H323plus does not call to_customise_options function. This is only for Opal. Simon From: h323plus-bounces@lists.packetizer.com [mailto:h323plus-bounces@lists.packetizer.com] On Behalf Of Vladimir Fekete Sent: 25 February 2011 23:33 To: opalvoip-devel@lists.sourceforge.net Cc: h323plus@lists.packetizer.com Subject: [h323plus] "possible" bug in H323plus video codec for h.264 Hello all, I've been playing with h.264-x264 plugin for a while and since I had no problems between h323plus vs h323plus nor OpenPhone 3.8.3 application I do have problems with video codec h.264 for h323 from recent h323 plus (e.g. version 1.22.0, 01/11/2011) and application based on recent opal (rev. 25192) I say "possible" because - as was said from few recent mails on mailing lists, opal and h323+ have similar root but they don't share plugins (necessarily). Nevertheless, when I tried to make a connection from OPAL application to h323+ based application, where both used h264-x264 plugin from h323plus video codecs (v. 1.22.0), my opal application crashed. I traced down the problem and fixed the lines in h264-x264.cxx and now it works for me. Problem was following : during the codec options set stage a method of OpalPluginMediaFormatInternal class is called. This one (opalpluginmgr.cxx) bool OpalPluginMediaFormatInternal::AdjustOptions(OpalMediaFormatInternal & fmt, OpalPluginControl & control) const call was made from void H323Capabilities::BuildPDU(const H323Connection & connection, H245_TerminalCapabilitySet & pdu) const line n.2706 (capability.GetWritableMediaFormat().ToCustomisedOptions();) in h323caps.cxx in method AdjustOptions there are 2 variables set inside : char ** input = fmt.GetOptions().ToCharArray(false); char ** output = input; and yes there are set *correctly* they are immediately followed by this line (in my case line n. 477 in opalpluginmgr.cxx) bool ok = control.Call(&output, sizeof(output)) != 0; which calls (opalpluginmgr.h) int OpalPluginControl::Call(void * parm, unsigned parmLen, void * context = NULL) const and that one calls int OpalPluginControl::Call(void * parm, unsigned * parmLen, void * context = NULL) const (these 2 methods are not same, difference is in the second parameter, one is not a pointer other is) and this second Call(..) calls to_customised_options from h264_x264.cxx static int to_customised_options(const struct PluginCodec_Definition * codec, void * _context, const char *, void * parm, unsigned * parmLen) and there is a line (in my case 837) const char ** option = (const char **)parm; and here is the problem. if you look at the chain : AdjustOptions > Call > the "other" Call > to_customised_options then you see that the output variable is transfered as : AdjustOptions &output char*** Call parm void * Call parm void * to_customised_options parm void* so in the end, parm is char *** and not char ** and this caused the crash How I fixed it changed "to_custoimized_options", file h323plus/plugins/video/H.264/h264-x264.cxx, line number 837 const char ** option = (const char **)parm; to const char ** option = *((const char ***)parm); and also (same function, same file, line 858) char ** options = (char **)parm; to char ** options = *((char ***)parm); recompiled h264 plugin and it works. Best regards, Vladimir Fekete P.S. I don't want to call it a bug because I'm not sure whether it's valid to mix h323plus codecs with opal (eg. separately they may work ok).