On Wed, Aug 20, 2008 at 1:43 PM, Maarten Sander
<info at privateer-software.nl>wrote:
> Hello,
>
> I'm developing a call-center application using PJSIP (actually, mostly
> PJSUA) and currently I'm trying to implement an inband-DTMF detector port
> (I can't rely on SIP INFO messages).
>
> Right now, I'm using SpanDSP for reading DTMF digits. However, it doesn't
> seem to work (no digits are received). Has anyone tried to integrate
> SpanDSP and PJSIP before?
>
>
Could you explain exactly what you mean by "doesn't work"?
> Currently, I'm feeding the samples as-is to SpanDSP, and I'm relying on
> SpanDSP's callback mechanism to receive the digits:
>
> static pj_status_t dtmfdet_put_frame(pjmedia_port *this_port,
> const pjmedia_frame *frame)
> {
> struct dtmfdet_port *dport = (struct dtmfdet_port*) this_port;
> dtmf_rx(&dport->state, (const pj_int16_t*) frame->buf,
> dport->base.info.samples_per_frame);
> return PJ_SUCCESS;
> }
>
>
Not knowing SpanDSP, that looks fine. But perhaps you'd want to handle the
case where frame->type is not FRAME_TYPE_AUDIO (i.e. just ignore them if
it's not audio).
static void dtmfdet_digits_rx(void *user_data, const char *digits,
> int len)
> {
> struct dtmfdet_port *dport = (struct dtmfdet_port*) user_data;
> int i;
>
> if (dport->cfg.cb.on_dtmf_digit != NULL) {
> for (i = 0; i < len; i++) {
> dport->cfg.cb.on_dtmf_digit(dport->cfg.call_id, digits[i]);
> }
> }
> }
>
> Is this the right way to do it? Should I convert the samples? I'm
> assuming the frame contains linear samples, and as far as I can tell,
> SpanDSP expects them to be linear.
>
>
The frame should contain linear samples.
Cheers
Benny
> Thanks for your help.
>
> Regards,
>
> Maarten
>
> P.S. I've also tried to implement the Goertzel algorithm
> (http://en.wikipedia.org/wiki/Goertzel_algorithm) directly, but it didn't
> work out, so I thought it would be wise to try integrating SpanDSP first.
> Eventually, I'd like to get rid of the SpanDSP dependency, and use Goertzel
> directly.
>
> --
> Privateer Software Development (www.privateer-software.nl)
> * web usability, web accessibility, web development
> * cross-platform software development
>
>
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