Changes between Initial Version and Version 1 of Ticket #2088
- Timestamp:
- Nov 8, 2019 10:11:37 AM (4 years ago)
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Ticket #2088
- Property Type changed from defect to enhancement
- Property Summary changed from Match telephone-event's clock rate in generating SDP answer to Generate and negotiate telephone-event with multiple clock-rates in SDP offer/answer
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Ticket #2088 – Description
initial v1 1 There seem to be an 'issue' in RFC4733 regarding telephone-event and multiple clock rates (see also [https://www.ietf.org/mail-archive/web/mmusic/current/msg12930.html here]), so some implementations put multiple telephone-events in its SDP when it offers codecs with various clock rates.1 Currently PJMEDIA will only generate and answer SDP with one telephone-event format, i.e: {{{telephone-event/8000}}}. But in the stream session, it will send DTMF using timestamp correctly according to the audio codec clock rate. 2 2 3 Unfortunately, for telephone-event format, currently PJMEDIA will only match the name, i.e: "telephone-event" and ignore the clock rate, so when answering SDP offer with multiple telephone-events, it will simply pick the first. 3 This ticket will update the PJMEDIA behavior in SDP offer/answer: 4 - in generatig SDP offer, it will generate one or more telephone-event formats, one for each clock rate, in accordance with the clock rates of the offered audio codecs. 5 - in generating SDP answer, it will select telephone-event clock rate based on the clock rate of the selected audio codec.