A datagram-aligned PyroWave session inflates the codec bitstream ×1.2–1.3
on its way to the wire — greedy packing of few-hundred-byte atomic block
packets into 1408 B windows zero-pads most window tails, plus the 4-byte
prefixes and FRAG chains. The 2026-07 field report's 1440p60 10-bit
"Automatic" pin of 407 Mb/s put a measured 550 Mb/s on a 1 GbE link;
nothing enforced the pin past the rate controller.
New shared WireBudget (pyrowave_wire.rs, both backends): tracks the real
per-frame AU/bitstream ratio as a ×1024 fixed-point EMA (prior ×1.25,
weight 1/8, clamped ×1.0–×2.0) and deflates the budget handed to
pyrowave's rate control by it, so the windowed AU lands on the configured
rate. Sealed-datagram framing (+4.5%) and FEC parity stay uncompensated —
H.26x sessions carry those on top of the configured bitrate too, and the
pin must mean the same thing for every codec.
Dense (non-chunked) sessions are untouched.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>