sipXtapi works on 10 ms audio frames. A core part of the library is a heartbeat message sent every 10 ms used to synchronize audio processing. Under Windows, this heartbeat message is generated each time the speaker device requests another buffer of audio (see function speakerCallbackProc() in file SpeakerThreadWnt.cpp in the sipXmediaLib project). If sipXtapi isnt able to open a speaker device, it sets up a Windows multimedia timer to generate a heartbeat every 10 ms. If the speaker thread is succeeding in using the Windows speaker device, then its quite likely that the heartbeat message is much less regular than when it is being generated from hardware.
Configuring sipXtapi to ignore the speaker device might improve things, as the Windows multimedia timer is probably more precise than the timing provided by the speaker driver, or compile with DISABLE_LOCAL_AUDIO. Stephen C. Steel From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Daniel Sigurgeirsson Sent: Friday, July 06, 2007 10:57 To: [email protected] Subject: Re: [sipxtapi-dev] Recording - again... Hi all, I just tested the same version (9770 with Jaroslavs recording patch) against my test setup (Axon PBX), and everything works fine. The only thing that is different between the two setups is that on the client site, the computer which was running my softphone application (I guess it is classified as a soft phone, even though it will only receive calls) is a server which didn't have any audio devices (except for some default Microsoft speaker device, which was muted and couldn't be unmuted). Does the recording function in sipxtapi require the computer to have functioning sound devices to be able to record sound? Regards, Daníel _____ From: [EMAIL PROTECTED] To: [email protected] Date: Thu, 5 Jul 2007 15:21:48 +0000 Subject: [sipxtapi-dev] Recording - again... Hi all, I'm deploying my application on the client computer, and recording doesn't work. A recording file is created, of the correct length, and it plays without errors in Windows Media Player, but absolutely nothing is recorded. I'm using a very recent version (rev. 9770 probably of sipxtapi), with Jaroslavs recording patch applied (by hand), and I modified the project settings so HAVE_SPEEX and HAVE_GSM are defined. I've done modifications so that both speaker and call are recorded, both contain the same, i.e. the same number of seconds of silence. When I connect to the same phone number using X-lite, I can hear sound/voice on both ends. Any ideas? What can I do to debug my way to figure out the problem? I cannot test the setup agains another phone station at the moment (but I will as soon as I can), so I cannot tell if the problem is in the code or if this has something do do with routing or other setup. I'm guessing that it would help running Wireshark/Ethereal, but my knowledge on how to configure it to watch RTP traffic is unfortunately lacking to say the least... Regards, Daníel _____ Play free games, earn tickets, get cool prizes! Join Live Search Club. Join <http://club.live.com/home.aspx?icid=CLUB_wlmailtextlink> Live Search Club! _____ Make every IM count. Download Windows Live Messenger and join the i'm Initiative now. It's free. Make <http://im.live.com/messenger/im/home/?source=TAGWL_June07> it count!
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