : "En") << "abled/n"
<< "Jitter buffer: " << GetMaxAudioDelayJitter() << " ms/n"
<< "Sound output device: /"" << GetSoundChannelPlayDevice() << "/"/n"
"Sound input device: /"" << GetSoundChannelRecordDevice() << "/"/n"
<< "Codecs (in preference order):/n" << setprecision(2) << GetCapabilities() << endl;

//启动一个来电的监听
//可以使用配置的端口, 也可以使用default的端口
// Start the listener thread for incoming calls.
H323ListenerTCP * listener;
if (args.GetOptionString(i).IsEmpty())
listener = new H323ListenerTCP(*this);
else {
PIPSocket::Address interfaceAddress(args.GetOptionString(i));
listener = new H323ListenerTCP(*this, interfaceAddress);
}
if (!StartListener(listener)) {
cerr << "Could not open H.323 listener port on "
<< listener->GetListenerPort() << endl;
delete listener;
return FALSE;
}

//这是连接GateKeeper相关的东西, 先不讨论了
// Initialise the security info
if (args.HasOption(p)) {
SetGatekeeperPassword(args.GetOptionString(p));
cout << "Enabling H.235 security access to gatekeeper." << endl;
}

// Establish link with gatekeeper if required.
if (args.HasOption(g) || !args.HasOption( )) {
H323TransportUDP * rasChannel;
if (args.GetOptionString(i).IsEmpty())
rasChannel = new H323TransportUDP(*this);
else {
PIPSocket::Address interfaceAddress(args.GetOptionString(i));
rasChannel = new H323TransportUDP(*this, interfaceAddress);
}

if (args.HasOption(g)) {
PString gkName = args.GetOptionString(g);
if (SetGatekeeper(gkName, rasChannel))
cout << "Gatekeeper set: " << *gatekeeper << endl;
else {
cerr << "Error registering with gatekeeper at /"" << gkName << /" << endl;
return FALSE;
}
}
else {
cout << "Searching for gatekeeper..." << flush;
if (DiscoverGatekeeper(rasChannel))
cout << "/nGatekeeper found: " << *gatekeeper << endl;
else {
cerr << "/nNo gatekeeper found." << endl;
if (args.HasOption( ))
return FALSE;
}
}
}

return TRUE;
}

//设定音频设备, 没什么可讲的
BOOL Simple H323EndPoint::SetSoundDevice(PArgList & args,
const char * optionName,
PSoundChannel::Directions dir)
{
if (!args.HasOption(optionName))
return TRUE;

PString dev = args.GetOptionString(optionName);

if (dir == PSoundChannel::Player) {
if (SetSoundChannelPlayDevice(dev))
return TRUE;
}
else {
if (SetSoundChannelRecordDevice(dev))
return TRUE;
}

cerr << "Device for " << optionName << " (/"" << dev << "/") must be one of:/n";

PStringArray names = PSoundChannel::GetDeviceNames(dir);
for (PINDEX i = 0; i < names.GetSize(); i++)
cerr << " /"" << names[i] << "/"/n";

return FALSE;
}

//这个函数很简单但是非常关键, 是从EndPoint中重载过来的.
//本来是return new H323Connection()的, 现在改成Simplexxx
//自己实现的一个Connection, 这样当Endpoint里面调用
//Connection的一些东西的时候, 实际上运行的是Simplexxx
//的实现, 看到C++的好处了吧, C里用函数指针也可以实现, 没有
//C++这么native.
H323Connection * Simple H323EndPoint::CreateConnection(unsigned callReference)
{
return new Simple H323Connection(*this, callReference);
}
//没什么东西, 关键是看看这个东西的调用的时机
BOOL Simple H323EndPoint::OnIncomingCall( H323Connection & connection,
const H323SignalPDU &,
H323SignalPDU &)
{
if (currentCallToken.IsEmpty())
return TRUE;

if (busyForwardParty.IsEmpty()) {
cout << "Incoming call from /"" << connection.GetRemotePartyName() << "/" rejected, line busy!" << endl;
return FALSE;
}

cout << "Forwarding call to /"" << busyForwardParty << "/"." << endl;
return !connection.ForwardCall(busyForwardParty);
}


//这个东西, 很有用, H323Connection的类里也有这个虚函数
//返回的值决定告诉远程的连接者是否接收这份连接请求
H323Connection::AnswerCallResponse
Simple H323EndPoint::OnAnswerCall( H323Connection & connection,
const PString & caller,
const H323SignalPDU &,
H323SignalPDU &)
{
currentCallToken = connection.GetCallToken();

if (autoAnswer) {
cout << "Automatically accepting call." << endl;
return H323Connection::AnswerCallNow;
}

cout << "Incoming call from /""
<< caller
<< "/", answer call (Y/n)? "
<< flush;

return H323Connection::AnswerCallPending;
}

BOOL Simple H323EndPoint::OnConnectionForwarded( H323Connection & /*connection*/,
const PString & forwardParty,
const H323SignalPDU & /*pdu*/)
{
if (MakeCall(forwardParty, currentCallToken)) {
cout << "Call is being forwarded to host " << forwardParty << endl;
return TRUE;
}

cout << "Error forwarding call to /"" << forwardParty << /" << endl;
return FALSE;
}


//连接建立时候
void Simple H323EndPoint::OnConnectionEstablished( H323Connection & connection,
const PString & token)
{
currentCallToken = token;
cout << "In call with " << connection.GetRemotePartyName() << endl;
}

//连接断开时候
void Simple H323EndPoint::OnConnectionCleared( H323Connection & connection,
const PString & clearedCallToken)
{
if (currentCallToken == clearedCallToken)
currentCallToken = PString();

PString remoteName = /" + connection.GetRemotePartyName() + /";
switch (connection.GetCallEndReason()) {
case H323Connection::EndedByRemoteUser :
cout << remoteName << " has cleared the call";
break;
case H323Connection::EndedByCallerAbort :
cout << remoteName << " has stopped calling";
break;
case H323Connection::EndedByRefusal :
cout << remoteName << " did not accept your call";
break;
case H323Connection::EndedByNoAnswer :
cout << remoteName << " did not answer your call";
break;
case H323Connection::EndedByTransportFail :
cout << "Call with " << remoteName << " ended abnormally";
break;
case H323Connection::EndedByCapabilityExchange :
cout << "Could not find common codec with " << remoteName;
break;
case H323Connection::EndedByNoAccept :
cout << "Did not accept incoming call from " << remoteName;
break;
case H323Connection::EndedByAnswerDenied :
cout << "Refused incoming call from " << remoteName;
break;
case H323Connection::EndedByNoUser :
cout << "Gatekeeper could find user " << remoteName;
break;
case H323Connection::EndedByNoBandwidth :
cout << "Call to " << remoteName << " aborted, insufficient bandwidth.";
break;
case H323Connection::EndedByUnreachable :
cout << remoteName << " could not be reached.";
break;
case H323Connection::EndedByHostOffline :
cout << remoteName << " is not online.";
break;
case H323Connection::EndedByNoEndPoint :
cout << "No phone running for " << remoteName;
break;
case H323Connection::EndedByConnectFail :
cout << "Transport error calling " << remoteName;
break;
default :
cout << "Call with " << remoteName << " completed";
}
cout << ", duration "
<< setprecision(0) << setw(5)
<< (PTime() - connection.GetConnectionStartTime())
<< endl;
}

//打开声音设备时候
//isEncoding 表示编码吗
//编码表示向外发送数据, 从声音设备读
//解码表示从网络读出数据, 写到声音设备上
//不同的方向的codec是不同的, 所以在这里有好多文章可以做
//可以给codec attach上不同的channel根据isEncoding的值
BOOL Simple H323EndPoint::OpenAudioChannel( H323Connection & connection,
BOOL isEncoding,
unsigned bufferSize,
H323AudioCodec & codec)
{
if ( H323EndPoint::OpenAudioChannel(connection, isEncoding, bufferSize, codec))
return TRUE;

cerr << "Could not open sound device ";
if (isEncoding)
cerr << GetSoundChannelRecordDevice();
else
cerr << GetSoundChannelPlayDevice();
cerr << " - Check permissions or full duplex capability." << endl;

return FALSE;
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
EndPoint的实现分析完毕.


H323Connection的实现, 这个Connection的实现太简单了.可能不足以说明问题
我也没什么好说的了
///////////////////////////////////////////////////////////////

Simple H323Connection::Simple H323Connection(Simple H323EndPoint & ep, unsigned ref)
: H323Connection(ep, ref)
{
}


BOOL Simple H323Connection::OnStartLogicalChannel( H323Channel & channel)
{
if (! H323Connection::OnStartLogicalChannel(channel))
return FALSE;

cout << "Started logical channel: ";

switch (channel.GetDirection()) {
case H323Channel::IsTransmitter :
cout << "sending ";
break;

case H323Channel::IsReceiver :
cout << "receiving ";
break;

default :
break;
}

cout << channel.GetCapability() << endl;

return TRUE;
}



void Simple H323Connection::OnUserInputString(const PString & value)
{
cout << "User input received: /"" << value << /" << endl;
}
// End of File ///////////////////////////////////////////////////////////////

总结一下基本的过程就是创建一个 H323Endpoint的对象endpoint, 创建对象后这个程序就有好多个小的线程被创建了.然后EndPoint开始监听来电, 之后判断是否直接呼叫另一个 h323的Endpoint. 然后就是一个for循环, 判断标准的输入, 并通过当前的token来lock一个Connection, 每个连接会有唯一的一个token, lock的意思是说, 在被lock的期间是不能被释放的. 根据输入的字符决定对得到的连接做什么.

OpenAM:
是个answer machine, 自动应答机, 或者是留言机. 实现的很简单, 里面对Open H323使用的思路很有价值.
./openam –n –-g711message sample_message.wav
这样运行, 用netmeeting 连接一下这个IP, netmeeting就会放一段简单的英语, 测测你的英语听力, 他在讲什么?
这个程序是一个支持多连接和并发连接的Endpoint, 但是他没有使用真正的声音设备, 放出的音从一个已有的wav文件中读出来, 远程用户的留言被录到一个文件里, 文件的名字表示了是什么时间录制的.
主要的思路是给在连接打开声音通道的时候, 根据isEncoding的值区别是录音还是放音,如果是录音, 将读文件的Channel附加在codec上, 相反写文件的Channel附件在codec上,注意这是两个codec.
这个东西给了我们一个方法, 如何使用文件IO来代替声音设备的IO来使用Open H323.


这是main.h

#ifndef _Voxilla_MAIN_H
#define _Voxilla_MAIN_H

#include
#include
#include
#include
#include

#include
#include

//主进程
class OpenAm : public PProcess
{
PCLASSINFO(OpenAm, PProcess)

public:
OpenAm();
~OpenAm();

void Main();
void RecordFile(PArgList & args);
void PlayFile(PArgList & args);

protected:
long GetCodec(const PString & codecname);
OpalLineInterfaceDevice * GetDevice(const PString & device);
};

// H323 端点
class My H323EndPoint : public H323EndPoint
{
PCLASSINFO(My H323EndPoint, H323EndPoint);

public:
My H323EndPoint(unsigned callLimit,
const PString & runCmd,
const PDirectory & dir,
int flags);

// overrides from H323EndPoint
virtual H323Connection * CreateConnection(unsigned callReference);
BOOL OnIncomingCall( H323Connection &, const H323SignalPDU &, H323SignalPDU &);

// new functions
BOOL Initialise( PConfigArgs & args);

PString GetGSMOGM() const { return gsmOgm; }
void SetGSMOGM(const PString & s) { gsmOgm = s; }

PString GetG711OGM() const { return g711Ogm; }
void SetG711OGM(const PString & s) { g711Ogm = s; }

PString GetLPC10OGM() const { return lpc10Ogm; }
void SetLPC10OGM(const PString & s) { lpc10Ogm = s; }

#ifdef SPEEX_CODEC
PString GetSPEEXOGM() const { return speexOgm; }
void SetSPEEXOGM(const PString & s) { speexOgm = s; }
#endif

PString GetG7231OGM() const { return g7231Ogm; }
void SetG7231OGM(const PString & s) { g7231Ogm = s; }

unsigned GetCallLimit() const { return callLimit; }
PString GetRunCmd() const { return runCmd; }
PDirectory GetDirectory() const { return dir; }

void SetRecordWav(const BOOL rec){ recordWav = rec; }
BOOL GetRecordWav() const { return recordWav; }

enum {
DeleteAfterRecord = 0x01,
NoRecordG7231 = 0x02,
HangupAfterPlay = 0x04
};

BOOL GetDeleteAfterRecord() const { return flags & DeleteAfterRecord; }
BOOL GetNoRecordG7231() const { return flags & NoRecordG7231; }
BOOL GetHangupAfterPlay() const { return flags & HangupAfterPlay; }

protected:
unsigned callLimit;
PString pcmOgm, g711Ogm, gsmOgm, lpc10Ogm, g7231Ogm, runCmd;
#ifdef SPEEX_CODEC
PString speexOgm;
#endif
PDirectory dir;
int flags;
BOOL recordWav;
};

class PCM_RecordFile;
class My H323Connection;
PQUEUE(PStringQueue, PString);
// Out Going Channel OGM
//就是发送语音的通道
//即是读文件的通道
class PCM_OGMChannel : public PIndirectChannel
{
PCLASSINFO(PCM_OGMChannel, PIndirectChannel);

public:
PCM_OGMChannel(My H323Connection & conn);

BOOL Read(void * buffer, PINDEX amount);
void PlayFile(PFile * chan);

BOOL Close();

void QueueFile(const PString & cmd);
void FlushQueue();

void SetRecordTrigger();
void SetHangupTrigger();

void SetPlayOnce() { playOnce = TRUE; }

protected:
virtual BOOL ReadFrame(PINDEX amount);
virtual void CreateSilenceFrame(PINDEX amount);
virtual void Synchronise(PINDEX amount);
virtual BOOL IsWAVFileValid(PWAVFile *chan);

BOOL AdjustFrame(void * buffer, PINDEX amount);

PStringQueue playQueue;

My H323Connection & conn;
PMutex chanMutex;
int silentCount;
int totalData;
BOOL recordTrigger, hangupTrigger;
BOOL closed;
BOOL playOnce;

PAdaptiveDelay ogm_delay;

PBYTEArray frameBuffer;
PINDEX frameLen, frameOffs;
};
//这个是之读的文件是个g723编码的文件, 暂时不研究这个类相关的一切
class G7231_OGMChannel : public PCM_OGMChannel
{
PCLASSINFO(G7231_OGMChannel, PCM_OGMChannel);
public:
G7231_OGMChannel(My H323Connection & conn);

protected:
BOOL ReadFrame(PINDEX amount);
void CreateSilenceFrame(PINDEX amount);
void Synchronise(PINDEX amount);
BOOL IsWAVFileValid(PWAVFile *chan);
};

//连接,都是从这个类实例出来的
class My H323Connection : public H323Connection
{
PCLASSINFO(My H323Connection, H323Connection);

public:
My H323Connection(My H323EndPoint &, unsigned);
~My H323Connection();

// overrides from H323Connection
BOOL OpenAudioChannel(BOOL, unsigned, H323AudioCodec & codec);
AnswerCallResponse OnAnswerCall(const PString &, const H323SignalPDU &, H323SignalPDU &);
BOOL OnStartLogicalChannel( H323Channel & channel);
void OnUserInputString(const PString & value);

// new functions
void StartRecording();
void Hangup();

void SetE164Number(const PString & _num)
{ e164Number = _num; }

PString GetE164Number() const
{ return e164Number; }

protected:
void OnUserInputChar(char ch);
BOOL StartMenu(int menuNumber);
BOOL ProcessMenuCmd(const PString & cmdStr);

const My H323EndPoint & ep;
PString product;
PTime callStartTime;
PTime recordStartTime;
PString basename;
PFilePath recordFn;
PString transmitCodecName, receiveCodecName;
BOOL recordTrigger;
PMutex connMutex;

PCM_RecordFile * recordFile;
PCM_OGMChannel * ogmChannel;

PString digits, lastDigits;
int currentMenu;
PStringList menuNames;

PString securityToken, e164Number;
};

//是录音
class PCM_RecordFile : public PIndirectChannel
{
PCLASSINFO(PCM_RecordFile, PIndirectChannel)

public:
PCM_RecordFile(My H323Connection & conn, const PFilePath & fn, unsigned callLimit);
~PCM_RecordFile();

BOOL Write(const void * buf, PINDEX len);
BOOL Close();
void StartRecording();

virtual void DelayFrame(PINDEX len);
virtual BOOL WriteFrame(const void * buf, PINDEX len);

BOOL WasRecordStarted() const { return recordStarted; }

protected:
My H323Connection & conn;
PTime finishTime;
PFilePath fn;
unsigned callLimit;
BOOL recordStarted;
BOOL timeLimitExceeded;
BOOL closed;
BOOL isPCM;
BOOL dataWritten;
PAdaptiveDelay delay;
PMutex pcmrecordMutex;
PFile *fileclass; // will point to a PWAVFile or PFile class
};
//录的结果是个g723文件, 我们暂时不考虑这个类相关的一切
class G7231_RecordFile : public PCM_RecordFile
{
PCLASSINFO(G7231_RecordFile, PCM_RecordFile);

public:
G7231_RecordFile(My H323Connection & conn, const PFilePath & fn, unsigned callLimit);
void DelayFrame(PINDEX len);
BOOL WriteFrame(const void * buf, PINDEX len);
};


#endif // _Voxilla_MAIN_H


// End of File ///////////////////////////////////////////////////////////////


这是main.cxx
#include
#include

#include "version.h"
#include "lpc10codec.h"

#ifdef SPEEX_CODEC
#include "speexcodec.h"
#endif

#include "mscodecs.h"
#include "opalvxml.h"
#include "main.h"

PCREATE_PROCESS(OpenAm);

#define new PNEW

//default 录音时间
#define DEFAULT_MSG_LIMIT 30
#define DEFAULT_CALL_LOG "call_log.txt"

#define G7231_SAMPLES_PER_BLOCK 240

#define CHECK_PCM 1
#define CHECK_G7231 2

#define MENU_PREFIX "UserMenu-"

static PMutex logMutex;
static PTextFile logFile;
static PFilePath logFilename = DEFAULT_CALL_LOG;

PString G7231Ext = ".g723";
PString WAVExt = ".wav";
PString PCMExt = ".sw";

//关于log的一切先不用看
static void LogMessage(const PString & str)
{
PTime now;
PString msg = now.AsString("hh:mm:ss dd/MM/yyyy") & str;
logMutex.Wait();

if (!logFile.IsOpen()) {
logFile.Open(logFilename, PFile::ReadWrite);
logFile.SetPosition(0, PFile::End);
}

logFile.WriteLine(msg);

logFile.Close();

logMutex.Signal();
}

static void LogCall(const PFilePath & fn,
const PString & from,
const PString & user,
unsigned len,
const PString & codec,
const PString & product)
{
PString addr = from;
LogMessage(addr & "/"" + user + "/"" & PString(PString::Unsigned, len) & codec & "/"" + product + "/"" & "/"" + fn + "/"");
}


///////////////////////////////////////////////////////////////

OpenAm::OpenAm()
: PProcess("Open H323 Project", "OpenAM",
MAJOR_VERSION, MINOR_VERSION, BUILD_TYPE, BUILD_NUMBER)
{
}


OpenAm::~OpenAm()
{
}


void OpenAm::Main()
{
cout << GetName()
<< " Version " << GetVersion(TRUE)
<< " by " << GetManufacturer()
<< " on " << GetOSClass() << << GetOSName()
<< " (" << GetOSVersion() << - << GetOSHardware() << ")/n/n";

// 分析命令行了
PConfigArgs args(GetArguments());

args.Parse(
"D-disable:"
"d-directory:"
"g-gatekeeper:" "n-no-gatekeeper."
"-g711-ulaw." "-no-g711-ulaw."
"-g711-alaw." "-no-g711-alaw."
"-g711message:" "-no-g711message."
"-g7231." "-no-g7231."
"-g7231message:" "-no-g7231message."
"-gsm." "-no-gsm."
"-gsmmessage:" "-no-gsmmessage."
"h-help."
"H-hangup." "-no-hangup."
"i-interface:" "-no-interface."
"k-kill." "-no-kill."
"l-limit:" "-no-limit."
"-listenport:" "-no-listenport."
"-lpc10message:" "-no-lpc10message."
"-speexmessage:" "-no-speexmessage."
"m-message:" "-no-message."
"-no-recordg7231."
#if PTRACING
"o-output:"
#endif
"P-prefer:"
"-pcm." "-no-pcm."
"-pcmmessage:" "-no-pcmmessage."
"-port:"
"q-quicknet:" "-no-quicknet:"
"r-run:" "-no-run."
"-recordraw."
"-require-gatekeeper." "-no-require-gatekeeper."
"-save."
#if PMEMORY_CHECK
"-setallocationbreakpoint:"
#endif
#if PTRACING
"t-trace."
#endif
"u-username:" "-no-username."
, FALSE);

#if PMEMORY_CHECK
if (args.HasOption("setallocationbreakpoint"))
PMemoryHeap::SetAllocationBreakpoint(args.GetOptionString("setallocationbreakpoint").AsInteger());
#endif

#if PTRACING
PTrace::Initialise(args.GetOptionCount( ),
args.HasOption(o) ? (const char *)args.GetOptionString(o) : NULL);
#endif

if (args.HasOption(h)) {
cout << "Usage : " << GetName() << " [options]/n"
"Options:/n"
" -d --directory dir : Put recorded mesages into dir/n"
" -l --limit secs : Limit recorded messages to secs duration (default " << DEFAULT_MSG_LIMIT << ")/n"
" -m --pcmmessage fn : Set outgoing message for PCM derived codecs (G.711/GSM) to fn/n"
" --g7231message fn : Set outgoing message for G723.1 codec to fn/n"
" --g711message fn : Set outgoing message for G711 codec to fn/n"
" --gsmmessage fn : Set outgoing message for GSM codec to fn/n"
" --lpc10message fn : Set outgoing message for LPC10 codec to fn/n"
#ifdef SPEEX_CODEC
" --speexmessage fn : Set outgoing message for Speex codec to fn/n"
#endif

" --recordraw : Record PCM audo in raw files (.sw) instead of .wav/n"
" -r --run cmd : Run this command after each recorded message/n"
" -k --kill : Kill recorded files after user command/n"
" -H --hangup : hangup after playing message/n"
" -u --username str : Set the local endpoint name to str/n"
" -i --interface ip : Bind to a specific interface/n"
" --listenport port : Listen on a specific port/n"
" -g --gatekeeper host: Specify gatekeeper host./n"
" -n --no-gatekeeper : Disable gatekeeper discovery./n"
" --require-gatekeeper: Exit if gatekeeper discovery fails./n"
" -D --disable codec : Disable the specified codec (may be used multiple times)/n"
" -P --prefer codec : Prefer the specified codec (may be used multiple times)/n"
#if PTRACING
" -t --trace : Enable trace, use multiple times for more detail/n"
" -o --output : File for trace output, default is stderr/n"
#endif
" --save : Save arguments in configuration file/n"
" -h --help : Display this help message/n";
return;
}

args.Save("save");

//是指有IXJ卡吗? 我想你肯定没有, 那是电话卡 不用管他
#if HAS_IXJ
if (args.GetCount() > 0) {
if (args[0] *= "record")
RecordFile(args);
else if (args[0] *= "play")
PlayFile(args);
else
cerr << "unknown command /"" << args[0] << "/"" << endl;
return;
}
#endif

unsigned callLimit = DEFAULT_MSG_LIMIT;
if (args.HasOption(l)) {
callLimit = args.GetOptionString(l).AsInteger();
if (callLimit > 3600) {
cout << "warning: maximum call length " << callLimit << " is out of range. Using " << DEFAULT_MSG_LIMIT << " instead/n";
callLimit = DEFAULT_MSG_LIMIT;
} else if (callLimit == 0)
cout << "warning: recorded message call limit disabled/n";
}
cout << "Recorded messages limited to " << callLimit << " seconds/n";

PString runCmd;
if (args.HasOption( )) {
runCmd = args.GetOptionString( );
cout << "Executing /"" << runCmd << "/" after each message" << endl;
}

PDirectory dir;
if (args.HasOption(d))
dir = args.GetOptionString(d);

int flags = 0;

if (args.HasOption("no-recordg7231")) {
cout << "Supressing recording of G723.1 messages" << endl;
flags |= My H323EndPoint::NoRecordG7231;
}
if (args.HasOption(k)) {
cout << "Deleting recorded files after processing" << endl;
if (runCmd.IsEmpty())
cout << "WARNING: recorded files will be deleted even though no run command is present" << endl;
flags |= My H323EndPoint::DeleteAfterRecord;
}

if (args.HasOption(H))
flags |= My H323EndPoint::HangupAfterPlay;

//创建 H323 EndPoint
My H323EndPoint endpoint(callLimit, runCmd, dir, flags);

PString userName = "Open H323 Answering Machine v" + GetVersion();
if (args.HasOption(u))
userName = args.GetOptionString(u);
endpoint.SetLocalUserName(userName);

if (!endpoint.Initialise(args))
return;

// start the H.323 listener
// 开始监听 H323有个默认的端口应该是1572 之类的 DefaultSignalPort, 我忘了
H323ListenerTCP * listener;
PIPSocket::Address interfaceAddress(INADDR_ANY);
WORD listenPort = H323ListenerTCP::DefaultSignalPort;

if (args.HasOption("listenport"))
listenPort = (WORD)args.GetOptionString("listenport").AsInteger();

if (args.HasOption(i))
interfaceAddress = PIPSocket::Address(args.GetOptionString(i));

listener = new H323ListenerTCP(endpoint, interfaceAddress, listenPort);

if (!endpoint.StartListener(listener)) {
cout << "Could not open H.323 listener port on "
<< listener->GetListenerPort() << endl;
delete listener;
return;
}

//gatekeeper 相关的东西我们也不必考虑 用-n这个参数这个端点就不会
//去找gatekeeper

if (args.HasOption(g)) {
PString gkName = args.GetOptionString(g);
if (endpoint.SetGatekeeper(gkName, new H323TransportUDP(endpoint)))
cout << "Gatekeeper set: " << *endpoint.GetGatekeeper() << endl;
else {
cout << "Error registering with gatekeeper at /"" << gkName << /" << endl;
return;
}
}
else if (!args.HasOption( )) {
cout << "Searching for gatekeeper..." << flush;
if (endpoint.DiscoverGatekeeper(new H323TransportUDP(endpoint)))
cout << "/nGatekeeper found: " << *endpoint.GetGatekeeper() << endl;
else {
cout << "/nNo gatekeeper found." << endl;
if (args.HasOption("require-gatekeeper"))
return;
}
}

cout << "Waiting for incoming calls for /"" << endpoint.GetLocalUserName() << /" << endl;

//瞧瞧, 这就是主进程干的这点事, Sleep的是毫秒
for (;;)
PThread::Current()->Sleep(5000);
}


///////////////////////////////////////////////////////////////


My H323EndPoint::My H323EndPoint(unsigned _callLimit,
const PString & _runCmd,
const PDirectory & _dir,
int _flags)
: callLimit(_callLimit), runCmd(_runCmd), dir(_dir), flags(_flags)
{
}

BOOL My H323EndPoint::OnIncomingCall( H323Connection & _conn,
const H323SignalPDU & setupPDU,
H323SignalPDU &)
{
//传过来的是引用, 引用这个东西必须马上赋值
My H323Connection & conn = (My H323Connection &)_conn;

// see if incoming call is to a getway address
PString number;
if (setupPDU.GetDestinationE164(number))
conn.SetE164Number(number);

return TRUE;
}
//这个没什么异常, 都这样做
H323Connection * My H323EndPoint::CreateConnection(unsigned callReference)
{
return new My H323Connection(*this, callReference);
}

//分析命令, 看看应该使用什么样的能力去交换,
// 我们在使用的时候指定—g711message
//就是说只是用g711 的alaw或者mulaw
//很多废话就不用看了
//除了和g711相关的其他都没有用处了

BOOL My H323EndPoint::Initialise( PConfigArgs & args)
{
// format for record files, raw or wav
if (args.HasOption("recordraw"))
SetRecordWav(FALSE);
else
SetRecordWav(TRUE);

// get G723.1 OGM
if (args.HasOption("g7231message"))
g7231Ogm = args.GetOptionString("g7231message");
else if (args.HasOption(m)) {
if (PFile::Exists(args.GetOptionString(m) + "_g7231" + WAVExt)) {
g7231Ogm = args.GetOptionString(m) + "_g7231" + WAVExt;
}
else if (PFile::Exists(args.GetOptionString(m) + PCMExt)) {
g7231Ogm = args.GetOptionString(m) + G7231Ext;
}
}

if (!g7231Ogm.IsEmpty()) {
if ((g7231Ogm.Find("%s") == P_MAX_INDEX) && !PFile::Exists(g7231Ogm)) {
cout << "warning: cannot open G723.1 OGM file /"" << g7231Ogm << "/"" << endl;
g7231Ogm = "";
}
}

if (g7231Ogm.IsEmpty())
cout << "No G.723.1 outgoing message set/n";
else {
cout << "Using /"" << g7231Ogm << "/" as G.723.1 outgoing message/n";
}


// Get the OGM message for the PCM codecs
// Check if the file specified exists. If it does, use it.
// If it does not exist, try with .wav and .sw extensions.
if (args.HasOption("pcmmessage")) {
pcmOgm = args.GetOptionString("pcmmessage");
}
else if (args.HasOption(m)) {
if (g7231Ogm.Find("%s") == P_MAX_INDEX) {
pcmOgm = args.GetOptionString(m);
} else {
if (PFile::Exists(args.GetOptionString(m))) {
pcmOgm = args.GetOptionString(m);
}
else if (PFile::Exists(args.GetOptionString(m) + WAVExt)) {
pcmOgm = args.GetOptionString(m) + WAVExt;
}
else if (PFile::Exists(args.GetOptionString(m) + PCMExt)) {
pcmOgm = args.GetOptionString(m) + PCMExt;
}
}
}


// By default, use the pcmOgm for all the PCM codecs, but allow the user
// to override them.
gsmOgm = pcmOgm;
g711Ogm = pcmOgm;
lpc10Ogm = pcmOgm;
#ifdef SPEEX_CODEC
speexOgm = pcmOgm;
#endif


// We can set the filename for specific codecs.
if (args.HasOption("gsmmessage"))
gsmOgm = args.GetOptionString("gsmmessage");


//这句话用的着
if (args.HasOption("g711message"))
g711Ogm = args.GetOptionString("g711message");

if (args.HasOption("lpc10message"))
lpc10Ogm = args.GetOptionString("lpc10message");
//这是一个codec设备, 你没有!
#ifdef SPEEX_CODEC
if (args.HasOption("speexmessage"))
speexOgm = args.GetOptionString("speexmessage");
#endif

// Check GSM OGM message
if (!gsmOgm.IsEmpty()) {
if ((g7231Ogm.Find("%s") == P_MAX_INDEX) && !PFile::Exists(gsmOgm)) {
cout << "warning: cannot open GSM OGM file /"" << gsmOgm << "/"" << endl;
gsmOgm = "";
}
}
if (gsmOgm.IsEmpty())
cout << "No GSM outgoing message set/n";
else {
cout << "Using /"" << gsmOgm << "/" as GSM outgoing message/n";
}

// Check G.711 OGM message
if (!g711Ogm.IsEmpty()) {
if ((g7231Ogm.Find("%s") == P_MAX_INDEX) && !PFile::Exists(g711Ogm)) {
cout << "warning: cannot open G711 OGM file /"" << g711Ogm << "/"" << endl;
g711Ogm = "";
}
}
if (g711Ogm.IsEmpty())
cout << "No G711 outgoing message set/n";
else {
cout << "Using /"" << g711Ogm << "/" as G.711 outgoing message/n";
}

// Check LPC10 OGM message
if (!lpc10Ogm.IsEmpty()) {
if ((g7231Ogm.Find("%s") == P_MAX_INDEX) && !PFile::Exists(lpc10Ogm)) {
cout << "warning: cannot open LPC10 OGM file /"" << lpc10Ogm << "/"" << endl;
lpc10Ogm = "";
}
}
if (lpc10Ogm.IsEmpty())
cout << "No LPC10 outgoing message set/n";
else {
cout << "Using /"" << lpc10Ogm << "/" as LPC10 outgoing message/n";
}

#ifdef SPEEX_CODEC
// Check Speex OGM message
if (!speexOgm.IsEmpty()) {
if ((g7231Ogm.Find("%s") == P_MAX_INDEX) && !PFile::Exists(speexOgm)) {
cout << "warning: cannot open Speex OGM file /"" << speexOgm << "/"" << endl;
speexOgm = "";
}
}
if (speexOgm.IsEmpty())
cout << "No Speex outgoing message set/n";
else {
cout << "Using /"" << speexOgm << "/" as Speex outgoing message/n";
}
#endif


if (g7231Ogm.IsEmpty() && gsmOgm.IsEmpty() && g711Ogm.IsEmpty()
&& lpc10Ogm.IsEmpty()
#ifdef SPEEX_CODEC
&& speexOgm.IsEmpty()
#endif
) {
cerr << "Must specify at least one outgoing message" << endl;
return FALSE;
}

if (!g7231Ogm.IsEmpty())
SetCapability(0, 0, new G7231_File_Capability);

if (!gsmOgm.IsEmpty())
SetCapability(0, 0, new H323_GSM0610Capability);

if (!gsmOgm.IsEmpty())
SetCapability(0, 0, new MicrosoftGSMAudioCapability);

//这是 AM Endpoint的能力 支持g711的alaw和ulaw
if (!g711Ogm.IsEmpty())
SetCapability(0, 0, new H323_G711Capability( H323_G711Capability::muLaw, H323_G711Capability::At64k));

if (!g711Ogm.IsEmpty())
SetCapability(0, 0, new H323_G711Capability( H323_G711Capability::ALaw, H323_G711Capability::At64k));

//没有用了
if (!lpc10Ogm.IsEmpty())
SetCapability(0, 0, new H323_LPC10Capability(*this));

#ifdef SPEEX_CODEC
if (!speexOgm.IsEmpty())
SetCapability(0, 0, new SpeexNarrow3AudioCapability());
#endif

capabilities.Remove(args.GetOptionString(D).Lines());
capabilities.Reorder(args.GetOptionString(P).Lines());

cout << "Codecs (in preference order):/n" << setprecision(2) << capabilities << endl;

return TRUE;
}

///////////////////////////////////////////////////////////////

//录音通道, 解码对象所附着的通道
//写文件
PCM_RecordFile::PCM_RecordFile(My H323Connection & _conn, const PFilePath & _fn, unsigned _callLimit)
: conn(_conn), fn(_fn), callLimit(_callLimit)
{
recordStarted = FALSE;
timeLimitExceeded = FALSE;
closed = FALSE;
dataWritten = FALSE;

// If the file name ends in .wav then open the output as a WAV file.
// Otherwise open it as a raw file.
if ((_fn.Right(4)).ToLower() == ".wav")
fileclass = new PWAVFile(_fn, PFile::WriteOnly,
PFile::ModeDefault,PWAVFile::PCM_WavFile);
else
fileclass = new PFile(_fn, PFile::WriteOnly);
}

void PCM_RecordFile::StartRecording()
{
PWaitAndSignal mutex(pcmrecordMutex);

if (recordStarted)
return;

PTRACE(1, "Starting recording to " << fn);

PTime now;
recordStarted = TRUE;
finishTime = now + (callLimit * 1000);
}

BOOL PCM_RecordFile::Close()
{
PWaitAndSignal mutex(pcmrecordMutex);

closed = TRUE;
return fileclass->Close();
}

BOOL PCM_RecordFile::Write(const void * buf, PINDEX len)
{
// Wait for the mutex, and Signal it at the end of this function
PWaitAndSignal mutex(pcmrecordMutex);

// If the record file has been closed, or if the time limit has
// been exceeded, then return immediatly.
if (closed || timeLimitExceeded)
return FALSE;

if (!recordStarted) {
DelayFrame(len);
return TRUE;
}

PTime now;
if ((callLimit != 0) && (now >= finishTime)) {
PTRACE(1, "Terminating call due to timeout");
conn.ClearCall();
timeLimitExceeded = TRUE;
return TRUE;
}

DelayFrame(len);

dataWritten = TRUE;

return WriteFrame(buf, len);
}

BOOL PCM_RecordFile::WriteFrame(const void * buf, PINDEX len)
{
//cerr << "Writing PCM " << len << endl;
return fileclass->Write(buf, len);
}

void PCM_RecordFile::DelayFrame(PINDEX len)
{
delay.Delay(len/16);
}

PCM_RecordFile::~PCM_RecordFile()
{
PWaitAndSignal mutex(pcmrecordMutex);

if (!dataWritten) {
PTRACE(1, "Deleting " << fn << " as no data recorded");
fileclass->Remove(fn);
}

delete fileclass;
}

///////////////////////////////////////////////////////////////
// Override some of the PCM_RecordFile functions to write
// G723.1 data instead of PCM data.

G7231_RecordFile::G7231_RecordFile(My H323Connection & _conn, const PFilePath & _fn, unsigned _callLimit)
: PCM_RecordFile(_conn, _fn, _callLimit)
{
// If the record file is a .wav file, we need to close the file
// that PCM_RecordFile will have opened, and reopen it as a G.723.1 Wav file.
if ((_fn.Right(4)).ToLower() == ".wav") {
fileclass->Remove(_fn);
delete fileclass;
fileclass = new PWAVFile(_fn, PFile::WriteOnly,
PFile::ModeDefault,PWAVFile::G7231_WavFile);
}
}

BOOL G7231_RecordFile::WriteFrame(const void * buf, PINDEX /*len*/)
{
int frameLen = G7231_File_Codec::GetFrameLen(*(BYTE *)buf);
// cerr << "Writing G7231 " << frameLen << endl;
return fileclass->Write(buf, frameLen);
}

void G7231_RecordFile::DelayFrame(PINDEX /*len*/)
{
// Ignore the len parameter as that is the compressed size.
// We must delay by the actual sample time.
delay.Delay((G7231_SAMPLES_PER_BLOCK*2)/16);
}

///////////////////////////////////////////////////////////////

static BOOL MatchString(const PString & str1, const PString str2)
{
if (str1.GetLength() != str2.GetLength())
return FALSE;

PINDEX len = str1.GetLength();

PINDEX i;
for (i = 0; i < len; i++)
if ((str1[i] != ?) && (str2[i] != ?) && (str1[i] != str2[i]))
return FALSE;

return TRUE;
}

static PINDEX FindMatch(const PStringList & list, const PString & key)
{
PINDEX maxKeyLen = 0;
PINDEX i;

PINDEX keyLen = key.GetLength();
PINDEX listLen = list.GetSize();

for (i = 0; i < listLen; i++)
maxKeyLen = PMAX(maxKeyLen, list[i].GetLength());

if (keyLen == 0 || maxKeyLen == 0)
return P_MAX_INDEX;

if (keyLen > maxKeyLen)
return P_MAX_INDEX;

PINDEX len = 1;
while (len <= keyLen) {
PString subStr = key.Left(len);

PINDEX matches = 0;
PINDEX lastMatch = P_MAX_INDEX;
PINDEX i;

// look for a match to the substring
for (i = 0; i < list.GetSize(); i++) {
if ((list[i].GetLength() >= keyLen) && MatchString(list[i].Left(len), subStr)) {
matches++;
lastMatch = i;
}
}

// if we got ONE match, we have a winner
if (matches == 1)
return lastMatch+1;

// if we have no matches, then there is no point continuing
if (matches == 0)
return P_MAX_INDEX;

// if we have more than one match, try the next char
len++;
}

// too many matches
return 0;
}


My H323Connection::My H323Connection(My H323EndPoint & _ep, unsigned callReference)
: H323Connection(_ep, callReference), ep(_ep)
{
basename = psprintf("%04i%02i%02i_%02i%02i%02i", callStartTime.GetYear(), callStartTime.GetMonth(), callStartTime.GetDay(),
callStartTime.GetHour(), callStartTime.GetMinute(), callStartTime.GetSecond());
recordFile = NULL;
ogmChannel = NULL;

receiveCodecName = transmitCodecName = "none";

cout << "Opening connection" << endl;

currentMenu = 0;
digits = "";

PConfig config;
PStringList sections = config.GetSections();
PINDEX i;
for (i = 0; i < sections.GetSize(); i++) {
if (sections[i].Find(MENU_PREFIX) == 0)
menuNames.AppendString(sections[i]);
}

}

My H323Connection::~My H323Connection()
{
cout << "Closing connection" << endl;

PTime now;
PTimeInterval interval = now - recordStartTime;
PString addr = GetControlChannel().GetRemoteAddress();

PString codecStr = receiveCodecName + "/" + transmitCodecName;
unsigned duration = (unsigned)((interval.GetMilliSeconds()+999)/1000);

LogCall(recordFn, addr, GetRemotePartyName(), duration, codecStr, product);

if ((recordFile!= NULL) && (recordFile->WasRecordStarted()) && !ep.GetRunCmd().IsEmpty()) {
PString cmdStr = ep.GetRunCmd() &
recordFn &
"/" + addr + "/" &
"/"" + GetRemotePartyName() + "/"" &
PString(PString::Unsigned, duration) &
"/"" + codecStr + "/"" &
"/"" + product + "/"";
PTRACE(1, "Executing : " << cmdStr);
system((const char *)cmdStr);
} else {
PTRACE(1, "No action to perform at end of record");
}

if (ogmChannel != NULL)
delete ogmChannel;

if (recordFile != NULL)
delete recordFile;

if (ep.GetDeleteAfterRecord()) {
PTRACE(1, "Removing " << recordFn << " as requested by option");
PFile::Remove(recordFn);
}
}

H323Connection::AnswerCallResponse
My H323Connection::OnAnswerCall(const PString & caller,
const H323SignalPDU & setupPDU,
H323SignalPDU & /*connectPDU*/)
{
product = "Unknown";

const H225_Setup_UUIE & setup = setupPDU.m_ h323_uu_pdu.m_ h323_message_body;
const H225_EndpointType & epInfo = setup.m_sourceInfo;

if (epInfo.HasOptionalField(H225_EndpointType::e_vendor)) {
const H225_VendorIdentifier & vendorInfo = epInfo.m_vendor;
if (vendorInfo.HasOptionalField(H225_VendorIdentifier::e_productId))
product = vendorInfo.m_productId.AsString();
if (vendorInfo.HasOptionalField(H225_VendorIdentifier::e_versionId))
product = product + "/" + vendorInfo.m_versionId.AsString();
}

cout << "Accepting call from " << caller << " using " << product << endl;

return AnswerCallNow;
}
//
//关键的东西都在这里
// 从传入的codec的的类别来判断 H323 Endpoint正在使用什么样的codec进行数据的编码解码
//显然我们一开始的设定影响了现在的codec, 我们设定 H323 Endpoint 的能力是G711,
// 所以这里应该是IsDescendant from H323_muLawCodec::Class() 或者 H323_ALawCodec::Class().
//
BOOL My H323Connection::OpenAudioChannel(BOOL isEncoding,
unsigned /* bufferSize */,
H323AudioCodec & codec)
{
codec.SetSilenceDetectionMode( H323AudioCodec::NoSilenceDetection);
PStringStream codecName;
codecName << codec;

PString ogm;
BOOL isPCM = FALSE;

if (codec.IsDescendant(G7231_File_Codec::Class())) {
ogm = ep.GetG7231OGM();
isPCM = FALSE;
} else if (codec.IsDescendant( H323_GSM0610Codec::Class())) {
ogm = ep.GetGSMOGM();
isPCM = TRUE;
} else if (codec.IsDescendant(MicrosoftGSMCodec::Class())) {
ogm = ep.GetGSMOGM();
isPCM = TRUE;
} else if (codec.IsDescendant( H323_muLawCodec::Class())) {
ogm = ep.GetG711OGM();
isPCM = TRUE;
} else if (codec.IsDescendant( H323_ALawCodec::Class())) {
ogm = ep.GetG711OGM();
isPCM = TRUE;
} else if (codec.IsDescendant( H323_LPC10Codec::Class())) {
ogm = ep.GetLPC10OGM();
isPCM = TRUE;
#ifdef SPEEX_CODEC
} else if (codec.IsDescendant(SpeexCodec::Class())) {
ogm = ep.GetSPEEXOGM();
isPCM = TRUE;
#endif
} else {
cerr << "Unknown codec /"" << codecName << endl;
return FALSE;
}


PWaitAndSignal mutex(connMutex);

if ((recordFile == NULL) && (isEncoding == FALSE)) {
if (isPCM) {
if (ep.GetRecordWav() == TRUE)
recordFn = ep.GetDirectory() + (basename + ".wav");
else
recordFn = ep.GetDirectory() + (basename + ".sw");
recordFile = new PCM_RecordFile (*this, recordFn, ep.GetCallLimit());
} else {
if (ep.GetRecordWav() == TRUE)
recordFn = ep.GetDirectory() + (basename + ".wav");
else
recordFn = ep.GetDirectory() + (basename + ".g723");
recordFile = new G7231_RecordFile(*this, recordFn, ep.GetCallLimit());
}
}

// 这里创建了我们想用的通道
if ((ogmChannel == NULL) && (isEncoding == TRUE)) {
if (isPCM)
ogmChannel = new PCM_OGMChannel(*this);
else
ogmChannel = new G7231_OGMChannel(*this);
}

if (isEncoding) {

if (ep.GetHangupAfterPlay())
ogmChannel->SetPlayOnce();

if (ogm.Find("%s"))
ogm.Replace("%s", e164Number);

transmitCodecName = codecName;
if (!StartMenu(0)) {
if (!PFile::Exists(ogm))
cerr << "error: cannot find OGM /"" << ogm << "/"" << endl;
else
ogmChannel->QueueFile(ogm);
if (!ep.GetNoRecordG7231())
ogmChannel->SetRecordTrigger();
}

//这里讲通道附着在codec上, 放音
codec.AttachChannel(ogmChannel, FALSE);
} else {
receiveCodecName = codecName;
//这里讲通道附着在codec上. 录音
codec.AttachChannel(recordFile, FALSE);
}
return TRUE;
}

BOOL My H323Connection::OnStartLogicalChannel( H323Channel & channel)
{
if (! H323Connection::OnStartLogicalChannel(channel))
return FALSE;

cout << "Started logical channel: ";

switch (channel.GetDirection()) {
case H323Channel::IsT