Hi, The data in PJMedia is all in the time domain if you want to do in band DTMF detection , usually you use G?rtzels algoritm, which use recursive DFT on single frequencies. I don't have a reference but I'm sure if you browse internet or look in any DSP book you will find it. BR/Olle _____ From: pjsip-bounces@xxxxxxxxxxxxxxx [mailto:pjsip-bounces at lists.pjsip.org] On Behalf Of Benny Prijono Sent: den 27 januari 2009 09:23 To: pjsip list Subject: Re: PJSIP feature request..conference port audio frequency? On Tue, Jan 27, 2009 at 2:27 AM, David Clark <vdc1048 at tx.rr.com> wrote: Ok I see how to do most of it. As your posted suggestion for inband dtmf detection points out, looking at mp3_writer.c wav_writer.c I can see the audio is in a 16 bit array that is written out in either case. My question is the basic one. If you have port->buf[0] for example is that the frequency of the audio at that point. In short how do I relate audio sample data to frequency? FFT? Btw I thought you knew about this stuff and just looking for a place to hook it to. If you don't know about this then that makes it two of us. I also notice wav_writer.cpp and mp3_writer.c have put_frame functions that include a callback call if the function pointer if set. Is there any reason not to do this also in conference.c? Yea the put_frame in conference.c does not have such a feature. Not sure I understand this. The put_frame/get_frame callbacks are part of pjmedia_port framework and all media ports including the conference bridge have these. cheers Benny Thanks, David Clark -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20090127/d28b147d/attachment.html>
