Live Streaming & Premieres
Packet loss
Also called: network loss
Every live stream is a run of packets travelling from your encoder to YouTube's ingest server, and packet loss is the share that go missing on the way. Unlike a slow file transfer there is no second chance to send them, because live video has to keep moving.
Viewers see stutter, smeared blocks or audio dropping out. Encoders show it as dropped frames. The usual causes are wifi instead of ethernet, a congested upload, or a bitrate set higher than the connection can sustain, and halving the bitrate fixes most of them.