At 10:37 AM 9/15/2009, Archie Rosenblum wrote:
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>Would someone mind pointing me in the right direction for capturing
>audio to a buffer? I have multiple inbound calls and I would like
>to check for in-band DTMF (no rfc2833). What is the API order for
>setting up PJSIP to get the audio data? I just need some framework
>help -- I have reviewed the sample files on the web site but I'm
>having trouble grasping which APIs to use. I do know how to do play
>audio files, it's the capturing to a buffer that has me confused. I
>mostly use the PJSUA APIs.
>
>Global
>---------
>pjsua_pool_create
>[Shared pool used for all calls]
>
>Call comes in (for each call do below)
>-------------
>pjmedia_mem_capture_create
>[What size buffer should I use? Does it matter?]
For FFT analysis I used a buffer size of 2000 bytes. The idea being
the bigger the buffer size the more accurate the result. The smaller
the buffer the more real time
the data result.
>[How do I get the call information such clockrate, etc, so I can set
>this API to use the same values as the call? Does it matter? Or
>should I use the values in the sample programs?]
Yes I think it matters. I use the pjsua_conf_get_port_info()
function to get this data then pass it along. It looks something like this:
pjsua_conf_get_port_info(sip_data[line].conf_slot, &info);
sip_data[line].cpa_clock_rate=info.clock_rate;
pjmedia_mem_capture_create(sip_data[line].cpa_pool,
sip_data[line].cpa_int_data, CPA_FFT_SIZE,
info.clock_rate, info.channel_count,
info.samples_per_frame, info.bits_per_sample, 0, &sip_data[line].cpa_port);
>
>pjmedia_mem_capture_set_eof_cb
>
>[How do I connect the call to this media port for so the media port
>is "listening" and the callback works]
// line_number is supplied by the application to sort out multiple
line implmentation.
pjmedia_mem_capture_set_eof_cb(sip_data[line].cpa_port,
&sip_data[line].line_number, cpa_fft_got_data);
// add the memory capture port to the bridge
pjsua_conf_add_port(sip_data[line].cpa_pool, sip_data[line].cpa_port,
&sip_data[line].cpa_conf_port);
// then connect the conf_slot for the call and the cpa_conf_slot.
pjsua_conf_connect(sip_data[line].conf_slot, sip_data[line].cpa_conf_port);
The callback function will look like this:
pj_status_t cpa_fft_got_data(pjmedia_port *port, void *usr_data)
{
usr_data will contain the line_number passed int.
Then I think you call pjmedia_port_get_frame(port, frame);
and frame->buf I think has your audio data.
Yea I didn't realize until I typed out this message, my code was
missing that piece. So
helping you helped me.
}
>
>
>Call ends
>----------
>pjmedia_port_destroy
>
>
>Thank you in advance,
>Archie
>
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