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This is the support site for Andrews & Arnold Ltd, a UK Internet provider. Information on these pages is generally for our customers but may be useful to others, enjoy!

SIP Audio Problems: Difference between revisions

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(→‎Advanced troubleshooting: it's not markdown ;))
* Get a pcap and use Wireshark to decode it
* Wireshark can play audio with different jitter buffer settings so you can sometimes recreate audio problems from the pcap
* Wireshark can [calculate jitter and delta stats](https://wiki.wireshark.org/RTP_statistics) calculate jitter and delta stats]
** Packets can arrive bunched up, with gaps between, or out of order. Jitter is a measurement of this.
** Wireshark calculates jitter as per the definition in [RFC3550](https://www.rfc-editor.org/rfc/rfc3550#page-94) RFC3550] so it uses a standard formula.
** Delta is the time difference between arrival of RTP packets. Max delta is the highest gap between arrival of packets. If the max delta is greater than the jitter buffer, audio will start getting dropped. Each packet usually contains 20ms of audio, so for high enough max delta you'll start to lose audio in 20ms chunks.
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