- h323plus - lists.packetizer.com

OpenMCU and XMeeting
by Michael Miller 19 Sep '08

19 Sep '08

I'm having trouble with XMeeting and OpenMCU. XMeeting connects fine intially, but if another h.323 client joins the session, XMeeting disconnects and OpenMCU crashes. Here's what I get at the console for OpenMCU: *** glibc detected *** openmcu: free(): invalid pointer: 0x098912c8 *** ======= Backtrace: ========= /lib/libc.so.6[0xb49ac1] /lib/libc.so.6(cfree+0x90)[0xb4d0f0] /usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0x2fba6f1] /lib/libpt_linux_x86_r.so.2.0.1(_ZN13PAbstractList15DestroyContentsEv+0x19)[0xaa38a7] /lib/libpt_linux_x86_r.so.2.0.1(_ZN10PContainer8DestructEv+0x36)[0xaa8976] openmcu(_ZN13PAbstractListD2Ev+0x16)[0x8064856] /lib/libpt_linux_x86_r.so.2.0.1(_ZN7PSocket6SelectERS_S0_RK13PTimeInterval+0xa6)[0xa92caa] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN7RTP_UDP8ReadDataER13RTP_DataFramei+0x25)[0x67b621] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN16RTP_JitterBuffer6OnReadERPNS_5EntryERii+0x20)[0x70a632] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN16RTP_JitterBuffer16JitterThreadMainER7PThreadi+0x88)[0x70c57a] /lib/libpt_linux_x86_r.so.2.0.1(_ZN13PSimpleThread4MainEv+0x1d)[0xa9c287] /lib/libpt_linux_x86_r.so.2.0.1(_ZN7PThread14PX_ThreadStartEPv+0xea)[0xa8a678] /lib/libpthread.so.0[0x78050b] /lib/libc.so.6(clone+0x5e)[0xbb3b2e] ======= Memory map: ======== 00110000-00111000 r-xp 00110000 00:00 0 [vdso] 00111000-0077a000 r-xp 00000000 fd:00 49282 /lib/libh323_linux_x86_r.so.1.20-alpha2 0077a000-0077b000 rw-p 00669000 fd:00 49282 /lib/libh323_linux_x86_r.so.1.20-alpha2 0077b000-00790000 r-xp 00000000 fd:00 51534 /lib/libpthread-2.7.so 00790000-00791000 r--p 00014000 fd:00 51534 /lib/libpthread-2.7.so 00791000-00792000 rw-p 00015000 fd:00 51534 /lib/libpthread-2.7.so 00792000-00794000 rw-p 00792000 00:00 0 00794000-00797000 r-xp 00000000 fd:00 49532 /lib/libdl-2.7.so 00797000-00798000 r--p 00002000 fd:00 49532 /lib/libdl-2.7.so 00798000-00799000 rw-p 00003000 fd:00 49532 /lib/libdl-2.7.so 00799000-007c0000 r-xp 00000000 fd:00 51506 /lib/libm-2.7.so 007c0000-007c1000 r--p 00026000 fd:00 51506 /lib/libm-2.7.so 007c1000-007c2000 rw-p 00027000 fd:00 51506 /lib/libm-2.7.so 007c2000-007de000 r-xp 00000000 fd:00 445122 /usr/local/lib/ptlib/devices/videoinput/v4l2_pwplugin.so 007de000-007df000 rw-p 0001c000 fd:00 445122 /usr/local/lib/ptlib/devices/videoinput/v4l2_pwplugin.so 007df000-007fa000 r-xp 00000000 fd:00 445123 /usr/local/lib/ptlib/devices/videoinput/v4l_pwplugin.so 007fa000-007fb000 rw-p 0001b000 fd:00 445123 /usr/local/lib/ptlib/devices/videoinput/v4l_pwplugin.so 007fb000-00805000 r-xp 00000000 fd:00 49255 /lib/libnss_files-2.7.so 00805000-00806000 r--p 00009000 fd:00 49255 /lib/libnss_files-2.7.so 00806000-00807000 rw-p 0000a000 fd:00 49255 /lib/libnss_files-2.7.so 008b6000-008d1000 r-xp 00000000 fd:00 49338 /lib/ld-2.7.so 008d1000-008d2000 r--p 0001a000 fd:00 49338 /lib/ld-2.7.so 008d2000-008d3000 rw-p 0001b000 fd:00 49338 /lib/ld-2.7.so 008d3000-00adb000 r-xp 00000000 fd:00 49337 /lib/libpt_linux_x86_r.so.2.0.1 00adb000-00add000 rw-p 00208000 fd:00 49337 /lib/libpt_linux_x86_r.so.2.0.1 00add000-00ae0000 rw-p 00add000 00:00 0 00ae0000-00c33000 r-xp 00000000 fd:00 49340 /lib/libc-2.7.so 00c33000-00c35000 r--p 00153000 fd:00 49340 /lib/libc-2.7.so 00c35000-00c36000 rw-p 00155000 fd:00 49340 /lib/libc-2.7.so 00c36000-00c39000 rw-p 00c36000 00:00 0 026c9000-026d9000 r-xp 00000000 fd:00 51559 /lib/libresolv-2.7.so 026d9000-026da000 r--p 00010000 fd:00 51559 /lib/libresolv-2.7.so 026da000-026db000 rw-p 00011000 fd:00 51559 /lib/libresolv-2.7.so 026db000-026dd000 rw-p 026db000 00:00 0 02e90000-02e9b000 r-xp 00000000 fd:00 51527 /lib/libgcc_s-4.1.2-20070925.so.1 02e9b000-02e9c000 rw-p 0000a000 fd:00 51527 /lib/libgcc_s-4.1.2-20070925.so.1 02f07000-02fe7000 r-xp 00000000 fd:00 5619850 /usr/lib/libstdc++.so.6.0.8 02fe7000-02feb000 r--p 000df000 fd:00 5619850 /usr/lib/libstdc++.so.6.0.8 02feb000-02fec000 rw-p 000e3000 fd:00 5619850 /usr/lib/libstdc++.so.6.0.8 02fec000-02ff2000 rw-p 02fec000 00:00 0 08048000-0807d000 r-xp 00000000 fd:00 88310 /usr/local/bin/openmcu 0807d000-08088000 rw-p 00034000 fd:00 88310 /usr/local/bin/openmcu 08088000-08089000 rw-p 08088000 00:00 0 Aborted ###################################################### *** glibc detected *** openmcu: malloc(): memory corruption (fast): 0x08afa618 *** ======= Backtrace: ========= /lib/libc.so.6[0xb4a8ac] /lib/libc.so.6(__libc_malloc+0x7b)[0xb4bb7b] /usr/lib/libstdc++.so.6(_Znwj+0x27)[0x2fbbba7] /lib/libpt_linux_x86_r.so.2.0.1(_ZN10PContainerC2Ei+0x17)[0xaa6945] /lib/libpt_linux_x86_r.so.2.0.1(_ZN14PAbstractArrayC2Eii+0x13)[0xaa8fad] /lib/libpt_linux_x86_r.so.2.0.1(_ZN10PBaseArrayIcEC2Ei+0x15)[0xa22119] /lib/libpt_linux_x86_r.so.2.0.1(_ZN10PCharArrayC2Ei+0x13)[0xaae873] /lib/libpt_linux_x86_r.so.2.0.1(_ZN7PStringC1Ev+0x12)[0xaaabbc] /lib/libpt_linux_x86_r.so.2.0.1(_ZN12PDTMFDecoder6DecodeEPKsi+0x11)[0xa3dff3] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN14H323Connection21OnUserInputInBandDTMFERN9H323Codec10FilterInfoEi+0x27)[0x639441] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN9H323Codec8WriteRawEPvi+0x92)[0x66b80a] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN20H323FramedAudioCodec5WriteEPKhjRK13RTP_DataFrameRj+0x12f)[0x66b9f7] /lib/libh323_linux_x86_r.so.1.20-alpha2(_ZN15H323_RTPChannel7ReceiveEv+0x2c3)[0x670ff9] /lib/libpt_linux_x86_r.so.2.0.1(_ZN7PThread14PX_ThreadStartEPv+0xea)[0xa8a678] /lib/libpthread.so.0[0x78050b] /lib/libc.so.6(clone+0x5e)[0xbb3b2e] ======= Memory map: ======== 00110000-00111000 r-xp 00110000 00:00 0 [vdso] 00111000-0077a000 r-xp 00000000 fd:00 49282 /lib/libh323_linux_x86_r.so.1.20-alpha2 0077a000-0077b000 rw-p 00669000 fd:00 49282 /lib/libh323_linux_x86_r.so.1.20-alpha2 0077b000-00790000 r-xp 00000000 fd:00 51534 /lib/libpthread-2.7.so 00790000-00791000 r--p 00014000 fd:00 51534 /lib/libpthread-2.7.so 00791000-00792000 rw-p 00015000 fd:00 51534 /lib/libpthread-2.7.so 00792000-00794000 rw-p 00792000 00:00 0 00794000-00797000 r-xp 00000000 fd:00 49532 /lib/libdl-2.7.so 00797000-00798000 r--p 00002000 fd:00 49532 /lib/libdl-2.7.so 00798000-00799000 rw-p 00003000 fd:00 49532 /lib/libdl-2.7.so 00799000-007c0000 r-xp 00000000 fd:00 51506 /lib/libm-2.7.so 007c0000-007c1000 r--p 00026000 fd:00 51506 /lib/libm-2.7.so 007c1000-007c2000 rw-p 00027000 fd:00 51506 /lib/libm-2.7.so 007c2000-007de000 r-xp 00000000 fd:00 445122 /usr/local/lib/ptlib/devices/videoinput/v4l2_pwplugin.so 007de000-007df000 rw-p 0001c000 fd:00 445122 /usr/local/lib/ptlib/devices/videoinput/v4l2_pwplugin.so 007df000-007fa000 r-xp 00000000 fd:00 445123 /usr/local/lib/ptlib/devices/videoinput/v4l_pwplugin.so 007fa000-007fb000 rw-p 0001b000 fd:00 445123 /usr/local/lib/ptlib/devices/videoinput/v4l_pwplugin.so 007fb000-00805000 r-xp 00000000 fd:00 49255 /lib/libnss_files-2.7.so 00805000-00806000 r--p 00009000 fd:00 49255 /lib/libnss_files-2.7.so 00806000-00807000 rw-p 0000a000 fd:00 49255 /lib/libnss_files-2.7.so 008b6000-008d1000 r-xp 00000000 fd:00 49338 /lib/ld-2.7.so 008d1000-008d2000 r--p 0001a000 fd:00 49338 /lib/ld-2.7.so 008d2000-008d3000 rw-p 0001b000 fd:00 49338 /lib/ld-2.7.so 008d3000-00adb000 r-xp 00000000 fd:00 49337 /lib/libpt_linux_x86_r.so.2.0.1 00adb000-00add000 rw-p 00208000 fd:00 49337 /lib/libpt_linux_x86_r.so.2.0.1 00add000-00ae0000 rw-p 00add000 00:00 0 00ae0000-00c33000 r-xp 00000000 fd:00 49340 /lib/libc-2.7.so 00c33000-00c35000 r--p 00153000 fd:00 49340 /lib/libc-2.7.so 00c35000-00c36000 rw-p 00155000 fd:00 49340 /lib/libc-2.7.so 00c36000-00c39000 rw-p 00c36000 00:00 0 026c9000-026d9000 r-xp 00000000 fd:00 51559 /lib/libresolv-2.7.so 026d9000-026da000 r--p 00010000 fd:00 51559 /lib/libresolv-2.7.so 026da000-026db000 rw-p 00011000 fd:00 51559 /lib/libresolv-2.7.so 026db000-026dd000 rw-p 026db000 00:00 0 02e90000-02e9b000 r-xp 00000000 fd:00 51527 /lib/libgcc_s-4.1.2-20070925.so.1 02e9b000-02e9c000 rw-p 0000a000 fd:00 51527 /lib/libgcc_s-4.1.2-20070925.so.1 02f07000-02fe7000 r-xp 00000000 fd:00 5619850 /usr/lib/libstdc++.so.6.0.8 02fe7000-02feb000 r--p 000df000 fd:00 5619850 /usr/lib/libstdc++.so.6.0.8 02feb000-02fec000 rw-p 000e3000 fd:00 5619850 /usr/lib/libstdc++.so.6.0.8 02fec000-02ff2000 rw-p 02fec000 00:00 0 08048000-0807d000 r-xp 00000000 fd:00 88310 /usr/local/bin/openmcu 0807d000-08088000 rw-p 00034000 fd:00 88310 /usr/local/bin/openmcu 08088000-08089000 rw-p 08088000 00:00 0 08a6d000-08b85000 rw-p 08a6d000 00:00 0 [heap] b7800000-b7821000 rw-p b7800000 00:00 0 b7821000-b7900000 ---p b7821000 00:00 0 b796a000-b796b000 ---p b796a000 00:00 0 b796b000-b79ab000 rw-p b796b000 00:00 0 b79ab000-b79ac000 ---p b79ab000 00:00 0 b79ac000-b79ec000 rw-p b79ac000 00:00 0 b79ec000-b79ed000 ---p b79ec000 00:00 0 b79ed000-b7a2d000 rw-p b79ed000 00:00 0 b7a2d000-b7a2e000 ---p b7a2d000 00:00 0 b7a2e000-b7a6e000 rw-p b7a2e000 00:00 0 b7a6e000-b7a6f000 ---p b7a6e000 00:00 0 b7a6f000-b7aaf000 rw-p b7a6f000 00:00 0 b7aaf000-b7ab0000 ---p b7aaf000 00:00 0 b7ab0000-b7b16000 rw-p b7ab0000 00:00 0 b7b16000-b7b17000 ---p b7b16000 00:00 0 b7b17000-b7b57000 rw-p b7b17000 00:00 0 b7b57000-b7b58000 ---p b7b57000 00:00 0 b7b58000-b7b98000 rw-p b7b58000 00:00 0 b7b98000-b7b99000 ---p b7b98000 00:00 0 b7b99000-b7bd9000 rw-p b7b99000 00:00 0 b7bd9000-b7bda000 ---p b7bd9000 00:00 0 b7bda000-b7c1a000 rw-p b7bda000 00:00 0 b7c1a000-b7c1b000 ---p b7c1a000 00:00 0 b7c1b000-b7ca7000 rw-p b7c1b000 00:00 0 b7ca7000-b7ca8000 ---p b7ca7000 00:00 0 b7ca8000-b7ce8000 rw-p b7ca8000 00:00 0 b7ce8000-b7ce9000 ---p b7ce8000 00:00 0 b7ce9000-b7d29000 rw-p b7ce9000 00:00 0 b7d29000-b7d2a000 ---p b7d29000 00:00 0 b7d2a000-b7d6a000 rw-p b7d2a000 00:00 0 b7d6a000-b7d6b000 ---p b7d6a000 00:00 0 b7d6b000-b7dab000 rw-p b7d6b000 00:00 0 b7dab000-b7dac000 ---p b7dab000 00:00 0 b7dac000-b7dec000 rw-p b7dac000 00:00 0 b7dec000-b7ded000 ---p b7dec000 00:00 0 b7ded000-b7e2d000 rw-p b7ded000 00:00 0 b7e2d000-b7e2e000 ---p b7e2d000 00:00 0 b7e2e000-b7e6e000 rw-p b7e2e000 00:00 0 b7e6e000-b7e6f000 ---p b7e6e000 00:00 0 b7e6f000-b7eaf000 rw-p b7e6f000 00:00 0 b7eaf000-b7eb0000 ---p b7eaf000 00:00 0 b7eb0000-b7ef4000 rw-p b7eb0000 00:00 0 b7f00000-b7f01000 rw-p b7f00000 00:00 0 bfbec000-bfc01000 rw-p bffeb000 00:00 0 [stack] Aborted The system is Fedora8. Please let me know if more info is needed. myk "If you're clear in your vision and trust the people in your team with clear objectives, they will invariably do their best to achieve everything desired, and usually deliver everything you could have hoped for and even more." -Paul Debevec

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Re: [h323plus] H323 error codes
by mayank＠in.niksun.com 19 Sep '08

19 Sep '08

Thanks a lot Robert for your prompt response. I got confused with your answer. Actually I posted 2 questions so the answer if of which question. The 2 questions are Actually I am looking for error codes in H323 protocols. 1) In H225/Q931 what could be the error codes. Is these error codes comes along with the last message "Release complete message" ? are in between the call.I am able to find these kind of codes specifically in SIP with the response messages with their numbers(Ex:400,500,..),similarly the case with the MGCP protocol.But,I am very much confused with the H.323. 2)What could be the case with the H.245 protocol. On Friday 19 Sep 2008 12:24:00 pm Robert Jongbloed wrote: > Pretty sure it doesn't. > > > Robert Jongbloed > OPAL/OpenH323/PTLib Architect and Co-founder. > > > -----Original Message----- > > From: h323plus-bounces(a)lists.packetizer.com [mailto:h323plus- > > bounces(a)lists.packetizer.com] On Behalf Of mayank(a)in.niksun.com > > Sent: Friday, 19 September 2008 4:32 PM > > To: h323plus(a)lists.packetizer.com > > Subject: [h323plus] H323 error codes > > > > Hi all, > > > > In Q931 protocol is it necessary that the cause code will come in > > last > > message. Does H245 contains the cause codes. > > Thanks > > Mayank Jain -- ---------------------------------------------------------------------------- Regards Mayank Jain Nawal mayank(a)in.niksun.com http://www.niksun.com Tel: +91 9818390836 +91 124-2316012(109)

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H323 error codes
by mayank＠in.niksun.com 19 Sep '08

19 Sep '08

Hi all, In Q931 protocol is it necessary that the cause code will come in last message. Does H245 contains the cause codes. Thanks Mayank Jain

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(no subject)
by mayank＠in.niksun.com 19 Sep '08

19 Sep '08

-- ---------------------------------------------------------------------------- Regards Mayank Jain Nawal mayank(a)in.niksun.com http://www.niksun.com Tel: +91 9818390836 +91 124-2316012(109)

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Cosmetic issues PTLib v2.0.1 with VS2008-SP1
by Marcos Fábio Jardini 09 Sep '08

09 Sep '08

Hello Reporting some cosmetic issues during compiling PTLib on VS2008-SP1. The files: vsdl.cxx pvfiledev.cxx pstun.cxx Have the macro '#define P_FORCE_STATIC_PLUGIN', the VS compiler outputs: 1>..\..\ptclib\{one of above} : warning C4603: 'P_FORCE_STATIC_PLUGIN' : macro is not defined or definition is different after precompiled header use 1> Add macro to precompiled header instead of defining here 1> ..\..\ptclib\{one of above} : use of precompiled header But the <ptlib/pluginmgr.h> includes <ptlib/plugin.h>, the later already define 'P_FORCE_STATIC_PLUGIN' when compiling under _WIN32. So remove or comment the #define P_FORCE_STATIC_PLUGIN from: vsdl.cxx pvfiledev.cxx pstun.cxx //============================ sockets.cxx The '#include <ptlib.h>' is the pre-compiled header and MUST come 1st so, changing '#include <ptlib.h>' to come before '#ifdef __NUCLEUS_PLUS__' >>>before: #ifdef __NUCLEUS_PLUS__ #include <ConfigurationClass.h> #endif #include <ptlib.h> >>>after: #include <ptlib.h> #ifdef __NUCLEUS_PLUS__ #include <ConfigurationClass.h> #endif //============================ Error: sphelper.h(1170) GetUserDefaultUILanguage(): identifier not found Configure is using c:\program files\microsoft sdks\windows\v6.0a\ for Located Speech API compile without speech support. -- ----- Jogue RPG, alimente o lado criativo!

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Registering with the GnuGK - continued
by Amnon David 03 Sep '08

03 Sep '08

Hard coding the authenticator.Enable (as shown bellow) solves the registration problem. Obviously this is not good - any ideas why authenticator.IsCapability returns the wrong result in the "simple" sample application ? BOOL H323Gatekeeper::OnReceiveGatekeeperConfirm(const H225_GatekeeperConfirm & gcf) { if (!H225_RAS::OnReceiveGatekeeperConfirm(gcf)) return FALSE; PINDEX i; for (i = 0; i < authenticators.GetSize(); i++) { H235Authenticator & authenticator = authenticators[i]; if (authenticator.UseGkAndEpIdentifiers()) authenticator.SetRemoteId(gatekeeperIdentifier); } if (gcf.HasOptionalField(H225_GatekeeperConfirm::e_authenticationMode) && gcf.HasOptionalField(H225_GatekeeperConfirm::e_algorithmOID)) { for (i = 0; i < authenticators.GetSize(); i++) { H235Authenticator & authenticator = authenticators[i]; authenticator.Enable( TRUE /*authenticator.IsCapability(gcf.m_authenticationMode, // <<<< This makes it work gcf.m_algorithmOID)*/); PTRACE(4,"RAS\tAuthenticator " << authenticator.GetName() << (authenticator.IsActive() ? " ACTIVATED" : " disabled")); } }

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Re: [h323plus] Multicast
by Troy 28 Aug '08

28 Aug '08

Thanks for your input Marcos. I have already looked at OpenMCU but it seems to be too different from what is required for a decentralised conference. As I recall, the signalling involved in OpenMCU is the default behaviour of the base classes for the most part. It wasn't clear to me how to change the signalling to identify distributed multicast but I'm still researching this. But the biggest question I have is how difficult it will be to add multicast capability to the library. Is it as simple as joining a multicast group if the network address is a multicast address and having everything else basically just work (same code to send/receive on an established multicast socket as for a UDP unicast socket) or is there more to it than that... maybe some additional management associated with H.323/H.245/H225.0/???? under this circumstance? So nobody else can provide any pointers/opinions? Troy. On Wed, 2008-08-20 at 09:26 -0300, Marcos Fábio Jardini wrote: > Hi Troy > > Try see "http://www.packetizer.com/ipmc/h323/whatsnew_v4.html - > Multiplexed Stream Transmission" for some hint > > In your case each endpoint must act as a MCU, what is need is to > investigate the recomendations and see if more than one of end-point > can signal herselfs as MCU capanility > > See the OpenMCU implementation as the begining point of how implement > the mcu capable signaling. > > Another good point is our CVS > (http://sourceforge.net/cvs/?group_id=194599) there you can see other > reference implementations, like NAT/Firewall Traversal etc. > > PS.: is not necessary to create a 'trash' account for this group, is > not a group with many messages and we have no problems with spam > > 2008/8/18 Junk-Mail Wastebasket <blindDrop(a)shaw.ca> > Greetings H323Plus devs. > > I have need of an ability to support a conference where each > end-point can/will manipulate the audio stream coming from > every other end-point based on some data associated with each > end-point. To me, it seems like each end-point should > multicast the audio stream and possibly the data that each > other end-point will use to modify the audio stream. Each > end-point should listen for multicasts associated with the > conference and modify and mix the streams as required based on > the data. From my internet searches, this seems to be more or > less the classic decentralised/distributed multipoint > conference. > > I have attempted to search the mailing list archives and code > for how to do this with H323 Plus and have found that the > capability appears to be lacking. Although I am willing to > work on developing this capability, I am far from expert on > H323 (Plus or otherwise) or VoIP and would need some strong > pointers from those of you who are expert. I would appreciate > some input on how best to proceed to get the functionality for > which I'm looking. > > Your suggestions would be most welcome, > > Troy. > > > > -- > ----- > Jogue RPG, alimente o lado criativo! >

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How to enable P_DIRECTSHOW in ptlib
by JobsGuo 27 Aug '08

27 Aug '08

hi: Anyone know how to enable P_DIRECTSHOW? Although I have install Directshow SDK and set the directory in vs2003, when I complie the ptlib,the P_DIRECTSHOW is still undef in ptbuildopts.h.then it cannot support DirectShow. who can help me to make the P_DIRECTSHOW is defined? thanks! 2008-08-27 JobsGuo

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silly question but...
by Amnon David 24 Aug '08

24 Aug '08

Has anyone ever managed to register with the GNU Gatekeeper using the "simple" sample application ? Whichever method I try, I get a SecurityDenial from the Gatekeeper Will appreciate any help on this -Amnon

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Multicast
by Junk-Mail Wastebasket 20 Aug '08

20 Aug '08

Greetings H323Plus devs. I have need of an ability to support a conference where each end-point can/will manipulate the audio stream coming from every other end-point based on some data associated with each end-point. To me, it seems like each end-point should multicast the audio stream and possibly the data that each other end-point will use to modify the audio stream. Each end-point should listen for multicasts associated with the conference and modify and mix the streams as required based on the data. From my internet searches, this seems to be more or less the classic decentralised/distributed multipoint conference. I have attempted to search the mailing list archives and code for how to do this with H323 Plus and have found that the capability appears to be lacking. Although I am willing to work on developing this capability, I am far from expert on H323 (Plus or otherwise) or VoIP and would need some strong pointers from those of you who are expert. I would appreciate some input on how best to proceed to get the functionality for which I'm looking. Your suggestions would be most welcome, Troy.

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