• [[Main.BuildingOpal]Building OPAL]

• Building PTLib
• [[http://wiki.opalvoip.org/index.php?n=Main.BuildingOpal]Building OPAL]

The |Opal FAQ is available as part of the Wiki at http://wiki.opalvoip.org.

Send any suggestions by email to the appropriate Opal mailing list. See the Wiki page for more information.

The openh323.org web site is not maintained by anybody. Please don't email us it.

The latest development plans and milestones can be found here

OpenMCU was originally created in May 2000 by Craig Southeren as an experiment to investigate some ideas about how an audio MCU might work. A description of the original motivations can be found at http://www.southeren.com/blog/archives/000050.html.

Please read the Wiki for more information on downloading from the Subversion repository.

The Subversion repository is hosted by SourceForge. See the Wiki for more detailed instructions.

You must make sure the patches are against a reasonably late version of the source. Do an SVN update immediately before creating the patches, as if it is too old it will not apply properly. Also do not send whole source files, they are even harder to deal with and SVN can produce diffs quite easily. Finally, please make sure they follow the coding standards!

Our time is at least as valuable as yours (more so really :-)) and if it gets too hard for us to apply your patch, it won't happen, and that does OPAL and the Open Source movement no good at all. It will make your life harder as you have to reapply your changes every time you get bug fixes from the SVN. So do the right thing!

If you have a code patch that adds a new feature or capability, or fixes a bug, then please submit it using the SourceForge patch tracker at http://sourceforge.net/tracker/?group_id=80674&atid=560614.

Make sure the two endpoints share a common codec.

7.15 - How many simultaneous calls can OPAL handle?

6.9 - Is there a document on the configure.exe program used for configuring OPAL and PTLib on Windows?

If you have a code patch that adds a new feature or capability, or fixes a bug, then please submit it using the SourceForge patch tracker at http://sourceforge.net/tracker/?group_id=80674&atid=560614, and please make sure it follows the coding standards!

The |Opal FAQ is available as part of the Wiki at http://www.opalvoip.org.wiki.

9.3 - When I enable PMEMORY_CHECK, I see all sorts of memory leaks reported. How do I fix these?

If you have a code patch that adds a new feature or capability, or fixes a bug, then please submit it using the SourceForge patch tracker at http://sourceforge.net/tracker/?group_id=80674&atid=560614

1.10 - Not used \\

4.2 - Microsoft Visual Studio will not load the DSP and DSW files provided with OpenH323 \\

4.4 - How do I cross compile OpenH323 for another platform?
4.5 - Are there detailed instructions for building OpenH323/PWLib on Windows?
4.6 - Can I compile OpenH323/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition? \\

4.9 - How do I fix the errors in vfakeio.cxx starting at line 411 like "newline in constant", "too many characters in constant", "syntax error: string"? \\

4.14 - How do I compile OpenH323 on Solaris? \\

4.18 - How do I stop my program from immediately crashing with a dialog saying "The application failed to initialise properly. Click on OK to terminate the application" when I use the DLL versions of PWLib and OpenH323, even though the statically linked versions work OK?
4.19 - How do I fix the following error on Windows when building PTLIB.DLL/OPENH323.DLL "dllmain.obj : fatal error LNK1202: "d:\pwlib.msvc\lib\ptlib.pdb" is missing debugging information for referencing module"?
4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. \ Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)"?
4.21 - I am compiling Pandora or Janus patch 4 - where is the ASNParser?
4.22 - Where is pwrc, openphone and all of GUI classes? \\

4.24 - The configure program for PWLib or OpenH323 is finding the wrong version of a library - how do I stop this?
4.25 - I used to be able to compile PWLib without any problems, but now I get warnings like this "Please remove pwlib\include\ptlib\msos from the tool include path and from the pre-processor options for this project" - how do I fix this? \\

4.27 - When I compile pwlib I get warnings like "../common/getdate.y: conflicts: 8 shift/reduce, 18 reduce/reduce" - is this normal?
4.28 - When I compile pwlib I get a warning like "In static member function `static std::ostream& PTrace::End(std::ostream&)':warning: unused variable 'rb'" - is this normal? \\

4.34 - How do I fix gcc errors about "PAtomicInteger" when compiling OpenH323 or OPAL?
4.35 - I cannot find the Console Components library files (ptclib.lib and ptclibd.lib) in recent builds of PWLib. Where are they?

5.1 - Why is there no G.723.1/G.729 codec in OPAL or OpenH323? \\

5.6 - How do I add my own audio or video codec to OPAL or OpenH323?
5.7 - What audio codecs are supported by OpenH323?
5.8 - What video codecs are supported by OpenH323? \\

5.16 - Does OpenH323 support wide-band codecs? \\

6.1 - Where can I get a design document for OpenH323? \\

6.3 - Where can I find user manuals for the Openh323 programs?
6.4 - Is there a programming tutorial for OpenH323? \\

6.6 - Where can I get documentation on the API for PWLib and OpenH323?
6.7 - What documentation is available for OpenH323? \\

6.9 - Is there a document on the configure.exe program used for configuring OpenH323 and PWLib on Windows?

7. USING OPAL and OPENH323

7.4 - How do I call NetMeeting with an OpenH323 client? \\

7.7 - I'm sure I have found a problem with OpenH323 - how do I report it? \\

7.10 - When I start OpenGK/OpenMCU2/OpenIVR as a windows service process it won't start due to "error 1053" or similar error. How do I fix this problem?
7.11 - How does OpenH323 support ENUM dialling? \\

7.15 - How many simultaneous calls can OPAL/OpenH323 handle?

8. OPAL and OpenH323 applications

8.1 - What other Open Source projects use OPAL and OpenH323?
8.2 - What commercial and closed-source software uses OPAL and OpenH323? \\

8.4 - How do I use OpenH323 with Asterisk?

9.1 - How do I create a program that uses OpenH323 for call control, but uses an external RTP device?
9.2 - How do get a list of the codecs supported by OpenH323? \\

10. OPAL

10.1 - What is OPAL?
10.2 - Where can I download OPAL?
10.3 - How do I compile OPAL? \\

10.5 - Is OpenH323 now obsolete or deprecated now that OPAL is released?
10.6 - Where can I find documentation on OPAL? \\

1.10 - Not used

The project continues to grow and mature thanks to the work of a dedicated group of developers. The following people have accepted the responsibility of CVS write access as well as the ability to close patch submissions, and can be considered to be the people responsible for leading OpenH323, OPAL and PWLib:

The owners of the openh323.org domain name (Quicknet Technologies, Inc) maintain the www.openh323.org web site and the openh323.org mailing list. See 1.4 for how to contact Quicknet.

I'm no longer associated with Quicknet, so I cannot make any changes to the openh323.org web site or mailing lists, even though I do have write access to the CVS (as do several other non-Quicknet people). I maintain a website with the latest information on OpenH323 and OPAL, and other projects at http://www.voxgratia.org

Run "./configure" for PWLib or OPAL with the appropriate flag to disable the module you want to avoid. Use "./configure --help" for a list of these flags.

4.6 - Can I compile OPAL/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition?

4.9 - How do I fix the errors in vfakeio.cxx starting at line 411 like "newline in constant", "too many characters in constant", "syntax error: string"?

This is a problem in older versions of PTLib, such as version 1.5.3. Download and use a later version of PWLib downloaded from SourceForge (see 3.1).

This error is usually caused by using source code that is incompatible with the version of PWLib that is being used. If you are using a version of PWLib prior to 1.7 (i.e. Janus or earlier), then IsDescendant function is available:

 obj.IsDescendant(MyParticularClass::Class())

In PWLib 1.7 and later, the function IsDescendant was replaced with PIsDescendant in order to provide support for C++ RTTI (Run Time Type Information). This function is used as follows:

 PIsDescendant(&obj, MyParticularClass)

4.14 - How do I compile OpenH323 on Solaris?

If you do not need to create trace files, you can half the size of the Unix binaries by ensuring that OpenH323 is compiled with the PASN_NOPRINTON and PASN_LEANANDMEAN symbols defined, and that everything is compiled without the PTRACING symbol

Also make sure to turn off features that you do not need, such as video. This can be done changing defines in the include/openh323buildopts.h file.

It is possible to get a Windows executable that includes video and audio with PWLib and OpenH323 linked statically, and dynamic links to everything else, in an .EXE that is under 1Mbyte (provided tracing is disabled)

There are several major defects in the STL header files shipped with MSVC 6. These defects are sufficient to crash programs (like PWLib) that rely on the correct behaviour of global static variables. Fortunately, the original authors of the STL libraries for MSVC have published new versions of the files necessary to correct the worst of these problems.

PWLib checks for the correct header file versions when a new compile is started, and will prevent the compile from continuing until the correct header files are installed. There is a "one-click" solution to this problem that will upgrade your files painlessly and quickly - see the following URL for more information: http://www.voxgratia.org/docs/pwlib_windows.html#msvc_headers or download the upgrade program from http://www.voxgratia.org/releases/msvc6chk.zip

4.18 - How do I stop my program from immediately crashing with a dialog saying "The application failed to initialise properly. Click on OK to terminate the application" when I use the DLL versions of PWLib and OpenH323, even though the statically linked versions work OK?

4.19 - How do I fix the following error on Windows when building PTLIB.DLL/OPENH323.DLL "dllmain.obj : fatal error LNK1202: "d:\pwlib.msvc\lib\ptlib.pdb" is missing debugging information for referencing module"?

This error seems to be a result of the linker getting confused about the debugging information in the pdb file. The only solution is to delete the entire pwlib/lib or openh323/lib directory and recompile everything again. You will have to exit MSVC before you can do this, as the environment keeps open files in that directory.

4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. \ Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)"?

If you are using PWLib 1.6/OpenH323 1.13 or earlier, then you need to compile the ASNParser. See http://www.voxgratia.org/docs/pwlib_windows.html#asnparser

4.21 - I am compiling Pandora or Janus patch 4 - where is the ASNParser?

The ASNParser is not included in the Pandora release, because it was decided to include the pre-processed ASN files directly into OpenH323. This greatly simplifies the build process for both PWLib and OpenH323 and removes the need for the ASNParser. The ASNParser is still available in the OpenH323 CVS, if you want to see it.

Janus patch 4 includes the ASNParser sources, but it does not need to be compiled or used as it this release has also been modified to include the pre-processed ASN files.

4.22 - Where is pwrc, openphone and all of GUI classes?

The time and effort and required to maintain the GUI code became unmanageable, especially when there are excellent multiple-platform GUI toolkits like Qt and wxWindows already available. As a result, the GUI code is no longer included in the baseline release archives. This includes the all of the source trees pwlib/src/pwlib, pwlib/include/ptlib, and the binaries pwlib.dll/pwlibd.dll/lib_pw_xxxx_r.so/lib_pw_xxxx_d.so

As always, the original source code is still available in the CVS but may not be actively maintained. See 3.10 for more information

4.24 - The Windows configure process for PWLib or OpenH323 is finding the wrong version of a library - how do I stop this?

4.25 - I used to be able to compile PWLib without any problems, but now I get warnings like this "Please remove pwlib\include\ptlib\msos from the tool include path and from the pre-processor options for this project" - how do I fix this?

Prior to the Janus release of OpenH323, it was necessary to include the "platform specific" include directory into the include paths for the environment. This requirement was removed because it was the source of many problems for users. The changes required to remove this dependency cause problems if the "platform specific" directory is retained, so the code has been altered to generate the above error if the include paths are not changed.

 In file included from /pwlib/include/ptlib/contain.h:782,
 from /pwlib/include/ptlib.h:146,

 /pwlib/include/ptlib/contain.inl: In constructor PAbstractList::PAbstractList()':
 /pwlib/include/ptlib/contain.inl:428: warning: right-hand operand of comma has no effect

4.27 - When I compile pwlib I get warnings like "../common/getdate.y: conflicts: 8 shift/reduce, 18 reduce/reduce" - is this normal?

4.28 - When I compile pwlib I get a warning like "In static member function `static std::ostream& PTrace::End(std::ostream&)': warning: unused variable 'rb'" - is this normal?

The long answer is that PWLib and OpenH323 attempt to preserve the ordinals used for DLL entry points across different versions of the libraries. To do this, the MergeSym program compares the function signatures in the DLLs to the entry points listed in the .dtf files, and makes sure that the final file ends up with compatible ordinals. The default .dtf files are created on a system with all optional features enabled, which means that if they are used on a system with less features, there are unresolved symbols left over.

4.30 - How do I link OpenH323, PWLib or OPAL applications statically in Windows?

4.31 - How do I link OpenH323, PWLib or OPAL applications statically on Unix?

4.34 - How do I fix gcc errors about "PAtomicInteger" when compiling OpenH323 or OPAL?

This error is usually indicates the presence of two incompatible versions of the pwlib headers, and that the openh323 build process is detecting the wrong set which is probably located in /usr/local/include or /usr/include (check the configure output to be sure)

The easiest way to solve the problem is to set the PWLIBDIR environment to point to the correct version of PWLib. Alternatively, deinstall the incorrect version so that the auto-detection find the correct version.

4.35 - I cannot find the Console Components library files (ptclib.lib and ptclibd.lib) in recent builds of PWLib. Where are they?

5.1 - Why is there no G.723.1/G.729 codec in OPAL or OpenH323?

As of 22 April 2004, the CVS head revision of OpenH323 contains the AliceStreet code that implements RFC 2190 compliant H.263 as required for compatibility with NetMeeting. As such, it is only available for users prepared to download and compile code from the CVS. This code will appear in future snapshots starting with PWLib 1.7.1 and OpenH323 1.14.1. See http://www.voxgratia.org/docs/h263_codec.html for more information.

The Janus release of OpenH323 and all versions up to PWLib 1.6.6.1/OpenH323 1.13.5.1 contain a non-compliant implementation of H.263 that is not compatible with NetMeeting.

For developers who need to use H.263 with earlier versions of OpenH323, patches are available from Guilhem Tardy at http://www.salyens.com/?page=ffcodec

5.6 - How do I add my own audio or video codec to Opal or OpenH323?

If you are using a current version of OPAL or OpenH323, then you have access to plugin codecs. See http://www.voxgratia.org/docs/codec_plugins.html for more information.

If you are using a version of OpenH323 prior to v1.14 or a version of OPAL prior to August 2006, then you will need to implement your codec as a embedded codec. Look at how other codecs such as GSM or H.261 are implemented for how to do this.

5.7 - What audio codecs are supported by OpenH323?

5.8 - What video codecs are supported by OpenH323?

Having said this, OpenH323 tries hard to get symmetric codecs but it is not always possible, especially if using slow start and the other end has a very different codec priority list.

There are two sets of Speex capabilities because the draft Speex RFC specified a format for the H.323 non-standard capability string that was incompatible with the format used by existing OpenH323 implementations. Thus, the only way to preserve backwards compatibility with old applications while still conforming to the new standard was to include both sets.

5.16 - Does OpenH323 support wide-band codecs?

6.1 - Where can I get a design document for OpenH323?

What design documents that do exist can be found at http://www.voxgratia.org/docs/openh323_design.html

6.3 - Where can I find user manuals for the Openh323 programs?

6.4 - Is there a programming tutorial on OpenH323?

Vladimir Toncar has written a tutorial that can be viewed at http://toncar.cz/openh323/tut/. It is available in English, Brazlilian Portuguese and Spanish

6.6 - Where can I get documentation on the API for PWLib and OpenH323?

The header files for OpenH323 and PWLib contain API documentation in the Doc++ format. The recommended tool for converting the header files into documents (as of 17 May 2004) is Doxygen (see http://www.doxygen.org) which is much faster and more accurate than the original Doc++ (see http://docpp.sourceforge.net).

To create the documentation for any particular version of PWLib or OpenH323, run the command "make docs" in the "pwlib" or "openh323" directories. A directory called "html" will be created that contains the documentation in HTML format. Doxygen can also be used to create documents in RTF and LaTex format, as well as the compressed HTML format (.CHM) for Windows.

Up to date versions of the API documentation can be found online at http://www.voxgratia.org/docs/pwlib? and http://www.voxgratia.org/docs/openh323?. Compressed archives of the documentation for various releases can be found on the Vox Gratia download page at http://www.voxgratia.org/downloads.html

6.7 - What documentation is available for OpenH323?

A list of all documentation available for OpenH323 can be found at http://www.voxgratia.org/documents.html

A map (i.e. a list sorted by topic) of all documentation available for OpenH323 can be found at http://www.voxgratia.org/docs/document_map.html

6.8 - Where can I find the specification documents for H.323?

6.9 - Is there a document on the configure.exe program used for configuring OpenH323 and PWLib on Windows?

7. USING OPENH323

Incoming calls require incoming connections on port 1720. Make sure that your firewall is passing incoming connections on that port to your client, and that your machine supports operation behind a firewall.

7.4 - How do I call NetMeeting with an OpenH323 client?

NetMeeting can inter-operate with an Open Source OpenH323 client using only a few audio and video codecs. These codecs are G.711 for audio and H.261 or H.263 for video.

The G.711 audio codec is available as an Open Source implementation and should be available on all OpenH323 endpoints that have audio enabled. It requires a 64 kbps connection and is only available in NetMeeting if it is configured for LAN bandwidth.

The H.261 video codec is available as an Open Source implementation should be available on all OpenH323 endpoints that have video enabled. The H.263 video codec, which used less bandwidth and provides better quality, may be available if the optional support has been enabled and the required external library is available.

• SpeexW - As of the Janus release, OpenH323 supports the SpeexW codec that can be added to NetMeeting. See http://www.republika.pl/roed/speexw/ for more information

NetMeeting contains proprietary codecs such as G.723.1 that may be available on some OpenH323 clients. For example, MyPhone (see http://myphone.sourceforge.net) contains code that allows use of the MS-ACM G.723.1 codec on a Windows client. See 5.4 for more informatio

7.7 - I'm sure I have found a problem with OpenH323 - how do I report it?

7.10 - When I start OpenGK/OpenMCU2/OpenIVR as a windows service process it won't start due to "error 1053" or similar. How do I fix this problem?

This error is caused by the service process being unable to start for some reason, usually because a required DLL cannot be found. To fix this problem, it is important to understand that all service processes are started with C:\WINDOWS\SYSTEM32 as the current directory regardless of the actual location of the executable, which means that all DLLs must be either in this directory or in some directory specified by the PATH environment variable.

The relocation of the current directory also affects the loading of PWLib plugins such as codecs, because the current directory is always included in the list of directories that are searched for plugins. By default, a program searches for plugins in the tree of subdirectories starting at the current directory when the program is started. This search involves looking at each DLL in turn, and checking to see if it is PWLib plugin.

Unfortunately, there was an error in older versions of PWLib that supported plugins which had the undesirable side effect of actually loading every DLL that was found, rather than loading only DLLs that are PWLib plugins. This bug meant that every DLL in C:\WINDOWS\SYSTEM32 (and there a lot of them) was loaded when a program was run as a Windows service. This usually resulted in a program crash with strange warnings about weird DLLs not being found, or at the very least causing the program to take an unusually long time to start up.

This problem was fixed in revision 1.16 of pwlib/include/ptlib/pluginmgr.h which is included in all Pandora releases after Pandora RC2. At this time, this patch is not included in any Janus releases.

7.11 - How does OpenH323 support ENUM dialling?

OpenH323 automatically implements ENUM dialling (RFC 2916) for endpoints under the following conditions:

OpenH323 and OPAL contain support for the STUN (Simple Traversal of UDP Through NAT) protocol to simplify making calls from behind a NAT firewall. This protocol uses a remote STUN server to assist a client in detecting what kind of NAT is being used.

Prior to 26 October 2004, the STUN client code in PWLib used a timeout of 500ms when waiting for results from the STUN server. This timeout was acceptable for most networks, but could result in incorrect results when used on busy or low speed connections, or on hosts that do not enjoy good connectivity to the Vox Gratia STUN server (stun.voxgratia.org).

The STUN client code now uses a timeout of 5000ms which gives reliable results, with the possible side effect of increasing setup time for hosts with busy or low speed connections.

To see determine what timeout is used by your code, find the file pwlib/src/ptclib/pstun.cxx and look for the following code near line 449:

 socket.SetReadTimeout(xxxx);

If xxxx is set to 500, then it is old code and the number must be changed to 5000. If this change is made, then recompile PWLib as required, and re-link any programs using OpenH323.

OpenH323 and PWLib support the STUN protocol (see RFC 3489) for detecting and interoperating with NATs and firewalls. The STUN protocol can detect several different NAT and firewall configurations, but only some of these configurations support VoIP functions. The detected NAT types are as follows:

Unfortunately, some endpoints do change the SSRC identifier mid-call and by default OpenH323 will detect the condition and ignore the new data. The warning message above will be displayed when this condition occurs.

If you need to interoperate with endpoints that change SSRC mid-call, you can disable the checking of SSRC identifiers by editing the file openh323/src/rtp.c. Look for a line of code in the function RTP_Session::RTP_Session as follows:

7.15 - How many simultaneous calls can OPAL/OpenH323 handle?

A more precise answer is that without any modification, a standard OPAL/OpenH323 application on Linux that handles both signalling and media will hit the per-process file handle limit at about 80 simultaneous calls. By increasing the per-process file handle limit to 16384 (using "ulimit") the maximum call density is around 1300 calls. If the calls always use H.245 tunnelling, this will increase to 110 and 1800. If the calls are signalling only, the limits are 330 and 5400.

An OpenH323 application can increase these limits further by enabling signalling aggregation. This feature is not yet available on OPAL.

8. OPAL and OpenH323 applications

8.1 - What other projects use OpenH323?

• CPhone - http://www.cphone.org
  Client program for Linux and Windows platforms based on OpenH323
• GnuGK - http://www.gnugk.org
  A gatekeeper for Unix and Windows based on OpenH323
• MyPhone - http://myphone.sourceforge.net
  Another client program based on OpenH323

Client program for MacOSX based on OpenH323

• OCX for OpenH323 - http://www.geocities.com/rddamian/
  An OCX control for OpenH323 that can be used in Visual Basic and MSIE. The page above seems to be out of date, but the latest sources can be found in the OpenH323 CVS in the contrib/DCOM directory.
• YATE - http://yate.null.ro/pmwiki/
  Yate is Yet Another Telephone Engine and uses OpenH323 for H.323 functionality
• Bayonne - http://www.gnu.org/software/bayonne/
  Bayonne is a telephony communications server that uses OpenH323 for H.323 functionality

8.2 What commercial and closed-source software uses Opal and OpenH323?

The following commercial software is known to use OPAL or OpenH323:

• PacPhone - http://www.pacphone.com
  A softphone based on OpenH323 that supports encryption and authentication

• Internet switchboard - http://www.quicknet.net
  ISB is a softphone based on OpenH323 that supports Quicknet's range of audio compression cards
• Marratech Manager - http://www.maratech.com
  A cross-platform video conferencing solution from Marratech AB in Sweden using OpenH323.

8.4 - How do I use OpenH323 with Asterisk?

There are three different modules that interface Asterisk and OpenH323:

• asterisk-oh323 by Michael Manousos - http://www.inaccessnetworks.com/projects/asterisk-oh323
  This channel driver module is compiled with OpenH323 and PWLib, and uses the low level audio interface of OpenH323. This driver uses the RTP stack and codecs within OpenH323.
• channel_h323 by Jeremy McNamara - included as part of the standard Asterisk source package
  This channel driver module is compiled with OpenH323 and PWLib, and uses the external RTP interface of OpenH323. This driver uses the RTP stack and codecs from Asterisk
• chan_woomera with Woomera by Anthony Minessale - www.pbxfreeware.org/chan_woomera
  This module uses a simple Asterisk channel driver called chan_woomera that does not contain any H.323 code. This driver communicates with a separate process called Woomera that contains OpenH323.

9.1 How do I create a program that uses OpenH323 for call control, but uses an external RTP device?

This is quite easy to do, and is explained in more detail at http://www.voxgratia.org/docs/external_rtp.html

9.2 - How do get a list of the codecs supported by OpenH323?

The static function H323PluginCodecManager::GetMediaFormats will return a list of all of the codecs that are supported by the current set of plugins and statically linked code without requiring any additional hardware. By default, this will include all of the audio codecs that can be converted to/from PCM-16. It will also include any video media formats that are supported by the stack. This will always include H.261 (if video is compiled into the stack) and H.263 (if support has been compiled and all necessary run-time loadable libraries are available).

The virtual function OpalLineInterfaceDevice::GetMediaFormats can be called on any instance of OpalLineInterfaceDevice or descendant to obtain the media formats supported by a specific hardware device.

See http://www.voxgratia.org/docs/codec_plugins.html for more information on the plugin codec system in OpenH323, including general information on codecs

There is a define called PMEMORY_CHECK that enabled all sorts of code in PWLib to check memory blocks allocated by the code. But this is turned off by default (even in debug mode) because the code it uses is pretty stupid. Not only does it slow down the entire stack by a significant amount, but it reports all sorts things as memory leaks when they really aren't. We got tired of people going into a panic when they saw the words "memory leak" and then having to explain why this was not a problem, so we just disabled it.

By this definition (which I agree with), a memory leak it is not just a memory block that is never freed, but it a problem with memory allocation that leads to memory exhaustion. This is an important distinction, because there are lots of places in PWLib, OpenH323 and OPAL where memory is allocated, but never freed, and these do not (and never will) lead to memory exhaustion because they are only allocated once and the reused for the lifetime of the program. The PFactory code is a good example of this.

10. OPAL

10.1 - What is OPAL?

OPAL is the "next generation" of OpenH323 that has a new architecture. Not only does it support H.323 and SIP, but new VoIP protocols or devices can be added very easily. It is being actively developed and is used by several projects such as Ekiga (http://www.ekiga.org)

BTW: OPAL is an acronym for Open Phone Abstraction Library, but that is not really important :)

10.2 - Where can I download OPAL?

OPAL sources in both tar.gz and ZIP formats can be downloaded from the Vox Gratia web site at http://www.voxgratia.org/downloads.html

OPAL can also be extracted from the OpenH323 CVS using "opal" module name

10.3 - How do I compile OPAL?

Compiling OPAL is very similar to compiling OpenH323. Detailed instructions on compiling OPAL under Windows can be found at http://www.voxgratia.org/docs/opal_windows.html

10.5 - Is OpenH323 now obsolete or deprecated now that OPAL is released?

For the foreseeable future, both OpenH323 and OPAL will continue to be maintained and updated. When we consider that OPAL has the same level of maturity and H.323 functionality as OpenH323, we will move OpenH323 into a maintenance-only mode. We're not sure when that will happen.

10.6 - Where can I find documentation on OPAL?

A reference document for the OPAL API can be extracted from the OPAL header files using the command "make docs". This command requires the Doxygen program. A copy of this documentation can be found at http://www.voxgratia.org/docs/opal

There is also a nice description of the OPAL architecture in a thesis written by Hadeel H. Taha titled "Architecture for a SIP-Based Conferencing Server". This document can be found at http://swt198.swt.fh-mannheim.de/gossip/download/Thesis_Taha.pdf and there is also a copy at http://www.voxgratia.org/docs/opal/Thesis_Taha.pdf.

A. Change log

2.15 - Why aren't there separate lists for users and developers like other projects? \\

4.11 - How do I fix errors about a missing function called PIsDescendant or IsDescendant ? \\

The official source code archives (tarballs and ZIP files) are available from the downloads page of the OpenH323 SourceForge project, which can be found at http://sourceforge.net/project/showfiles.php?group_id=80674. These same source archives (and occasionally some other releases) can also be found at the Vox Gratia web site at http://www.voxgratia.org/downloads.html. These releases are identical to those available on the SourceForge site as they are updated by the same maintainer from the official CVS repository.

Please do not use the sources from the download page on the official OpenH323 web site. These files have not been updated since 2003

The Ekiga (http://www.ekiga.org - formerly GnomeMeeting) team maintain up to date binary packages of OpenH323 and PWLib for Linux at http://www.gnomemeeting.org/index.php?rub=5&pos=0

Other (very out of date) binaries can be found on the OpenH323 site

The latest source code is always in the CVS (see 3.4 below), but the Ekiga team maintains very recent source code tarballs for Linux at http://snapshots.seconix.com and http://snapshots.voxgratia.org

If you are downloading from the repository, you have a number of versions to choose from:

3.4 - How do I access the CVS repository?

The CVS is hosted by SourceForge at cvs.sourceforge.net:/cvsroot/openh323. See http://www.voxgratia.org/docs/openh323_cvs.html for more detailed instructions. A web interface to the CVS can be found at http://openh323.cvs.sourceforge.net/openh323/

See 3.3 above for information on development tags available in the CVS, and 3.7 below on how to find a particular version of the source code.

ZIP files are now created for recent released, but may not be available for some older version. Windows users can use tar.gz source archives without any problems if an archive program that handles end of line characters and binaries is used. We recommend WinZIP. See section 4.2, 4.7 and 4.8 for related problems

Normally, the recommended stable version is the most recent version available from the SourceForge download page. The recommended versions are also shown on the Vox Gratia home page at http://www.voxgratia.org

If the version you require is not available on any of the download sites (see 3.1 above) then you will have to extract it from the CVS repository (see 3.4 above).

Every release of OpenH323 or PWLIB is available as a CVS tag. For example, version 1.6.0 or PWLib is assigned the tag v1_6_0. This is useful for doing compares between versions.

3.9 - What are Janus, Pandora, Mimas, Atlas and Phobos?

These names are all code names for various releases of OpenH323 or OPAL. A full explanation of all of the code names can be found on this page http://www.voxgratia.org/docs/milestones.html, but the important information is that the current stable releases are Phobos (for OPAL) and Atlas (for OpenH323). The current development builds are Deimos (for OPAL) and Titan (for OpenH323)

For those who are interested, the OpenH323 code names come from the moons of Saturn. The OPAL code names come from the two moons of Mars, which appropriately translate to Fear (Phobos) and Panic (Deimos). Future code names for OPAL will come from star names - the first one will be Centauri.

The configure.in files in PWLib and OpenH323 were renamed to configure.ac after the Pandora release as this is now the preferred extension for autoconf files. Unfortunately, the limitation of the CVS modules files do not allow for different file sets for different versions of the same module, which means that the configure.in files have been moved to the CVS "attic".

This means that extracting older releases of the source from the CVS by tag will not get the configure.in file. The file can be retreived using an explicit CVS checkout command to retrieve, as follows:

 cvs co -rPandora_release configure.in

We may be able to fix this problem at some time in the future - announcements will be made if this occurs

• Make sure that the pwlib directory is renamed to "pwlib" and the openh323 directory is "openh323", as the original tarball may have different names or your CVS client may have used the module name instead
• You need Bison and Flex installed as well as a compiler and associated tools. We recommend gcc and Make for Unix platforms, and Microsoft VS.net 2003 for Windows although other environments are supported. Note that the bison and flex package provided as part of the Windows build instructions (see 4.5) must be installed in C:\TOOLS unless you seriously know what you are doing.

4.2 - Microsoft Visual Studio will not load the DSP and DSW files provided with OpenH323

4.3 - I know the OpenLDAP/OpenSSL/Foobah library on my system is broken, but OpenH323 uses it anyway. How do I prevent this?

Run "./configure" for PWLib or OpenH323 with the appropriate flag to disable the module you want to avoid. Use "./configure --help" for a list of these flags.

4.4 - How do I cross compile OpenH323 for another platform?

4.5 - Are there detailed instructions for building OPAL, OpenH323 and PWLib on Windows?

Instructions for compiling OPAL, OpenH323 and PWLib on Windows can be found at http://www.voxgratia.org/docs/opal_windows.html, http://www.voxgratia.org/docs/pwlib_windows.html and http://www.voxgratia.org/docs/openh323_windows.html

4.6 - Can I compile OpenH323/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition?

Version 1.14 of OpenH323 and version 1.7 of PWLib and all later revisions contain full support for VS.NET 2003. See the build instructions (section 4.5 above) for full information in compiling in that environment.

Project files for VS.net 2005 and Visual C++ 2005 Express Edition were added on 26 June 2006 and are available in all later versions of the code. VC 5 Express Edition is available from:

http://msdn.microsoft.com/vstudio/express/visualc/download/

Louis Marascio has created a set of patches to allow compilation of earlier version of PWLib/OpenH323 with VS.net 2003. These can be downloaded from http://www.louismarascio.com/vsnet2003-openh323.zip

The file ptbuildopts.h is created from ptbuildopts.h.in by the pwlib/configure.exe program. If this step does not occur, then ptbuildopts.h is not created and the build process will fail. You need to determine why this is happening. See section 4.2 above or section 4.25 for a possible explanations

This indicates that the file pwlib/configure.exe program cannot be executed, probably because it is missing or corrupted. Download a new version and make sure it is a working Windows executable. See section 4.2 above for a possible explanation

This is a problem in older versions of PWLib, such as version 1.5.3. Download and use a later version of PWLib downloaded from SourceForge (see 3.1).

The best way to report a bug is to use the Bug tracker at the OpenH323 Source Forge site which can be found at http://sourceforge.net/tracker/?group_id=80674&atid=560612.

Sending an email to the OpenH323 mailing list will probably also work, but we would much rather you used the bug tracker.

4.11 - How do I fix errors about a missing function called PIsDescendant or IsDescendant ?

1.4 - Who owns and runs the OpenH323 mailing list and OpenH323 web site, and how do I contact them if I am having problems? \\

1.6 - I'm using pwlib 1.15.0 and openh323 1.5.2 from the openh323.org site, and I have a problem. Will anyone help me? \\

1.9 - What are the development plans for OpenH323 and OPAL?
1.10 - What were the H.323 security vulnerabilities reported by the NISCC, and how do they affect OpenH323? \\

1.12 - What is the license used for PWLib, OpenH323 and OPAL, and why wasn't the GPL used?
1.13 - What restrictions are placed on the software can I combine with PWLib, OpenH323 and OPAL?
1.14 - What license restrictions are placed on changes I make to PWLib, OpenH323 and OPAL?
1.15 - Where did PWLib, OpenH323 and OPAL come from, and who is responsible for it now?

2.4 - What is the mailing list used for? \\

2.16 - Can I ask questions about how to use/debug/understand another H.323 stack?

1.1 - Where can I find the FAQ?

The FAQ is available at http://www.voxgratia.org/docs/faq.html, and is posted automatically every two weeks to the OpenH323 mailing list. It also available in text form at http://www.voxgratia.org/docs/openh323-faq.txt

1.2 - My question is not answered by the FAQ, how can I make a suggestion?

Send any suggestions by email to craigs@postincrement.com

1.4 - Who owns and runs the OpenH323 mailing list and OpenH323 web site, and how do I contact them if I am having problems?

The OpenH323 mailing list is hosted by SourceForge and maintained by Quicknet Technologies. Problems regarding the operation of the list should be sent to Dave Erhart <daviderhart@sourforge.net>. See 2.1 and 2.3 for information on subscribing to the list.

Note that the previous mailing list at openh323@openh323.org went offline in March 2007.

It is well known that the openh323.org web site contains out-of-date information and a very old version of the code. Feel free to email Quicknet regarding this problem but please don't email the mailing list, or me, as there is nothing we can do about it.

1.6 - I'm using pwlib 1.12.0 and openh323 1.5.2 from the openh323.org site, and I have a problem. Will anyone help me?

It is very unlikely that anyone will assist you with problem in that version of the code, because it has not been updated since mid-2003. There have been several major stable releases of the system in that time, so you should upgrade to the latest stable build and see if your problem persists. If it still happens with more recent code, then ask again.

And yes, it is known that that the openh323.org only provides these old versions of the code. See 1.4 for more information

1.9 - What are the development plans for OpenH323 and OPAL?

The latest development plans and milestones can be found at http://www.voxgratia.org/docs/milestones.html?

1.10 - What were the H.323 security vulnerabilities reported by the NISCC, and how do they affect OpenH323?

The NISSC announced on 13 January 2004 that they had discovered vulnerabilities in several implementations of the H.323 protocol. This announcement was also released by CERT as Advisory CA-2004-01.

All releases of PWLib after v1.6.0 contain fixes for the vulnerabilities demonstrated by the NISCC test suite. This includes the Janus and Pandora baseline releases and all subsequent stable and development code releases.

For more information, see http://www.voxgratia.org/docs/niscc_006489-h323.html

A new project was started in March 2006 with the support of Stonevoice to restore video functionality to OpenMCU. This work is proceeding, and will result in a full-featured version of OpenMCU that supports video and audio.

1.12 - What is the license used for PWLib, OpenH323 and OPAL, and why wasn't the GPL used?

PWLib, OpenH323 and OPAL are available under v1.0 of the Mozilla Public License (MPL). The MPL was chosen specifically because it permits commercial software to be combined with OpenH323 and OPAL in ways that the GPL does not, but still requires changes to the released code to be contributed back to the community. The exact text of the license used for OpenH323 can be viewed in the CVS here.

1.13 - What restrictions are placed on the software can I combine with PWLib, OpenH323 and OPAL?

The MPL places no restrictions on what software you may combine with PWLib, OpenH323 or OPAL. You can use OpenH323 with closed source software or with Open Source software released under other licenses, provided that the other license allows this.

1.14 - What license restrictions are placed on changes I make to PWLib, OpenH323 and OPAL?

In plain language, this means that any changes you make to any existing OpenH323 source file must be released under the same MPL license. This same applies to any new file that contains part of any previously released code.

However, the MPL places no restrictions on any new files you create that contain wholly original code. You can choose to release (or not release) these files under any license you choose. Please note that files not covered by the MPL will not be included in the official OpenH323 CVS.

1.15 - Where did PWLib, OpenH323 and OPAL come from, and who is responsible for it now?

PWLib was started by in 1992 by Robert Jongbloed and Craig Southeren, and the copyright for the code was transferred to an Australian company called Equivalence Pty Ltd in 1996. Work commenced on OpenH323 in 1998, and PWLib and OpenH323 was released as Open Source software using the MPL license in the same year. The openh323.org domain name was acquired at this time, and the code was made available via a private server at that web address. OPAL coding started in late 1999 and was released under the same license.

Currently, the CVS remains hosted on SourceForge while the mailing list is hosted by a mail server run by Quicknet who retain the rights to the openh323.org domain name and the ownership of Equivalence Pty Ltd. There have been no new contributions to the codebase by Quicknet or updates to the openh323.org web site since June 2003.

Bruce Ferrell administers the mailing list and SourceForge web site on behalf of Quicknet.

2. USING THE OPENH323 LIST

2.1 - How do I subscribe to the mailing list?

The only way to subscribe is via the form on the following web page

https://lists.sourceforge.net/lists/listinfo/openh323-devel

The only way to unsubscribe is via the form at the bottom of the following web page

https://lists.sourceforge.net/lists/listinfo/openh323-devel

Send an email to openh323-devel@lists.sourceforge.net.

2.4 - What is the mailing list used for?

This list is used for asking any questions related to the OpenH323 project or related technologies.

• Questions unrelated to OpenH323

Yes. http://sourceforge.net/mailarchive/forum.php?forum=openh323-devel

Archives of the old list can be found at http://www.openh323.org/pipermail/openh323/

There are several enforcers who ensure that the rules are applied fairly and consistently. If you are emailed by Craig Southeren or David Erhart for being off-topic, for flaming, or if they indicate that an email thread is closed, it is suggested that you listen carefully unless you have kneecaps you no longer care about.

2.15 - Why aren't there separate lists for users and developers like other projects?

Feel free to subscribe to the lists on SourceForge as you please.

2.16 - Can I ask questions about how to use/debug/understand another H.323 stack?

The OpenH323 mailing list is intended for questions and issues related to the OpenH323 stack. If you have questions about a commercial H.323 stack, then you should contact the stack vendor for support. Commercial stacks are usually covered by non-disclosure agreements, so it's unlikely that anyone on the list could help you without breaking that agreement.

If you have questions regarding H.323 that are not related to OpenH323 or any other specific stack, then the Packetizer site (see http://www.packetizer.com has many excellent resources. It also has information on several H.323 mailing lists (see http://www.packetizer.com/voip/h323/lists.html)

simpleopal -n h323:h323.voxgratia.org

simpleopal -n sip:192.168.1.247

See 10.1

The owners of the openh323.org domain name (Quicknet Technologies, Inc) maintain the www.openh323.org web site and the openh323.org mailing list. See 1.4 ]]for how to contact Quicknet.

If you have a patch that adds a new feature, then please use the patch tracker as described in 4.16

See 7.8

See 7.9

See 4.10

4.8 - How do I fix the Windows build error "Configuring Build Options \ This program cannot run in DOS mode \ Error executing c:\windows\system32\cmd.exe" ? \\

4.12 - How do I fix errors about missing include files like "gsmcodec.h" or "lpc10codec.h" \\

4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. \ Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)" ? \\

8.2 - What other Open Source projects use OPAL and OpenH323? \\

The OpenH323 mailing list is hosted by SourceForge and maintained by Quicknet Technologies. Problems regarding the operation of the list should be sent to Dave Erhart <daviderhart@sourforge.net>. See 2.1 and 2.3 for information on subscribing to the lis

Note that the previous mailing list at openh323@openh323.org went offline in March 2007.

It is well known that the openh323.org web site contains out-of-date information and a very old version of the code. Feel free to email Quicknet regarding this problem but please don't email the mailing list, or me, as there is nothing we can do about it.

And yes, it is known that that the openh323.org only provides these old versions of the code. See 1.4 for more informati

The NISSC announced on 13 January 2004 that they had discovered vulnerabilities in several implementations of the H.323 protocol. This announcement was also released by CERT as Advisory CA-2004-01.

However, the MPL places no restrictions on any new files you create that contain wholly original code. You can choose to release (or not release) these files under any license you choose. Please note that files not covered by the MPL will not be included in the official OpenH323 CVS.

In early 2000, Robert and Craig sold Equivalence Pty Ltd and the rights to the openh323.org domain name to a US company called Quicknet Technologies Inc. They were also employed by Quicknet to support OpenH323 and to develop associated software. The OpenH323 CVS and mailing list was moved to a new server managed by Quicknet.

When you subscribe to the list, make sure you select "Yes" on the option labelled "Would you like to receive list mail batched in a daily digest?". If you are replying to messages contained in a digest, please make sure you change the subject line to reflect your question rather than retaining the arbitrary digest title.

No flaming. No trolls. Be nice. Be warned.

2.10 - How can I ensure someone will answer my question?

If you see a question for which you know the answer, or you see a reply that you know to be incorrect, then please join in the discussion. And be gracious if you make a mistake - being wrong is not a crime but being impolite certainly is.

2.16 - Can I ask questions about how to use/debug/understand another H.323 stack?

Please do not use the sources from the download page on the official OpenH323 web site. These files have not been updated since 2003

The latest source code is always in the CVS (see 3.4 below), but the Ekiga team maintains very recent source code tarballs for Linux at http://snapshots.seconix.com and [[http://snapshots.voxgratia.org|http://snapshots.voxgratia.org

This is always the very latest, up to the minute, source code. This may not work or even compile so use with caution||

See 3.7 below on how to find a particular version of the source code in the C

See 3.3 above for information on development tags available in the CVS, and 3.7 below on how to find a particular version of the source cod

If the version you require is not available on any of the download sites (see 3.1 above) then you will have to extract it from the CVS repository (see 3.4 above

Every release of OpenH323 or PWLIB is available as a CVS tag. For example, version 1.6.0 or PWLib is assigned the tag v1_6_0. This is useful for doing compares between versions.

The owners of the openh323.org domain name (Quicknet Technologies, Inc) maintain the www.openh323.org web site and the openh323.org mailing list. See 1.4 ]]for how to contact Quickne

For those who are interested, the OpenH323 code names come from the moons of Saturn. The OPAL code names come from the two moons of Mars, which appropriately translate to Fear (Phobos) and Panic (Deimos). Future code names for OPAL will come from star names - the first one will be Centauri.

• You need Bison and Flex installed as well as a compiler and associated tools. We recommend gcc and Make for Unix platforms, and Microsoft VS.net 2003 for Windows although other environments are supported. Note that the bison and flex package provided as part of the Windows build instructions (see 4.5) must be installed in C:\TOOLS unless you seriously know what you are doin

If you have this problem, you most likely will have the problems described in 4.7 and 4.8 as wel

The file ptbuildopts.h is created from ptbuildopts.h.in by the pwlib/configure.exe program. If this step does not occur, then ptbuildopts.h is not created and the build process will fail. You need to determine why this is happening. See section 4.2 above or section 4.25 for a possible explanatio

4.8 - How do I fix the Windows build error "Configuring Build Options \ This program cannot run in DOS mode Error executing c:\windows\system32\cmd.exe" ?

This indicates that the file pwlib/configure.exe program cannot be executed, probably because it is missing or corrupted. Download a new version and make sure it is a working Windows executable. See section 4.2 above for a possible explanati

This is a problem in older versions of PWLib, such as version 1.5.3. Download and use a later version of PWLib downloaded from SourceForge (see 3.1)

Sending an email to the OpenH323 mailing list will probably also work, but we would much rather you used the bug tracker.

 obj.IsDescendant(MyParticularClass::Class()) 

In PWLib 1.7 and later, the function IsDescendant was replaced with PIsDescendant in order to provide support for C++ RTTI (Run Time Type Information). This function is used as follows:

 PIsDescendant(&obj, MyParticularClass) 

These files were removed when support for audio codec plugins was introduced. See the document http://www.voxgratia.org/docs/codec_plugins.html#converting for more information

You need to install the GNU bison and flex programs program. See http://www.voxgratia.org/docs/pwlib_windows.html#flexbison for information on how to do this.

First of all, make sure you are using the Release build ("make opt" for Unix) and the "No Trace" build for Windows.

Linux executable is always larger that the comparable Windows program, but it possible to get the same code in under 3Mbytes.

If you have a code patch that adds a new feature or capability, or fixes a bug, then please submit it using the SourceForge patch tracker at http://sourceforge.net/tracker/?group_id=80674&atid=560614

4.17 - How do I fix the following error on when compiling using MSVC 6 "WARNING: the following file requires upgrading: C:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\XTREE \ Please run 'msvc6chk upgrade' to upgrade this file"?

This is probably because you have not upgraded your MSVC 6 header files - see 4.17 abo

4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)" ?

As always, the original source code is still available in the CVS but may not be actively maintained. See 3.10 for more informatio

For more information on Jim Clark's excellent XML toolkit, see http://www.jclark.com/xml/expat.html or http://expat.sourceforge.net

To fix this, it is necessary to tell configure not to search in certain directories for files. This can be done by changing the configure command line in the project file, but there are also several predefined environment variables which, if set, will be used by configure to determine which directories to ignore. These variables are set to a list of directories separated by semicolons (";") :

These errors are probably due some flag differences in the bison pre-processor, but the solution is very simple. Simply upgrade your code to at least the last Janus release version (as of 1 Nov 2004, this was Janus patch 4) because that version (and all subsequent versions) no longer require the ASN parser to be compiled. See 4.21 for more informati

The long answer is that PWLib and OpenH323 attempt to preserve the ordinals used for DLL entry points across different versions of the libraries. To do this, the MergeSym program compares the function signatures in the DLLs to the entry points listed in the .dtf files, and makes sure that the final file ends up with compatible ordinals. The default .dtf files are created on a system with all optional features enabled, which means that if they are used on a system with less features, there are unresolved symbols left over.

It is not clear whether this is legal or not, but there is reason to believe that usage of the MS G.723.1 codec by programs other than those authorised by Microsoft is in violation of the DMCA. We choose not to use this codec for that reason - you make your own choice.

As expected, the patent issue is not as clear.

In the end, there is no definitive answer saying that ffmpeg is safe to use, or not. You'll have to make up your own mind and get your own advice.

Vladimir Toncar has written a tutorial that can be viewed at http://toncar.cz/openh323/tut/. It is available in English, Brazlilian Portuguese and Spanish

You are probably behind a firewall and are trying to make a call to someone on the other side… See your software documentation for how to solve this problem

7.3 - I can establish a connection but no audio is transferred. What is wrong?

Make sure the two endpoints share a common codec.

7.5 - I hear an echo when I speaking on a H.323 call - what is wrong?

The echo is most likely caused by audio coming out the speaker being picked up by the microphone. Either move the speaker and microphone further apart, reduce the speaker volume, or (best of all) use a headset or handset.

7.6 - How can I test whether my client is working?

7.8 - Why am I getting bad audio even though I am using the G.711 codec?

• your machine is too busy, or has a congested network interface. Close down other network-based or sound-based applications on the same machine.

e164.voxgratia.net e164.org e164.arpa

OpenH323 and PWLib support the STUN protocol (see RFC 3489) for detecting and interoperating with NATs and firewalls. The STUN protocol can detect several different NAT and firewall configurations, but only some of these configurations support VoIP functions. The detected NAT types are as follows:

A more precise answer is that without any modification, a standard OPAL/OpenH323 application on Linux that handles both signalling and media will hit the per-process file handle limit at about 80 simultaneous calls. By increasing the per-process file handle limit to 16384 (using "ulimit") the maximum call density is around 1300 calls. If the calls always use H.245 tunnelling, this will increase to 110 and 1800. If the calls are signalling only, the limits are 330 and 5400.

An OCX control for OpenH323 that can be used in Visual Basic and MSIE. The page above seems to be out of date, but the latest sources can be found in the OpenH323 CVS in the contrib/DCOM directory.

The following commercial software is known to use OPAL or OpenH323:

A new project was started in March 2006 with the support of Stonevoice to restore video functionality to OpenMCU. In June 2006, OpenMCU 2.2.0 was released with full support for both audio and video including the H.261 and H.263 codecs.

It is these memory blocks that cause PMEMORY_CHECK to be a pain. It reports every one of these memory allocations as a memory leak even though they are not causing any problems. So why don't we just ensure that these memory blocks are cleaned up? Two reasons - firstly we don't have time to spend on issues that are not real problems; and secondly, it can be difficult to determine exactly when some of these memory blocks should actually be freed in order to avoid causing problems during shutdown. So we just choose to avoid the issue.

The following command makes a SIP call to a remote endpoint without using a registrar.

There is also a nice description of the OPAL architecture in a thesis written by Hadeel H. Taha titled "Architecture for a SIP-Based Conferencing Server". This document can be found at http://swt198.swt.fh-mannheim.de/gossip/download/Thesis_Taha.pdf and there is also a copy at http://www.voxgratia.org/docs/opal/Thesis_Taha.pdf

 -u userid -p \ 
 password \ \\

 simplopal -H -u userid --password password --register-sip proxy01.sipphone.com sip:number@proxy01.sipphone.com 

Updated 3.3 and 3.4 on CVS tags \\

ZIP files are now created for recent released, but may not be available for some older version. Windows users can use tar.gz source archives without any problems if an archive program that handles end of line characters and binaries is used. We recommend WinZIP. See section 4.2, 4.7 and 4.8 for related proble

ZIP files are now created for recent released, but may not be available for some older version. Windows users can use tar.gz source archives without any problems if an archive program that handles end of line characters and binaries is used. We recommend WinZIP. See section 4.2?, 4.7 and 4.8 for related proble

#Q#6_6

The OpenH323 mailing list is hosted by SourceForge and maintained by Quicknet Technologies. Problems regarding the operation of the list should be sent to Dave Erhart <daviderhart@sourforge.net>. See 2.1]] and 2.3 for information on subscribing to the lis

And yes, it is known that that the openh323.org only provides these old versions of the code. See 1.4]] for more informati

The latest source code is always in the CVS (see 3.4]] below), but the Ekiga team maintains very recent source code tarballs for Linux at http://snapshots.seconix.com and [[http://snapshots.voxgratia.org|http://snapshots.voxgratia.org

See 3.7]] below on how to find a particular version of the source code in the C

See 3.3]] above for information on development tags available in the CVS, and 3.7 below on how to find a particular version of the source cod

ZIP files are now created for recent released, but may not be available for some older version. Windows users can use tar.gz source archives without any problems if an archive program that handles end of line characters and binaries is used. We recommend WinZIP. See section 4.2]], 4.7 and 4.8 for related proble

If the version you require is not available on any of the download sites (see 3.1]] above) then you will have to extract it from the CVS repository (see 3.4 above

• You need Bison and Flex installed as well as a compiler and associated tools. We recommend gcc and Make for Unix platforms, and Microsoft VS.net 2003 for Windows although other environments are supported. Note that the bison and flex package provided as part of the Windows build instructions (see 4.5]]) must be installed in C:\TOOLS unless you seriously know what you are doin

If you have this problem, you most likely will have the problems described in 4.7]] and 4.8 as wel

The file ptbuildopts.h is created from ptbuildopts.h.in by the pwlib/configure.exe program. If this step does not occur, then ptbuildopts.h is not created and the build process will fail. You need to determine why this is happening. See section 4.2]] above or section 4.25 for a possible explanatio

This indicates that the file pwlib/configure.exe program cannot be executed, probably because it is missing or corrupted. Download a new version and make sure it is a working Windows executable. See section 4.2]] above for a possible explanati

This is a problem in older versions of PWLib, such as version 1.5.3. Download and use a later version of PWLib downloaded from SourceForge (see 3.1]])

If you are reporting a bug without a code patch, then please use the bug tracker as described in 4.10]]

This is probably because you have not upgraded your MSVC 6 header files - see 4.17]] abo

As always, the original source code is still available in the CVS but may not be actively maintained. See 3.10]] for more informatio

These errors are probably due some flag differences in the bison pre-processor, but the solution is very simple. Simply upgrade your code to at least the last Janus release version (as of 1 Nov 2004, this was Janus patch 4) because that version (and all subsequent versions) no longer require the ASN parser to be compiled. See 4.21]] for more informati

NetMeeting contains proprietary codecs such as G.723.1 that may be available on some OpenH323 clients. For example, MyPhone (see http://myphone.sourceforge.net) contains code that allows use of the MS-ACM G.723.1 codec on a Windows client. See 5.4]] for more informatio

1.1 - Where can I find the FAQ?
1.2 - My question is not answered by the FAQ, how can I make a suggestion?
1.3 - Who maintains the FAQ?
1.4 - Who owns and runs the OpenH323 mailing list and OpenH323 web site, and how do I contact them if I am having problems?
1.5 - The FAQ describes something that sounds like my problem, and it refers to a document that I don't really understand. I don't have time for all of this - can I just email someone or contact them via IM and get them to explain it all to me?
1.6 - I'm using pwlib 1.15.0 and openh323 1.5.2 from the openh323.org site, and I have a problem. Will anyone help me? \\

1.8 - What is OPAL?
1.9 - What are the development plans for OpenH323 and OPAL?
1.10 - What were the H.323 security vulnerabilities reported by the NISCC, and how do they affect OpenH323? \\

1.12 - What is the license used for PWLib, OpenH323 and OPAL, and why wasn't the GPL used?
1.13 - What restrictions are placed on the software can I combine with PWLib, OpenH323 and OPAL?
1.14 - What license restrictions are placed on changes I make to PWLib, OpenH323 and OPAL?
1.15 - Where did PWLib, OpenH323 and OPAL come from, and who is responsible for it now?

2.1 - How do I subscribe to the mailing list?
2.2 - How do I unsubscribe from the mailing list?
2.3 - How do I make a posting to the mailing list?
2.4 - What is the mailing list used for?
2.5 - What is the mailing list *not* used for?
2.6 - There is too much traffic on the mailing list. Is there a digest?
2.7 - Is there a searchable archive of the list available?
2.8 - Are there any rules?
2.9 - Who enforces the rules?
2.10 - How can I ensure someone will answer my question?
2.11 - But I really need an URGENT answer to my question?
2.12 - Who answers questions on the list?
2.13 - I want to help by answering questions? How do I do this?
2.14 - Not used
2.15 - Why aren't there separate lists for users and developers like other projects?
2.16 - Can I ask questions about how to use/debug/understand another H.323 stack?

3.1 - Where can I download source code from?
3.2 - Where can I download binaries from?
3.3 - Where can I get the very latest source code from?
3.4 - How do I access the CVS repository?
3.5 - Where can I get ZIP versions of the source archives?
3.6 - How do I know what version to download?
3.7 - Where can I download a particular version of the code?
3.8 - Why isn't the latest code and information on openh323.org, and why don't you do something about it?
3.9 - What are Janus, Pandora, Mimas, Atlas and Phobos?
3.10 - Where can I download the old PWLib GUI code
3.11 - Why is the configure.in file is missing when I extract source code from the CVS?

4.1 - The code does not compile - what is the problem?
4.2 - Microsoft Visual Studio will not load the DSP and DSW files provided with OpenH323
4.3 - I know the OpenLDAP/OpenSSL/Foobah library on my system is broken, but OpenH323 uses it anyway. How do I prevent this?
4.4 - How do I cross compile OpenH323 for another platform?
4.5 - Are there detailed instructions for building OpenH323/PWLib on Windows?
4.6 - Can I compile OpenH323/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition?
4.7 - How do I fix the Windows build error "Cannot open include file: 'ptbuildopts.h': No such file or directory"?
4.8 - How do I fix the Windows build error "Configuring Build Options \ This program cannot run in DOS mode \ Error executing c:\windows\system32\cmd.exe" ?
4.9 - How do I fix the errors in vfakeio.cxx starting at line 411 like "newline in constant", "too many characters in constant", "syntax error: string"?
4.10 - How do I report a bug in the code?
4.11 - How do I fix errors about a missing function called PIsDescendant or IsDescendant ?
4.12 - How do I fix errors about missing include files like "gsmcodec.h" or "lpc10codec.h"
4.13 - How do I fix errors like "Cannot open source file: getdate_tab.c': No such file or directory"?
4.14 - How do I compile OpenH323 on Solaris?
4.15 - How do I make the code smaller?
4.16 - How do I submit patches to the code?
4.17 - How do I fix the following error on when compiling using MSVC 6 "WARNING: the following file requires upgrading: \ C:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\XTREE \ Please run 'msvc6chk upgrade' to upgrade this file"?
4.18 - How do I stop my program from immediately crashing with a dialog saying "The application failed to initialise properly. Click on OK to terminate the application" when I use the DLL versions of PWLib and OpenH323, even though the statically linked versions work OK?
4.19 - How do I fix the following error on Windows when building PTLIB.DLL/OPENH323.DLL "dllmain.obj : fatal error LNK1202: "d:\pwlib.msvc\lib\ptlib.pdb" is missing debugging information for referencing module"?
4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. \ Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)" ?
4.21 - I am compiling Pandora or Janus patch 4 - where is the ASNParser?
4.22 - Where is pwrc, openphone and all of GUI classes?
4.23 - How do I fix warnings about PVXMLSession and OpalVXMLSession not found compiling the opennivr/vxmltest/woomera programs?
4.24 - The configure program for PWLib or OpenH323 is finding the wrong version of a library - how do I stop this?
4.25 - I used to be able to compile PWLib without any problems, but now I get warnings like this "Please remove pwlib\include\ptlib\msos from the tool include path and from the pre-processor options for this project" - how do I fix this?
4.26 - How do I fix errors compiling asn_grammar.y/asn_grammar.cxx?
4.27 - When I compile pwlib I get warnings like "../common/getdate.y: conflicts: 8 shift/reduce, 18 reduce/reduce" - is this normal?
4.28 - When I compile pwlib I get a warning like "In static member function `static std::ostream& PTrace::End(std::ostream&)':warning: unused variable 'rb'" - is this normal?
4.29 - How do I fix link errors about missing functions when compiling DLLs on Windows?
4.30 - How do I link applications statically in Windows?
4.31 - How do I link applications statically on Unix?
4.32 - How do I stop configure from finding the wrong header files on Windows?
4.33 - How do fix errors about missing MSVC80.DLL or MSVCR80.DLL files when debugging using Visual C++ 2005 Express Edition?
4.34 - How do I fix gcc errors about "PAtomicInteger" when compiling OpenH323 or OPAL?
4.35 - I cannot find the Console Components library files (ptclib.lib and ptclibd.lib) in recent builds of PWLib. Where are they?

5.1 - Why is there no G.723.1/G.729 codec in OPAL or OpenH323?
5.2 - Can I use the ITU reference code for G.723.1 and G.729?
5.3 - Where can I get licensed G.723.1 and G.729 codec implementations?
5.4 - Can I use the Microsoft G.723.1 codec in my Windows program?
5.5 - How do I use the H.263 video codec with NetMeeting?
5.6 - How do I add my own audio or video codec to OPAL or OpenH323?
5.7 - What audio codecs are supported by OpenH323?
5.8 - What video codecs are supported by OpenH323?
5.9 - Where can I get more information on plugin codecs?
5.10 - Why does a call using a compressed audio codec use much more bandwidth than expected?
5.11 - What is the effect of changing the number of frames per packet for an audio codec?
5.12 - Why am I getting bad audio quality even though I am using G.711?
5.13 - Why am I getting bad audio when using the G.729 codec?
5.14 - How do I get the same codec in each direction when making a call?
5.15 - Why are there so many Speex capabilities?
5.16 - Does OpenH323 support wide-band codecs?
5.17 - Can I use the H.263 video codec in my program?

6.1 - Where can I get a design document for OpenH323?
6.2 - Where can I find the help file for OpenPhone?
6.3 - Where can I find user manuals for the Openh323 programs?
6.4 - Is there a programming tutorial for OpenH323?
6.5 - Is there documentation on audio codec plugins?
6.6 - Where can I get documentation on the API for PWLib and OpenH323?
6.7 - What documentation is available for OpenH323?
6.8 - Where can I find the specification documents for H.323?
6.9 - Is there a document on the configure.exe program used for configuring OpenH323 and PWLib on Windows?

7.1 - When I make a call I get audio in only one direction. What is the problem?
7.2 - I am behind a firewall and cannot receive incoming calls? Why not?
7.3 - I can establish a connection but no audio is transferred. What is wrong?
7.4 - How do I call NetMeeting with an OpenH323 client?
7.5 - I hear an echo when I speaking on a H.323 call - what is wrong?
7.6 - How can I test whether my client is working?
7.7 - I'm sure I have found a problem with OpenH323 - how do I report it?
7.8 - Why am I getting bad audio even though I am using the G.711 codec?
7.9 - Why am I getting bad audio when using the G.729 codec
7.10 - When I start OpenGK/OpenMCU2/OpenIVR as a windows service process it won't start due to "error 1053" or similar error. How do I fix this problem?
7.11 - How does OpenH323 support ENUM dialling?
7.12 - I am getting "Blocked" or other incorrect results when using STUN - how do I fix this?
7.13 - What are the different firewall types reported by STUN, and what do they mean?
7.14 - Why I am seeing messages like "RTP Packet from SSRC=xxxxxxxx ignored, expecting SSRC=yyyyyyyy" with audio only in one direction?
7.15 - How many simultaneous calls can OPAL/OpenH323 handle?

8.2 - What other Open Source projects use OPAL and OpenH323?
8.2 - What commercial and closed-source software uses OPAL and OpenH323?
8.3 - What is the status of the OpenMCU program?
8.4 - How do I use OpenH323 with Asterisk?

9.1 - How do I create a program that uses OpenH323 for call control, but uses an external RTP device?
9.2 - How do get a list of the codecs supported by OpenH323?
9.3 - When I enable PMEMORY_CHECK, I see all sorts of memory leaks reported. How do I fix these?

10.1 - What is OPAL?
10.2 - Where can I download OPAL?
10.3 - How do I compile OPAL?
10.4 - How do I use SimpleOPAL to make a call?
10.5 - Is OpenH323 now obsolete or deprecated now that OPAL is released?
10.6 - Where can I find documentation on OPAL?
10.7 - How do I use OPAL to make a call to a telephone number?

1. GENERAL

1.1 - Where can I find the FAQ?

1.2 - My question is not answered by the FAQ, how can I make a suggestion?

1.3 - Who maintains the FAQ?

1.4 - Who owns and runs the OpenH323 mailing list and OpenH323 web site, and how do I contact them if I am having problems?

The OpenH323 mailing list is hosted by SourceForge and maintained by Quicknet Technologies. Problems regarding the operation of the list should be sent to Dave Erhart <daviderhart@sourforge.net>. See 2.1 and 2.3 for information on subscribing to the list.

1.5 - The FAQ describes something that sounds like my problem, and it refers to a document that I don't really understand. I don't have time for all of this - can I just email someone or contact them via IM and get them to explain it all to me?

1.6 - I'm using pwlib 1.12.0 and openh323 1.5.2 from the openh323.org site, and I have a problem. Will anyone help me?

And yes, it is known that that the openh323.org only provides these old versions of the code. See 1.4 for more information

1.7 - Not used

1.8 - What is OPAL?

See 10.1

1.9 - What are the development plans for OpenH323 and OPAL?

1.10 - What were the H.323 security vulnerabilities reported by the NISCC, and how do they affect OpenH323?

1.11 - What is the status of the OpenMCU program?

1.12 - What is the license used for PWLib, OpenH323 and OPAL, and why wasn't the GPL used?

1.13 - What restrictions are placed on the software can I combine with PWLib, OpenH323 and OPAL?

1.14 - What license restrictions are placed on changes I make to PWLib, OpenH323 and OPAL?

1.15 - Where did PWLib, OpenH323 and OPAL come from, and who is responsible for it now?

2. USING THE OPENH323 LIST

2.1 - How do I subscribe to the mailing list?

2.2 - How do I unsubscribe from the mailing list?

2.3 - How do I make a posting to the mailing list?

2.4 - What is the mailing list used for?

2.5 - What is the mailing list *not* used for?

2.6 - There is too much traffic on the mailing list. Is there a digest?

2.7 - Is there an searchable archive of the list available?

2.8 - Are there any rules?

2.9 - Who enforces the rules?

2.10 - How can I ensure someone will answer my question?

2.11 - But I really need an URGENT answer to my question?

2.12 - Who answers questions on the list?

2.13 - I want to help by answering questions? How do I do this?

2.14 - Not used

2.15 - Why aren't there separate lists for users and developers like other projects?

2.16 - Can I ask questions about how to use/debug/understand another H.323 stack?

3. DOWNLOADING CODE

3.1 - Where can I download source code from?

3.2 - Where can I download binaries from?

3.3 - Where can I get the very latest source code from?

The latest source code is always in the CVS (see 3.4 below), but the Ekiga team maintains very recent source code tarballs for Linux at http://snapshots.seconix.com and http://snapshots.voxgratia.org

See 3.7 below on how to find a particular version of the source code in the CVS

3.4 - How do I access the CVS repository?

See 3.3 above for information on development tags available in the CVS, and 3.7 below on how to find a particular version of the source code.

3.5 - Where can I get ZIP versions of the source archives

ZIP files are now created for recent released, but may not be available for some older version. Windows users can use tar.gz source archives without any problems if an archive program that handles end of line characters and binaries is used. We recommend WinZIP. See section 4.2, 4.7 and 4.8 for related problems

3.6 - How do I know what version to download?

3.7 - Where can I download a particular version of the code?

If the version you require is not available on any of the download sites (see 3.1 above) then you will have to extract it from the CVS repository (see 3.4 above).

3.8 - Why isn't the latest code and information on openh323.org, and why don't you do something about it?

The owners of the openh323.org domain name (Quicknet Technologies, Inc) maintain the www.openh323.org web site and the openh323.org mailing list. See 1.4for how to contact Quicknet.

3.9 - What are Janus, Pandora, Mimas, Atlas and Phobos?

3.10 - Where can I download the old PWLib GUI code?

3.11 - Why is the configure.in file is missing when I extract source code from the CVS?

4. COMPILING THE CODE

4.1 - The code does not compile - what is the problem?

• You need Bison and Flex installed as well as a compiler and associated tools. We recommend gcc and Make for Unix platforms, and Microsoft VS.net 2003 for Windows although other environments are supported. Note that the bison and flex package provided as part of the Windows build instructions (see 4.5) must be installed in C:\TOOLS unless you seriously know what you are doing.

4.2 - Microsoft Visual Studio will not load the DSP and DSW files provided with OpenH323

If you have this problem, you most likely will have the problems described in 4.7 and 4.8 as well.

4.3 - I know the OpenLDAP/OpenSSL/Foobah library on my system is broken, but OpenH323 uses it anyway. How do I prevent this?

4.4 - How do I cross compile OpenH323 for another platform?

4.5 - Are there detailed instructions for building OPAL, OpenH323 and PWLib on Windows?

4.6 - Can I compile OpenH323/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition?

4.7 - How do I fix the Windows build error "Cannot open include file: 'ptbuildopts.h': No such file or directory"?

The file ptbuildopts.h is created from ptbuildopts.h.in by the pwlib/configure.exe program. If this step does not occur, then ptbuildopts.h is not created and the build process will fail. You need to determine why this is happening. See section 4.2 above or section 4.25 for a possible explanations

4.8 - How do I fix the Windows build error "Configuring Build Options \ This program cannot run in DOS mode Error executing c:\windows\system32\cmd.exe" ?

This indicates that the file pwlib/configure.exe program cannot be executed, probably because it is missing or corrupted. Download a new version and make sure it is a working Windows executable. See section 4.2 above for a possible explanation

4.9 - How do I fix the errors in vfakeio.cxx starting at line 411 like "newline in constant", "too many characters in constant", "syntax error: string"?

This is a problem in older versions of PWLib, such as version 1.5.3. Download and use a later version of PWLib downloaded from SourceForge (see 3.1).

4.10 - How do I report a bug in the code?

If you have a patch that adds a new feature, then please use the patch tracker as described in 4.16

4.11 - How do I fix errors about a missing function called PIsDescendant or IsDescendant ?

4.12 - How do I fix errors about missing include files like "gsmcodec.h" or "lpc10codec.h"?

4.13 - How do I fix errors like "Cannot open source file: getdate_tab.c': No such file or directory"?

4.14 - How do I compile OpenH323 on Solaris?

4.15 - How do I make the code smaller?

4.16 - How do I submit patches to the code?

If you are reporting a bug without a code patch, then please use the bug tracker as described in 4.10

4.17 - How do I fix the following error on when compiling using MSVC 6 "WARNING: the following file requires upgrading: C:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\XTREE \ Please run 'msvc6chk upgrade' to upgrade this file"?

4.18 - How do I stop my program from immediately crashing with a dialog saying "The application failed to initialise properly. Click on OK to terminate the application" when I use the DLL versions of PWLib and OpenH323, even though the statically linked versions work OK?

This is probably because you have not upgraded your MSVC 6 header files - see 4.17 above

4.19 - How do I fix the following error on Windows when building PTLIB.DLL/OPENH323.DLL "dllmain.obj : fatal error LNK1202: "d:\pwlib.msvc\lib\ptlib.pdb" is missing debugging information for referencing module"?

4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)" ?

4.21 - I am compiling Pandora or Janus patch 4 - where is the ASNParser?

4.22 - Where is pwrc, openphone and all of GUI classes?

As always, the original source code is still available in the CVS but may not be actively maintained. See 3.10 for more information

4.23 - How do I fix warnings about PVXMLSession and OpalVXMLSession not found compiling the opennivr/vxmltest/woomera programs?

4.24 - The Windows configure process for PWLib or OpenH323 is finding the wrong version of a library - how do I stop this?

4.25 - I used to be able to compile PWLib without any problems, but now I get warnings like this "Please remove pwlib\include\ptlib\msos from the tool include path and from the pre-processor options for this project" - how do I fix this?

4.26 - How do I fix errors compiling asn_grammar.y/asn_grammar.cxx?

These errors are probably due some flag differences in the bison pre-processor, but the solution is very simple. Simply upgrade your code to at least the last Janus release version (as of 1 Nov 2004, this was Janus patch 4) because that version (and all subsequent versions) no longer require the ASN parser to be compiled. See 4.21 for more information

4.27 - When I compile pwlib I get warnings like "../common/getdate.y: conflicts: 8 shift/reduce, 18 reduce/reduce" - is this normal?

4.28 - When I compile pwlib I get a warning like "In static member function `static std::ostream& PTrace::End(std::ostream&)': warning: unused variable 'rb'" - is this normal?

4.29 - How do I fix link errors about missing functions when compiling DLLs on Windows?

4.30 - How do I link OpenH323, PWLib or OPAL applications statically in Windows?

4.31 - How do I link OpenH323, PWLib or OPAL applications statically on Unix?

4.32 - How do I stop configure from finding the wrong header files on Windows?

4.33 - How do fix errors about missing "MSVC80.DLL" or "MSVCR80.DLL" file when debugging OPAL programs using Visual C++ 2005 Express Edition?

4.34 - How do I fix gcc errors about "PAtomicInteger" when compiling OpenH323 or OPAL?

4.35 - I cannot find the Console Components library files (ptclib.lib and ptclibd.lib) in recent builds of PWLib. Where are they?

5. CODECS

5.1 - Why is there no G.723.1/G.729 codec in OPAL or OpenH323?

5.2 - Can I use the ITU reference code for G.723.1 and G.729?

5.3 - Where can I get licensed G.723.1 and G.729 codec implementations?

5.4 - Can I use the Microsoft ACM G.723.1 codec in my Windows program?

5.5 - How do I use the H.263 video codec with NetMeeting?

5.6 - How do I add my own audio or video codec to Opal or OpenH323?

5.7 - What audio codecs are supported by OpenH323?

5.8 - What video codecs are supported by OpenH323?

5.9 - Where can I get more information on plugin codecs?

5.10 - Why does a call using a compressed audio codec use much more bandwidth than expected?

5.11 - What is the effect of changing the number of frames per packet for an audio codec?

5.12 - Why am I getting bad audio quality even though I am using G.711?

See 7.8

5.13 - Why am I getting bad audio when using the G.729 codec?

See 7.9

5.14 - How do I get the same codec in each direction when making a call?

5.15 - Why are there so many Speex capabilities?

5.16 - Does OpenH323 support wide-band codecs?

5.17 - Can I use the H.263 video codec in my program?

6. DOCUMENTATION

6.1 - Where can I get a design document for OpenH323?

6.2 - Where can I find the help file for OpenPhone?

6.3 - Where can I find user manuals for the Openh323 programs?

6.4 - Is there a programming tutorial on OpenH323?

6.5 - Is there documentation on audio codec plugins?

6.6 - Where can I get documentation on the API for PWLib and OpenH323?

6.7 - What documentation is available for OpenH323?

6.8 - Where can I find the specification documents for H.323?

6.9 - Is there a document on the configure.exe program used for configuring OpenH323 and PWLib on Windows?

7. USING OPENH323

7.1 - When I make a call I get audio in only one direction. What is the problem?

7.2 - I am behind a firewall and cannot receive incoming calls? Why not?

7.3 - I can establish a connection but no audio is transferred. What is wrong?

7.4 - How do I call NetMeeting with an OpenH323 client?

NetMeeting contains proprietary codecs such as G.723.1 that may be available on some OpenH323 clients. For example, MyPhone (see http://myphone.sourceforge.net) contains code that allows use of the MS-ACM G.723.1 codec on a Windows client. See 5.4 for more information

7.5 - I hear an echo when I speaking on a H.323 call - what is wrong?

7.6 - How can I test whether my client is working?

7.7 - I'm sure I have found a problem with OpenH323 - how do I report it?

See 4.10

7.8 - Why am I getting bad audio even though I am using the G.711 codec?

7.9 - Why am I getting bad audio when using the G.729 codec?

7.10 - When I start OpenGK/OpenMCU2/OpenIVR as a windows service process it won't start due to "error 1053" or similar. How do I fix this problem?

7.11 - How does OpenH323 support ENUM dialling?

7.12 - I am getting "Blocked" or other incorrect results when using STUN - how do I fix this?

7.13 - What are the different firewall types reported by STUN, and what do they mean?

7.14 - Why I am seeing messages like "RTP Packet from SSRC=xxxxxxxx ignored, expecting SSRC=yyyyyyyy" with audio only in one direction?

7.15 - How many simultaneous calls can OPAL/OpenH323 handle?

8. OPAL and OpenH323 applications

8.1 - What other projects use OpenH323?

8.2 What commercial and closed-source software uses Opal and OpenH323?

8.3 - What is the status of the OpenMCU program?

8.4 - How do I use OpenH323 with Asterisk?

9. Programming

9.1 How do I create a program that uses OpenH323 for call control, but uses an external RTP device?

9.2 - How do get a list of the codecs supported by OpenH323?

9.3 - When I enable PMEMORY_CHECK, I see all sorts of memory leaks reported. How do I fix these?

10. OPAL

10.1 - What is OPAL?

10.2 - Where can I download OPAL?

10.3 - How do I compile OPAL?

10.4 - How do I use SimpleOPAL to make a call?

10.5 - Is OpenH323 now obsolete or deprecated now that OPAL is released?

10.6 - Where can I find documentation on OPAL?

10.7 How do I use OPAL to make a call to a telephone number?

See the OpenH323 FAQ

TODO: copy sections to this Wiki