One-page reference: retransmission (RTX) vs FEC, the three FEC mechanisms from RFC 8854, Opus in-band FEC (LBRR) vs RED (RFC 2198) vs DRED, the bitrate costs and key numbers (1% LBRR threshold, 25% cap, ~58 kbps stereo minimum, 60%->18% concealment at distance 2), the SDP negotiation lines, and the rule for when to turn redundancy on.
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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
This cheat sheet compares RTX with FEC, Opus in-band FEC versus RED and DRED, their bitrate costs, the SDP lines and when to turn redundancy on. Volume 5 covers this in depth: FEC and RED, loss concealment, jitter buffers and NetEq, and bitrate and topology decisions for real-time audio. Written by Nikolay Sapunov, CEO at Fora Soft.
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