RTP streams are easy peasy

A live coding session where the author builds a custom SIP/VoIP phone client in Zig to receive doorbell calls on a Linux computer. The session focuses on parsing RTP (Real-Time Protocol) packets received over UDP, decoding PCMU (G.711 mu-law) audio encoding, and visualizing the resulting sine wave. Key steps include opening a UDP socket in Zig, parsing the RTP header fields (version, sequence number, timestamp, SSRC), decoding PCMU audio samples using the mu-law formula from RFC 3551, and discovering that the encoded bits must be bit-inverted before decoding — a detail buried in the Wikipedia spec.