To extract audio for every participant, we first grouped the RTP packets by SSRC. For every participant (SSRC), we created a SILK file, starting with the magic bytes “#!SILK_V3”. For every SSRC, we decrypted the bytes following the two-byte size worth (utilizing the similar AES-128 key in ECB mode). We wrote the decrypted bytes, prepended with the two-byte size worth (in little-endian byte order) from the RTP payload. We then obtained a SILK transcoder and efficiently transcoded every SILK file into an MP3 containing the audio from one of the members.

$ sh converter.sh uncooked.silk mp3