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.IX Title "Net::SIP::DTMF 3pm"
.TH Net::SIP::DTMF 3pm "2023-09-29" "perl v5.36.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Net::SIP::DTMF \- DTMF RTP packet generating and extracting
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 10
\&  use Net::SIP::DTMF;
\&  my $sub = dtmf_generator(
\&    11,                  # event \*(Aq#\*(Aq
\&        100,                 # duration 100ms
\&        rfc2833_type => 101, # RTP type 101 for telephone\-event/8000
\&        # audio_type => 0,   # RTP type 0 for PCMU/8000, 8 for PCMA/8000
\&  );
\&  while (...) {
\&        my @pkt = $sub\->($sequence,$timestamp,$srcid);
\&        last if ! @pkt;        # dtmf done
\&        next if $buf[0] eq \*(Aq\*(Aq; # more coming, but no data this time (pause)
\&        .. send @pkts ...
\&  }
\&
\&
\&  use Net::SIP::DTMF;
\&  my $sub = dtmf_extractor(
\&        rfc2833_type => 101, # RTP type 101 for telephone\-event/8000
\&        audio_type => 0,     # RTP type 0 for PCMU/8000, 8 for PCMA/8000
\&  );
\&  while (...) {
\&        if ( my ($event,$duration,$type) = $sub\->($packet)) {
\&          # event received
\&          ...
\&        }
\&  }
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This package provides functions for generating \s-1RTP\s0 packets containing \s-1DTMF\s0
events or extracting \s-1DTMF\s0 events from \s-1RTP\s0 packets.
.SH "FUNCTIONS"
.IX Header "FUNCTIONS"
.ie n .IP "dtmf_generator ( \s-1EVENT, DURATION,\s0 %ARGS )" 4
.el .IP "dtmf_generator ( \s-1EVENT, DURATION,\s0 \f(CW%ARGS\fR )" 4
.IX Item "dtmf_generator ( EVENT, DURATION, %ARGS )"
Generates a function which is used to generate packets for the given \s-1EVENT.\s0
.Sp
\&\s-1EVENT\s0 is the event numer (0..15) or undef if it should just generate silence or
pause. \s-1DURATION\s0 is the time for the event in ms. \s-1ARGS\s0 contain information how
the event should be packed: either as \s-1RFC2833 RTP\s0 event or as \s-1RTP\s0 audio
\&\s-1PCMU/8000\s0 or \s-1PCMA/8000.\s0
\&\f(CW%ARGS\fR can be
.RS 4
.IP "rfc2833_type => rtp_type" 8
.IX Item "rfc2833_type => rtp_type"
Gives the \s-1RTP\s0 payload type number for rfc2833 \s-1RTP\s0 events (telephone\-event/8000). 
If not given will try \fBaudio_type\fR instead.
.IP "audio_type => rtp_type" 8
.IX Item "audio_type => rtp_type"
Gives the \s-1RTP\s0 payload type number. 8 for \s-1PCMA/8000\s0 and 0 for \s-1PCMU/8000.\s0
If not given and no \fBrfc2833_type\fR given it will croak.
.IP "volume => volume" 8
.IX Item "volume => volume"
Sets the volume for \s-1RTP\s0 event according to rfc2833.
.RE
.RS 4
.Sp
The generated function should then be called with \s-1SEQUENCE,TIMESTAMP,SRCID\s0 to
generate the \s-1RTP\s0 packets and will return \f(CW@RTP_PACKETS\fR, with
.IP "() \- \s-1DTMF\s0 event is finished" 8
.IX Item "() - DTMF event is finished"
.PD 0
.ie n .IP "$RTP_PACKETS[0] eq '' \- no \s-1RTP\s0 packet for this call (pause)" 8
.el .IP "\f(CW$RTP_PACKETS\fR[0] eq '' \- no \s-1RTP\s0 packet for this call (pause)" 8
.IX Item "$RTP_PACKETS[0] eq '' - no RTP packet for this call (pause)"
.ie n .IP "@RTP_PACKETS \- \s-1RTP\s0 packets which can be send to the peer" 8
.el .IP "\f(CW@RTP_PACKETS\fR \- \s-1RTP\s0 packets which can be send to the peer" 8
.IX Item "@RTP_PACKETS - RTP packets which can be send to the peer"
.RE
.RS 4
.RE
.ie n .IP "dtmf_extractor ( %ARGS )" 4
.el .IP "dtmf_extractor ( \f(CW%ARGS\fR )" 4
.IX Item "dtmf_extractor ( %ARGS )"
.PD
Generates a function which is used to extract \s-1DTMF\s0 events.
Keys \fBrfc2833_type\fR and \fBaudio_type\fR have the same meaning as in
\&\fBgenerate_dtmf\fR. It will only attempt to extract \s-1DTMF\s0 events from rfc2833 \s-1RTP\s0
events or audio if the relevant rtp_type is given.
.Sp
The function will be called with the \s-1RTP\s0 packet as the only argument and will
return () if no new events where found or (\s-1EVENT,DURATION,TYPE\s0) if an event 
finished, where \s-1DURATION\s0 is the duration in ms and \s-1TYPE\s0 is audio|rfc2833.
.Sp
For performance reasons it is best to use only rfc2833 if the peer supports it.