Packet loss concealment fills the hole left by a lost or too-late audio frame with a plausible synthetic reconstruction, so the listener hears a brief smooth stretch instead of a click, a gap, or silence. The simplest schemes repeat and fade the previous frame; codec-integrated PLC (as in Opus) extrapolates from the signal's recent pitch and spectrum for a far more natural patch; and the newest neural approaches, like Opus's deep PLC, actually generate missing speech. Concealment works well for isolated losses but degrades as loss grows and bursts, which is why it works hand in hand with FEC and the jitter buffer rather than alone.
The book · Volume 5 of 7
Audio for Video: A Complete Guide to Sound in Video Products: From Jitter Buffers and Lip Sync to Atmos, Quality Metrics, and Neural Codecs
Packet loss concealment decides whether a lost packet sounds like nothing at all or like a robotic stutter. This volume covers PLC in depth with jitter buffers, NetEq, FEC and RED, and symptom-based incident analysis, so you can choose the right mix of concealment and redundancy for your networks. Written by Nikolay Sapunov, CEO at Fora Soft.
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