Transport-wide Congestion Control (transport-cc, TWCC) is the modern WebRTC scheme for estimating available bandwidth and adapting media rates to avoid congesting the network. Instead of the receiver computing the estimate (as in the older REMB), the receiver simply reports the arrival time of every packet back to the sender, and the sender runs the bandwidth-estimation algorithm itself. Centralizing the logic at the sender gives finer, faster, more consistent reaction to changing conditions and easier iteration. It governs how aggressively the encoders push bits; for audio the practical effect is graceful coexistence with video and adaptation as the link tightens, keeping latency low and avoiding the bufferbloat that wrecks real-time media.
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
Transport-CC decides how fast a WebRTC sender backs off when the network degrades, so it shapes both audio quality and call stability. Volume 5 covers bitrate and topology decisions in detail, with jitter buffers, FEC and RED and incident diagnosis by symptom, so you can tune Transport-CC behaviour for the networks your users actually have. Written by Nikolay Sapunov, CEO at Fora Soft.
WebRTC bitrate collapsing on weak networks, and Transport-CC feedback looks off?
Send us call stats and we will analyse your Transport-CC feedback and bandwidth estimates and return tuning settings for audio and video. 250+ video products shipped since 2005.
