live-ingest §9.5: a WAI-aware WHEP player writes, per media section of its offer, the WAI
capabilities its sink dispatches, in its dispatch order, as SDP media capabilities
(RFC 6871) under capability negotiation (RFC 5939): a=csup:med-v0, then for each capability
§5.1 carries over WebRTC (wai.video.avc, vp8, vp9, av1, wai.audio.opus.packet) that the
section offers, an a=rmcap, an a=mfcap of its fmtp, and an a=pcfg whose number gives the
order. The egress gateway reads them back, refuses with 422 an offer whose capability
attributes do not parse or do not hold together (caps_malformed, caps_number_reused,
caps_config_reused, caps_unknown_capability, caps_payload_type, caps_option_missing,
caps_unsupported, caps_too_many; §9.5 and §14), forwards for each section the rendition the
first advertised capability names at or below the grant's max_layer, answered with a=acfg,
and the floor where nothing advertised is published. §17 records that joule-moq-ingest does
not read them yet.
wai::sdp_caps: read, Offer::advertised, pick and Pick::acfg, write. Its tests replay
live-conformance/sdp-caps/vectors.json (offers read and refused with every reason, picks,
offers written byte for byte and read back), write and read back every order of the video
capabilities, and hold §9.5's table and reasons and §14's to the module.
live-conformance/sdp_caps_verify.py, written from §9.5 and the RFCs' grammars and sharing no
code with wai-rs, recomputes every case and requires every mutated copy to fail.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
b19e078cc3