Sometimes you need to play the audio of the SIP call within the Wireshark capture file. It's not that convenient to check audio wave detail, or control playback to listen more precisely in the Wireshark.
Therefore you need to output the audio and view it in a flexible audio software like Audition.
Here is a free web tool which helps you convert the RTP steams of the SIP call to wav file: Xplico
Disclaimer: if your call includes sensitive information, please avoid to upload the file to this web.
It's pretty easy to use this tool. Just upload your *.pcap file. (If you have *.pcapng file, just change the extension name as "pcap". )
Click Create Session > Add Files > Upload your file.
Within few seconds, the audio would be output. Click to download it.
After downloading, delete the WAV files, and the file you uploaded.