The four correctness seams from the 08-22 auto-bitrate review §2, chosen
options per the RFC (planning design/abr-stack-overhaul.md §3):
- §2.3: a failed bitrate-change encoder rebuild now snaps the client back
(retarget_tx) — the control task acks BEFORE the apply, so the client's
climb base, utilization and proven math tracked a rate the encoder
never ran until some later event happened to correct them.
- §2.2: the ABR rebuild announces PipelineGap on success, like the
mode-switch and topology rebuilds already do — a ~0.6 s host-local
stall read as congestion killed slow start for the session (the 401 ms
field case: minutes at ~15 Mbps on a clean link).
- §2.1: an accepted mode switch re-teaches the stream-shape cap —
computed once from the Welcome mode, 1080p→4K kept a 1080p-sized climb
ceiling and 4K→720p left an oversized one standing. A re-set
set_stream_cap also rebinds the already-learned ceiling downward
(set_ceiling deliberately never lowers); the FIRST set keeps the
founding semantics, pinned by the existing stream-bound test.
- §2.4: the bitrate_ack slot becomes a queue drained in arrival order —
latest-wins collapsed a full resolve ack + corrective short retarget
landing in the same 750 ms window, and host-cap learning needs two
CONSECUTIVE short acks.
punktfunk-core --features quic: 490 tests green natively, including the
new a_mode_switch_reteaches_the_stream_cap_both_ways.
enricobuehler