Hi Dimitar, pjsip runs all media processing from the audio device callback, so it is important that the callbacks happen periodically at the frame rate, typically 10 or 20 msec. pjsip can tolerate some burstiness in the callbacks, say two reads followed by two writes, but long pauses will cause big problems. A typical implementation starts a high priority thread with a loop that polls the hardware device and makes the callbacks when data is to be transferred. Regards, Bill On 3/27/2015 2:38 PM, dpn at switchvoice.com wrote: > Hi Bill, > Thank you for the explanation. > The only conceptual think I am not clear for my pjsua application now is > if I can block in my audio device until my hardware has or requires > audio data. > Best Regards > Dimitar > *From:* Bill Gardner <mailto:billg at wavearts.com> > *Sent:* Friday, March 27, 2015 15:56 > *To:* pjsip at lists.pjsip.org <mailto:pjsip at lists.pjsip.org> > *Subject:* Re: [pjsip] TDM sound device to the pjmedia, how? > Hi Dimitar, > > You want to write a new audiodev following > pjmedia/include/pjmedia-audiodev/audiodev_imp.h, > then set up a macro to enable/disable this device, such as > PJMEDIA_AUDIO_DEV_HAS_TDM, > and then add the hooks in pjmedia\src\pjmedia-audiodev\audiodev.c so > pjmedia will use this device, > and then enable the device in config_site.h and disable the others. > > You can then enable/disable the hardware echo cancellation by using > the pjmedia capability > PJMEDIA_AUD_DEV_CAP_EC, then pjmedia can use the built-in AEC. > > Regards, > > Bill > > > > On 3/27/2015 8:30 AM, dpn at switchvoice.com wrote: >> Hi All, >> I?ve ported pjproject-1.16 on an embedded platform based on Mediatek >> MT 7620 CPU running OpenWRT. >> (Version 1.16 is rather old but I don?t need video and it seems it >> covers my needs. ) >> On this platform there is SLIC chip supporting FXS interface to an >> analog phone. >> The SLIC has TDM interface to the CPU and I have completed the TDM >> driver (running in the Linux kernel space) >> which works fine with Asterisk. >> Now I am trying to test pjsua (or some other basic pjsip user agent? >> ) so I would like to integrate my driver to pjmedia. >> I?ve checked the very clean pjsip documentation but still I am not >> fully clear how to approach the project. >> I think using PortAudio or ALSA will overcomplicate my experiment. >> My TDM driver expose ioctl interface which I can use from my pjsua >> application from the user space. >> I think the best would be to derive the application clock from my tdm >> driver. >> As far as I understand I should use ?Sound Device PortFramework? so >> eventually the application hooks >> two callbacks rec_cb and play_cb which are called when my TDM driver >> has frame of data or needs frame of data. >> I am looking at >> /pjproject-1.16/pjmedia/src/pjmedia-audiodev/null_dev.c which looks >> as the simplest starting point I could hack. >> However sound devices in pjmedia provide lot of stuff which I don?t >> think I need. >> For example acoustic echo cancelation. I don?t need that. >> I rather use line echo canceler in my TDM driver which is more >> important I think for my softphone example. >> From the other hand the ?Media Ports Framework? looks much cleaner >> than ?Sound Device PortFramework?. >> For example /pjproject-1.16/pjmedia/src/pjmedia/null_port.c looks >> much simpler than null_dev.c. >> But as far as understand using this framework the application calls >> the functions get_frame and put_frame so what I could do >> is to block the execution of those functions (using linux system call >> select() for example) >> and return when I get/send the frame data from/to my driver. This way >> I will get the timings provided from my driver to the pjsua. >> However I am not sure how this will fit with the SIP part of my test >> softphone. >> Anyone willing to clarify if I am on or fully out of track? Smile >> Thanks >> Dimitar >> >> >> _______________________________________________ >> Visit our blog:http://blog.pjsip.org >> >> pjsip mailing list >> pjsip at lists.pjsip.org >> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org > > ------------------------------------------------------------------------ > _______________________________________________ > Visit our blog: http://blog.pjsip.org > > pjsip mailing list > pjsip at lists.pjsip.org > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org > > > _______________________________________________ > Visit our blog: http://blog.pjsip.org > > pjsip mailing list > pjsip at lists.pjsip.org > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20150327/2145e665/attachment.html>
