forked from unom/punktfunk
The ABR ceiling was the negotiated start rate, so an 'Automatic' session was permanently boxed at the 20 Mbps default no matter the link — the most user-visible cap left after the transport work lifted the client receive ceiling to ~4.8 Gbps wire. - Startup link-capacity probe: ~2 s into an Automatic session the pump fires one speed-test burst (2 Gbps target, 800 ms) over the existing ProbeRequest machinery; delivered wire throughput x0.7 (FEC + variance headroom) becomes the controller's climb ceiling via set_ceiling(). Old hosts decline (all-zero reply) or never answer (a 6 s timeout clears the stuck probe state so LossReports resume) — the ceiling then stays negotiated, exactly the old behavior. PUNKTFUNK_ABR_PROBE=0 opts out. - Slow start: until the first congestion signal, every cooled clean window DOUBLES the rate toward the ceiling (20 Mbps -> 640 Mbps in ~10 s) instead of +6% per ~10 s (which would have taken ~10 minutes). Any congestion signal ends it for good; classic AIMD takes over. - Faster, severity-aware AIMD: a SEVERE window (unrecoverable frame, jump-to-live flush, or >=6% loss) backs off x0.7 immediately instead of waiting two windows; ordinary congestion (2-6% loss, OWD rise) keeps the two-window fuse. Additive climbs need 6 clean windows (~4.5 s, was ~10 s); the change cooldown drops 3 s -> 1.5 s. - PUNKTFUNK_VBV_FRAMES now also scales the direct-NVENC VBV (Windows + Linux, previously hardwired to 1 frame) — parity with AMF/VAAPI/QSV. Each accepted step still costs an encoder rebuild + IDR on the host; in-place rate reconfigure (NvEncReconfigureEncoder / AMF dynamic properties / Vulkan per-frame RC) is the planned follow-up that makes stepping free. Controller tests rewritten to the new policy (severity classes, slow-start climb, ceiling semantics; 144 green). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>