The ST 2110-20 receive path in joule-moq-ingest no longer makes a system call and an allocation and a wake-up a datagram on the gateway's runtime (D66's finding at 1920 x 1080 and 60, about 218 000 datagrams a second). st2110::rx reads each stream's socket on a thread that does nothing else, into the session's one bounded queue: on Linux one recvmmsg up to 64 buffers with UDP_GRO (a run of datagrams of one size cut back at the size the kernel states), the kernel's arrival stamps (SO_TIMESTAMPNS) and its count of buffers a full receive buffer dropped (SO_RXQ_OVFL); elsewhere one recvmsg a datagram with SO_TIMESTAMP, and on macOS the thread asks for QOS_CLASS_USER_INTERACTIVE. The system calls are in st2110::sock on libc's structures, each with its SAFETY note. The readers are untouched: the reorder, loss and completeness rules, the corpus (--check) and every earlier test pass as they were. st2110::timing reads a video stream's arrivals against the Network Compatibility Model of the sender type its description names (ST 2110-21:2022 §6.6.1, C_MAX of §7.1), counting a frame outside only where C_INST passed C_MAX by more than one, since the drain grid's phase is the gateway's; it is a reading, never the sender's compliance (sender_type_checked stays "no"), and the Virtual Receiver Buffer Model is not read. st2110::pace is the test sender on ST 2110-21's linear schedule, four packets at an instant and never sooner than the model drains them, by sendmmsg with UDP_SEGMENT on Linux. tests/essence_rx.rs holds the way in to broadcast rates on request; tests/essence_rt.rs sends with the pacer and takes WAI_RT_MAXUDP (ST 2110-10's Extended UDP Size Limit, stated as MAXUDP). Planted faults, each caught: a batch that drops its last datagram; coalesced datagrams cut a size off either way; a sender bursting whole frames against a description of a narrow sender (through a session, and over computed arrivals). WAI essence-contribution §10.10 (new), §3, §10.1, §10.7, §10.9, §12. Co-Authored-By: Claude Opus 5.5 <[email protected]>
38 KiB
joule-moq-ingest
A gateway between contribution protocols and the MoQ tracks of a WAI room. A standard
WebRTC encoder publishes into a room over WHIP (RFC 9725), and an RTMP encoder over
Enhanced RTMP v2 (v2-2026-01-31-r2), single-track or multitrack, over TCP or TLS; the
gateway becomes their tracks' MoQ publisher at the relay and signs every group's receipts as
the first hop. A standard WebRTC player watches a room's tracks over WHEP
(draft-ietf-wish-whep-05); the gateway subscribes at the relay and verifies every object's
receipt before it hands the frame on. A broadcast automation system drives the gateway's
SCTE 104 injector, which translates its requests to SCTE 35 and signs them as the room's
cues. It also takes contribution over SRT and RIST into the same tracks
(extensions/live-contribution.md, below), and signs each such link's record of loss,
recovery and latency. The mappings it implements are WAI's extensions/live-ingest.md,
extensions/cue-injection.md and extensions/live-contribution.md.
It is a library (GatewayServer, Gateway) and a binary, wai-ingest (the crate keeps its
name). The relay is joule-moq-relay (binary wai-relay); the MOQT codec is joule-moq's. The gateway's sessions with the relay speak the draft [relay] draft names, offered alone in the ALPN: 22 by default, or 23, 18 or 16, bridged to the gateway's -22 model by joule-moq-relay's transport::bridge.
GatewayServer::shutdown stops listening, ends every session (each signs its record, ended
deleted; an RTMP publisher as below), and returns once every task the gateway ran has ended:
every port it listened on is closed by then (HTTP, RTMP, RTMPS, SRT, the injector's, and each
RIST session's, waiting or running), and every connection it accepted. A gateway can start again
on the same ports at once, in the same process. A session that starts once the shutdown has
begun ends at once, gateway_stopped; Gateway::spawn runs a task the shutdown waits for.
So does one still dialing the relay when the shutdown begins (a dial can last 10 s, past the
5 s the shutdown waits for its tasks): it signs its record, gateway_stopped, with nothing
published. A task still running 5 s on is ended; a RIST listener it held is closed all the same
(Gateway::hold_rist: whatever binds one for a task of the gateway's hands it there as it
binds it; contrib::serve_rist serves a RIST session at its listener so).
GatewayServer::start binds every port and makes every check (the RTMPS identity, the
injector's key and grant) before it spawns a task to serve one. A start refused part way
returns its error with every port it bound free and nothing of its running, so the next start
can bind them at once.
Resources
| resource | methods |
|---|---|
/whip |
POST an application/sdp offer: 201, the answer, Location, ETag. OPTIONS (CORS, Accept-Post), GET, HEAD |
/whip/s/<id> |
PATCH an application/trickle-ice-sdpfrag: trickle ICE (204) or an ICE restart (200, a fragment, a new ETag); DELETE (200) ends the session and its tracks |
/whep/<room>/<owner>[?layer=<n>] |
POST an offer for the owner's tracks: 201, or 409 with Retry-After while the owner is not live. HEAD answers with Link: <urn:ietf:params:whep>; rel="profile" (WHEP §4.2) |
/whep/s/<id> |
PATCH, DELETE, as for WHIP |
/rtmp |
POST: 201, {"expires_in", "stream_key", "url"}: a one-time stream key for an Enhanced RTMP publish under the grant |
/metrics |
GET, HEAD: the gateway's counters in the text exposition format (wai/wai-metrics), for the operator at the gateway's own address; it carries no grant |
/metrics holds the requests by resource, method and status (wai_ingest_requests_total), the
sessions running by protocol (wai_ingest_sessions: WHIP, Enhanced RTMP and contribution publish
in, an RTMP connection counting once its publish is admitted; WHEP sessions are the gateway's
fan-out), the WHIP and WHEP sessions opened, the requests refused, the session records signed,
and wai_ingest_energy_unmetered, 1: the gateway's own energy in every record it signs is the
unmetered marker, since no meter backs it. No room, principal, grant, session or address is a
label.
Every request but OPTIONS and the operator's /metrics carries Authorization: Bearer <token>.
The token is a room grant: a WAI WRG1 record (live-rooms.md §4), base64url without padding.
A grant is public, so every request that carries one also carries a proof of possession of its key,
WAI-Room-Proof (live-rooms.md §10.5.3), over a single-use challenge the gateway gave in
WAI-Room-Challenge: on a 401 and on each response to a request with a grant. Refusals are
RFC 9457 problem details whose reason member is live-ingest.md §14's code.
Admission
The gateway holds each room's signed descriptor (WRD1) and checks a token against the
room it names, as the relay checks a token against its grants, here by the room's own
signed records: the grant reads and its signature verifies under the room's authority
(live-rooms.md §4.3, its field rules, its fourteen-day bound, its role and the room's
ceiling), it is good now, it is not among the room's revocations, its origins include the
gateway's, a single-use grant has opened no session here, and the request's proof passes
live-rooms.md §10.5.4 over a challenge held for its endpoint or session
(joule_moq::grant_proof::check_proof, through gateway::check_http_proof). What fails is 401 with
WWW-Authenticate: Bearer error="invalid_token". A good grant without the power the
request needs is 403 with error="insufficient_scope" (RFC 6750 §3.1): the publish
power for each media kind a WHIP offer carries, the subscribe power up to the layer a WHEP
request asks for. A session's resource answers only the token that opened it.
room.rs reads descriptors and grants from the extension's text; tests/room_corpus.rs
holds it to WAI's corpus wai/live-conformance/rooms/: every room id and grant digest,
the registered profiles' records, and every refusal of a descriptor or a grant there, but
an exchanged grant's link and the key log, which a bearer token does not bring. It also
runs the corpus's six HTTP proofs through check_http_proof, each with its stated
outcome, and presents each accepted proof again as a replay.
WHIP into the room
-
Tracks. Per media kind of the offer,
(room, owner, audio|video)/0and its receipts track0_receipts; and the owner's catalog,(room, owner)/catalog, withcatalog_receipts. All are published (PUBLISH) before the answer goes back. Audio and the catalog at publisher priority 0, video at 1. -
Frames. str0m depacketises RTP into frames: H.264 (RFC 6184), VP8 (RFC 7741), VP9 (RFC 9628), AV1 (its RTP payload format v1.0.0) and Opus (RFC 7587). Each frame is one object, one
WAI1envelope:codec capability payload H.264 wai.video.avcone access unit, Annex B VP8 wai.video.vp8one frame in IVF ( VP80), its size from the keyframe headerVP9 wai.video.vp9one frame in IVF ( VP90), its size from the uncompressed headerAV1 wai.video.av1one temporal unit in SPEC §5's AV1 framing, the temporal delimiter restored, the size from the sequence header Opus wai.audio.opus.packetone packet -
Groups. Video: one group per keyframe (a PLI goes to the publisher before the first one, and when a group passes
max_video_group_ms). Audio: one group per fixed window ofaudio_group_mson the room clock. One subgroup stream per group, written as the frames arrive. A track's first group ID is its first frame's room-clock time in microseconds. -
Time. The manifest's
livemember carries the frame's room-clock timet, its RTP time and clock rate, whether it is a keyframe, and on a group's first object the grant reference (live-rooms.md§4.5). The mapping is anchored at a track's first frame's arrival,t = A + (R − R0) · 10^6 / rate, and re-anchored at any frame it would place more thanmax_skew_msfrom its arrival: so every frame'stlies withinmax_skew_msof its arrival at the gateway. -
Receipts. When a group ends, the gateway signs its group receipt over every object and publishes it with the object receipts on the receipts track, chained to the group before. Every figure is the unmetered marker: no meter backs the gateway. The chain's alias is derived per session, so a publisher that reconnects starts a new chain.
-
The catalog is MSF JSON with WAI's
wai_*fields, published once every track has begun (or a second after the first did) and again whenever a codec or picture size changes, and signed like the media, so a relay that checks every track of the room at its door forwards it. -
The end. DELETE (or ICE lost, idle, a bound passed) ends each open group, publishes its receipts, waits for the relay to acknowledge every stream, and sends PUBLISH_DONE
TRACK_ENDEDon every track: the relay's subscribers see the tracks end.
WHEP out of the room
The gateway reads the owner's latest catalog once its receipt verifies, answers the
player's offer with the codecs the tracks carry, and subscribes to each accepted track and
its receipts track from the start of the latest group (the live part from the Next Object,
the rest of that group by a fill), so the player starts at a keyframe. Before a frame
reaches the player, its group's receipts must name its MOQT group and Object ID and the
track's chain, verify under a trusted first hop's key (whep.trust; this gateway's own
key by default), chain to the group before, and prove the object's inclusion; the object
must open as an envelope of the track's codec. What fails is dropped and counted in the
session's record; a group whose receipts never come is dropped after hold_ms.
What a WHEP player cannot see: the receipts. WebRTC carries media only. The gateway verifies on the player's behalf and records what it dropped and why; a WAI-aware player subscribes to the same tracks and their receipts tracks over MoQ, through the relay's WebTransport or WebSocket paths, and verifies every object itself.
A verified group is released when its receipts arrive, at the group's end, so a WHEP player is up to a video group behind the publisher.
What the player's sink dispatches first (live-ingest §9.5). A WAI-aware player writes in
its offer, as SDP capability attributes (RFC 5939, RFC 6871), the WAI capabilities its sink
dispatches, in its order. The gateway reads them with WAI's reference reader (sdp_caps,
wai-rs's src/sdp_caps.rs compiled here from its source) and forwards, per kind, the owner's
rendition the first of them names at or below the grant's max_layer: it answers that
configuration, its payload type alone in the section with a=acfg. Where nothing advertised is
published, the floor, the layer the resource names. An offer with none is answered as before,
byte for byte; so is one asking for what this revision does not negotiate
(caps_unsupported), with a=csup; every other reason of §9.5 is 422. The session's record
keeps the choice under detail.caps.
Enhanced RTMP into the room
- Admission. An encoder has a server URL and a stream key, and cannot answer a
challenge, so the publisher first POSTs to
/rtmpwith its grant and a proof of possession, admitted as a WHIP request is, and gets a stream key: 128 random bits, good for onepublishwithinstream_key_ttl_s(60 s). Thepublishcommand's stream name is the key; the grant is admitted again when it is used. A refusal isonStatusNetStream.Publish.BadNamewith the reason as its description. - The connection (
rtmp::chunk,rtmp::amf0,rtmp::session): the simple handshake, the chunk stream with its extended timestamps, Set Chunk Size, Abort, acknowledgements and pings, and the commands. Theconnectresult declarescapsEx0x0F and the FourCCs it carries. - Tracks (
rtmp::tracks,rtmp::flv): legacy AVC and AAC, andavc1,hvc1,av01,vp09,vp08,Opus,fLaCandmp4a, through ModEx and multitrack bodies and aggregate messages. Each RTMP track is bound to a room track at its first packet: under a grant with a layered video profile, the layer itsonMetaDataentry's size and frame rate match; audio track 0 only. Each frame is one object: Annex B with the record's parameter sets before a key access unit that carries none, the AV1 framing with the sequence header, IVF for VP8 and VP9, ADTS for AAC, a FLAC stream.live.rtpis the decode time in µs (rate1 000 000) andlive.ctothe composition offset; §7's mapping givest. - RTMPS on
rtmp.tls_listenwith a PEM chain and PKCS #8 key (tokio-rustls on the workspace's rustls and ring). - Shutdown. A publisher that declared
Reconnectis sentNetConnection.Connect.ReconnectRequest(withrtmp.reconnect_urlas itstcUrl, if set), its key is good once more, and the session ends when it leaves or afterreconnect_grace_ms. - Records. Each publish ends with a session record (
protocolertmp) whosedetailcounts what was read and not carried, by reason.
SCTE 104 into the room's cues
scte listens on injector.listen (SCTE 104's port is 5167) for one automation system at a
time: init_request, alive_request, and multiple_operation_message()s of splice,
time-signal and splice-null requests with avail, DTMF, segmentation, time, tier and private
descriptor requests. Each is answered (inject_response, then inject_complete_response
once its cues are signed) with SCTE 104's result codes. scte::scte104::translate builds each
SCTE 35 section (scte::scte35) on the room's 90 kHz clock and the cues it yields;
scte::Engine holds each cue until its splice instant, applies cancels and early returns,
drops what live-ads' break rules would refuse, and signs the cue as a cue event of the
injector's principal after its injection record (WIJ1, a meta event carrying the message,
its arrival and the translation's parameters). The events go out on the principal's events
track at the relay, published from the injector's start. The injector's grant must name its
key and permit cue and meta.
A relay whose door checks receipts names the room's media kinds in its rules
([room, "*", "audio"], [room, "*", "video"]): an events track carries no receipts.
Bounds
Each is a field of [limits], [groups], [timeline] or [whep] in the configuration:
| field | default | past it |
|---|---|---|
max_whip_sessions, max_whep_sessions |
64, 256 | 503 with Retry-After |
max_tracks_per_session |
2 | 422; and one track of each kind at most |
max_bitrate_kbps over bitrate_window_ms |
8 000 over 2 000 ms | stated per section as b=AS in the answer (a grant's publish profile lowers it); a session past it is ended |
max_frame_bytes |
4 MiB | the frame is dropped and counted |
max_queue_bytes |
32 MiB | the session is ended (relay_backpressure) |
audio_group_ms, max_video_group_ms |
200, 2 000 | — |
max_skew_ms |
250 | the track is re-anchored |
whep.hold_ms |
5 000 | the group is dropped (receipt_missing) |
rtmp.max_sessions |
64 | one more connection is closed at accept |
rtmp.max_message_bytes |
8 MiB | the connection ends (message_too_large) |
rtmp.max_bitrate_kbps over bitrate_window_ms |
40 000 over 2 000 ms | the publish ends (bitrate_exceeded) |
rtmp.connect_timeout_ms, rtmp.idle_timeout_ms |
15 000, 20 000 | the connection ends |
rtmp.stream_key_ttl_s |
60 | the key is refused (stream_key_expired) |
injector.max_pending |
256 | a message is answered 124 |
gateway.example.toml shows every field. It holds no secret: the relay token and the
signing key are files, and a room is its public, signed descriptor.
wai-ingest --config gateway.toml # JOULE_MOQ_INGEST_LOG sets the log level
Every listener is loopback by default: put a TLS front before the HTTP resources (RFC 9725
§5) and set media.bind_ip to an address clients reach. /metrics is the operator's: a request
that came through a front, one carrying X-Forwarded-For or another of the fields a front sets, is
answered as a path the gateway does not have, and a front that sets none of them is configured not
to pass the path on. Read at the gateway's own address, it carries no CORS field.
The WebRTC stack
str0m 0.25.0, pinned, MIT OR Apache-2.0, with
default-features = false and its rust-crypto backend: DTLS by str0m's own dimpl
0.9, SRTP and the rest on RustCrypto, whose elliptic curves (p256 and p384 0.14) run on
crypto-bigint 0.7. The stack builds one C library, aws-lc: each session's self-signed DTLS
certificate is made by rcgen on aws-lc-rs, which dimpl's certificate feature takes. It
is sans-IO: each session here owns a UDP socket and drives its Rtc from a tokio task,
feeding it datagrams and the time and draining its output after every change. It
depacketises and packetises H.264, VP8, VP9, AV1 and Opus at the frame level (AV1 is a
hidden codec in its public API; this crate's tests take AV1 through it end to end), supports
ICE lite and full ICE, ICE restarts, NACK and keyframe requests. Every crate new to the
lockfile is MIT, Apache-2.0 or ISC.
Uncompressed essence (SMPTE ST 2110)
WAI extensions/essence-contribution.md. The readers (st2110: the description, RTP and its
sequence, video rows into frames, PCM into blocks, ancillary data into records and the SCTE
104 messages in it) are in every build, with their corpus (wai/live-conformance/st2110/,
joule-moq-ingest-st2110-vectors --out|--check). The session is built with the feature
st2110, which brings the encode stage and the one encoder the crate links (rav1e,
BSD-2-Clause, without its assembly: the fallback); the real-time encoders are loaded at run
time and are no build dependency:
| resource | what it does |
|---|---|
/st2110 |
POST with the grant and its proof and {"sdp": "<the description>", "source": "<a capture's digital source type, optional>"}: 201, the session and, for each stream, the UDP port to send it to, its clock class and its TSMODE. Refusals: a description's own reason (sdp_*, 422), essence_streams_unsupported, essence_format_not_carried, essence_outside_floor, multicast_not_permitted, session_conflict |
/st2110/s/<id> |
DELETE ends the session |
A whole frame goes onto the video floor as wai.video.av1; a frame with a sample missing,
or one that found the encode stage's queue full, is counted and not published. Sound goes
out as wai.audio.flac, every sample as it arrived. Each object carries its capture instant;
SCTE 104 messages in the ancillary data go to the injector; every other ancillary data
packet is counted as not carried. The session's record (protocol st2110) holds each
stream's statement and every count, the encoder and its stage's counts, and an origin claim
a track where a source was stated. The gateway holds no reference clock and claims no
lock. [st2110] in gateway.example.toml lists the settings; a multicast group is joined
only with multicast = true.
The encode stage
st2110::encode: one stage ([Stage]) and one trait ([Backend]) with three encoders
behind it, chosen by [st2110] encoder and probed when the gateway starts.
encoder |
what encodes | where it comes from |
|---|---|---|
va |
the GPU's AV1 encode engine through VA-API (libva.so.2, loaded at run time; MIT), on the render node va_device |
the host's driver; Linux |
svt-av1 |
SVT-AV1 in its real-time mode (libSvtAv1Enc.so.4, or the path svt_av1_library, loaded at run time; BSD-3-Clause-Clear with the AOM Patent License 1.0). The adapter holds the layouts of 4.2 and refuses another version |
the operator's build of it |
rav1e |
the pure-Rust encoder this crate links, at its fastest preset, with tiles cut for the host's threads | every build: the fallback |
auto |
the first of those, in that order, that passes its probe |
- Asked for and not here is a refusal. With
encoder = "va"or"svt-av1"on a host without it, the gateway does not start and says why. Withencoder_fallback = trueit starts on the next encoder and says so in its log, in each session's answer (encoder:backend,asked,fallback) and in each session's record. No encoder runs under another's name. - The probe. Each candidate encodes a few computed pictures at 8 and at 10 bits; its
first temporal unit must hold a sequence header within the floor (Main profile, Main
tier, level 4.1 or below) and state the picture's size. One that does not is refused
with what was found.
POST /st2110does the same at the stream's own size and depth before it answers (essence_encoder_refused), and every keyframe of every session is held to the same check: a session whose encoder leaves the floor endsencoder_outside_floor, that unit unpublished. - The picture's size. A hardware engine may code frames larger than the picture, to
its own block alignment: the one measured codes 1920 × 1082 for a picture of
1920 × 1080. The VA-API adapter states the picture's size as the render size in every
frame header (
encode::obuwrites the sequence header and the start of each frame header, which that interface leaves to the application, and reads both back from what the driver made); the stage refuses a stream whose keyframes do not state the picture; the record'sencoder.stagehaspictureandcoded_frame. - What the gateway says at start: the encoder, its version and where it was loaded
from, every probe's outcome, and how long computed pictures of 1280 × 720 and
1920 × 1080 took at its fastest setting on this host (
calibrate_ms; a start-up estimate, not a measurement of a stream). - The real-time budget. The stage runs on its own thread behind
encode_queueframes. It converts 4:2:2 to 4:2:0, asks for a keyframe everykey_interval_msof the stream's timestamps, times every frame against the frame interval, and moves the encoder along its rungs: faster when a frame takes more than 85% of the interval or two frames wait, straight to the fastest when a frame was dropped, and toward the better picture only after a hold with the queue empty and under 45% of the interval used. SVT-AV1's rungs are its presets fromsvt_av1_presetto 13, changed mid-stream with no keyframe (withsvt_av1_preset = 0the first is chosen for the stream: 9 up to 1280 × 720 at 30 frames a second, 11 up to 1920 × 1080 at 30, 12 above);rav1e's are quantizers, each a new sequence; a hardware engine has one.encode_queue = 0is the frames of two fifteenths of a second, at least 4: a keyframe takes several frames' time, and the queue absorbs it. - The drop policy. A frame that arrives while the queue is full is not encoded.
Quality is lowered first. Every such frame is counted
(
not_published.frames_encoder_behind_not_published, and the stage'sframes_not_encoded_queue_full), and no encoder here drops a frame of its own. - The loops.
st2110::convert: 4:2:2 pgroups at 8 and 10 bits into planes, a word-at-a-time reader for every other pgroup, and chroma at half height by the rounded mean of two rows; each held bit for bit to a reference that says the same a sample at a time, at every shape. - The receive buffer. Each stream's socket is asked for
receive_buffer_octets, halving the ask while the host refuses it; the host's limit bounds what it gets (net.core.rmem_maxon Linux,kern.ipc.maxsockbufon macOS), and the session's answer and record state it, the record in time at the stream's rate too. A 1920 × 1080 stream at 30 frames a second is about 109 000 datagrams a second, at 60 about 218 000: a default buffer holds under a millisecond of them. - The way in (
st2110::rx). Each stream is read by a thread of its own that does nothing else, into batches through the session's one bounded queue. On Linux onerecvmmsgreads up to 64 buffers,UDP_GROlets the kernel hand over a run of datagrams of one size as one buffer (cut back here at the size it states),SO_TIMESTAMPNSstamps each andSO_RXQ_OVFLcounts the buffers a full one dropped. Elsewhere onerecvmsga datagram withSO_TIMESTAMP; on macOS the thread asks to be favoured (QOS_CLASS_USER_INTERACTIVE). The readers, and so the sequence, loss and completeness rules, are unchanged. The system calls are inst2110::sock, each with its SAFETY note. - Arrivals against the sender's type (
st2110::timing). Where a video stream's description names an ST 2110-21 type (TP), its arrivals are read against that type's Network Compatibility Model and the record counts the frames outside it; it is a reading at the gateway's socket, not the sender's compliance (sender_type_checkedstays"no"). - The test sender (
st2110::pace): ST 2110-21's linear schedule, four packets at an instant and never sooner than the model drains them, bysendmmsgwithUDP_SEGMENTon Linux and onesenda datagram elsewhere.tests/essence_rx.rsholds the way in to 1280 × 720 at 30 and 1920 × 1080 at 30 and 60 frames a second without loss, on request.
examples/st2110_profile.rs prints where a frame's time goes on the host it is run on
(reader, conversion, encode, packaging). tests/essence_rt.rs holds a real session to its
frame rate: 1280 × 720 and 1920 × 1080 at 30 frames a second for 20 seconds with each
real-time encoder the host has, failing on one frame dropped behind the encoder, and
refusing to measure on a loaded host. Every temporal unit is decoded by the host's libdav1d
(libdav1d.so.7, loaded at run time; BSD-2-Clause) and held to the picture sent, and the
first frames a second time by wai-av1, this repository's own decoder, sample for sample
against the first decode. What each encoder held on which host, dated, is in the
extension's §12.
The telephony bridge (SIP and RTP)
WAI extensions/telephony-bridge.md. The readers and the user agent's answers (telephony:
SIP messages, digest authentication with MD5 written from RFC 1321, offers and answers, RTP,
G.711, telephone events, the order and form of every answer) are in every build, with their
corpus (wai/live-conformance/telephony/, joule-moq-ingest-telephony-vectors --out|--check).
The bridge is built with the feature telephony and started by wai-ingest where
[telephony] enabled = true; it links nothing the crate did not already have.
- One peer. A SIP trunk or a PBX at
peer, over UDP, TCP or TLS (sip_udp,sip_tcp,sip_tls; port 0 takes one the host gives, and the bridge logs it). Requests from any other address are dropped and counted. The bridge's own requests go to the peer over UDP or TCP. A dialog'sContactis the listener of the transport it was made over (;transport=tcpover TCP, asips:URI over TLS), so the peer's requests in it come back the same way. - A call into the room. A number maps to grants (
[[telephony.number]] grants), or to PIN entry (pin = true, then[[telephony.pin]], the PIN read from a file). The call publishes one audio track of the grant's principal: G.711 aswai.audio.flac(every character's sample, 20 ms an object, 100 ms groups), Opus aswai.audio.opus.packetas it came, each object stamped with its capture instant, every group receipted as the first hop. - The room back. Each room's mix subscribes to the tracks its calls hear (the other calls,
and
hear_owners), verifies every object against its receipt, decodes FLAC at 8 kHz, and every 20 ms sends each call the sum less its own, in the call's law. - Placing a call and registering.
Bridge::place_calldials the peer; with[telephony.outbound] register = truethe bridge registers and keeps its registration. - The record of each call (protocol
telephony): its statement, its RTP counts by reason, the jitter buffer's, what it heard of each track, its origin claim wheresourceis set. No record says who called unlesscaller_in_record = true; none holds a PIN or a password.
tests/telephony_bridge.rs runs on loopback with the tests' own SIP peer and RTP callers
(tests/common/telephony.rs): two calls hearing each other through the room, sample for
sample, their tracks verified at a relay subscriber; credentials, a replayed digest and a PIN;
the planted faults over the wire, among them a call from an unconfigured peer, each with its
reason and the call going on after it; Opus carried as it came; calls over TCP and TLS; a call
the bridge places, challenged, and its registration. tests/telephony_rt.rs (ignored unless
asked for) holds one call to real time for 30 seconds both ways and carries 64 calls at once,
the default max_calls.
tests/telephony_interop.rs (ignored unless asked for) holds the bridge to an outside SIP user
agent: baresip 4.13.0 with libre 4.13.0 (BSD-3-Clause), built from their pinned sources and
named by TELEPHONY_BARESIP (WAI decisions D58 has the hashes and the build). It refuses to run
unless loopback is its only network interface: run it in a namespace of its own, as its header
shows. Three calls: the softphone calls in over UDP and over TCP (a PIN entered as its own RFC
4733 events), answering a SHA-256 digest challenge, and is called by the bridge; each time its
sound is its track, verified sample for sample, the room's other caller hears it exactly, and
it hears the room.
SRT and RIST
| resource | methods |
|---|---|
/srt |
POST with the grant and its proof: 201, a one-time session as JSON: its stream_id, passphrase, pbkeylen, the listener's latency_ms, host and port. With {"call": "ip:port", "passphrase": …}, the gateway calls the publisher's SRT listener, where [contrib.srt] call_allow lists it |
/rist |
POST with the grant and its proof, `{"profile": "simple" |
/srt/s/<id>, /rist/s/<id> |
DELETE ends the session, or one not yet connected; GET, HEAD |
The SRT listener ([contrib.srt] listen) checks each caller's stream ID
(#!::r=<room>/<owner>,m=publish,s=<session>) against the sessions it gave, and refuses with
the codes of live-ingest §13 (1401, 1402, 1403, 1404, 1405, 1409) and the draft's (1010 for a
wrong passphrase, 1011 for none). A RIST session's port takes the first flow whose RTCP CNAME
is the session's. The link's transport stream is demultiplexed: the first H.264 or HEVC
stream and the first AAC stream go to the video and audio tracks as WHIP's frames do, one
access unit (one ADTS frame) an object, the PTS on the room clock; a PES missing a packet is
dropped whole. The catalog declares the owner's link track.
The link record (linkrec, WLK1): every [contrib] record_interval_ms and when the
session ends, the gateway signs a part: the sequence numbers passed, each delivered at the
first try, recovered, dropped or outstanding, the loss runs, requests, retransmissions, round
trips and recovery times, chained to the part before and naming each media track's receipt
chain head. Each part goes out on the link track with its receipts, is kept
(Gateway::link_records) and is appended to [summary] link_out_path. The corpus
wai/live-conformance/links/ is written by joule-moq-ingest-link-vectors.
RIST is built only with the feature rist (joule-contrib's README, "Patents").
The session record, and live metering
Each session ends with a record of what it carried, signed by the gateway's key
(record.rs, format joule-moq-ingest/session/1): per track and direction the objects and
bytes, the drops by reason, subscriber sessions and their time by layer class, the grant
with its ceilings and the bytes under it, and the gateway's energy as the unmetered marker.
Gateway::records keeps them and summary.out_path appends them as JSON lines.
These are the counts of the per-hop session record WMH1 of WAI's live metering, kept in
its shape, role 3 (ingest gateway). Once that record lands, a record::HopSink that writes
WMH1 turns each record into its track entries, subscriber time and ledger entry and signs
it with the same key, which the room's key log lists under live/ingest; nothing else in
the gateway changes.
Tests
All on loopback, every wait bounded, the relay checking every receipt at its door:
| test | what it shows |
|---|---|
whip_publish |
A WHIP publisher (str0m as the client) sends three seconds of H.264 and Opus. A subscriber at the relay receives every group of both tracks, verifies every receipt under the gateway's key and every chain link, and gets the frames' bytes as sent; one group per keyframe, every audio group within its window; DELETE ends the tracks with PUBLISH_DONE; the session's record verifies. |
whep_play |
Before the publisher is live a WHEP POST is 409 with Retry-After. Then a WHEP player (str0m) gets the publisher's frames, byte for byte, from the keyframe of the group it joined to the last group closed; the WHEP session ends with the tracks, nothing refused. |
whep_caps |
An Enhanced RTMP publisher sends AV1 at layer 0 and H.264 at layer 1 (the camera-720 profile) with Opus; WHEP players state their sinks' capabilities. H.264 first: the answer is its configuration, a=acfg and one payload type, and the player gets layer 1's frames byte for byte from a keyframe. AV1 first: layer 0 in AV1. No attributes, and a required option the gateway does not support: the floor, no a=acfg (the second with a=csup). Attributes that do not hold together: 422 with the reason. Each record keeps the choice. |
auth_and_ice |
No token 401; a token that is not a grant 401 invalid_token; a viewer's grant 403 insufficient_scope; a grant past its window, one of another room; 415; 422; WHEP without subscribe or above max_layer 403; discovery and CORS. PATCH without If-Match 428, stale 412, trickle 204, another principal's grant, its own key proved, 403; a PATCH or DELETE presenting the grant without a proof 401 pop_missing; an ICE restart (If-Match: *) 200 with new credentials and a new ETag, ICE connecting again, and every frame before and after it at the relay. |
codecs |
VP8, VP9 and AV1 each through WHIP: every frame whole, one group per keyframe, the size each framing states. |
room_corpus |
The room reader against wai/live-conformance/rooms/, and its six HTTP proofs of possession through the gateway's proof step, each accepted proof also refused as a replay. |
ertmp |
A publisher of our own over RTMP and RTMPS: legacy AVC and AAC; enhanced HEVC with composition offsets and Opus; AV1 with FLAC and VP9 with AAC, a ModEx nanosecond offset; multitrack layers bound by the grant's profile; every refusal of a stream key; the reconnect request at shutdown. Every frame reaches a relay subscriber in its payload framing, at its mapped time, every receipt verified. |
scte104_injection |
An automation system of our own over TCP: init, alive, a second connection refused 110, splices with and without pre-roll, a cancel, time signals, refusals with their result codes; the chain verifies and every cue is its message's translation; a relay subscriber reads the chain from the events track. |
conformance_corpus |
wai/live-conformance/ertmp/ and wai/live-conformance/injection/ regenerate byte for byte; the texts' reason tables list the codes reported. |
ertmp_ffmpeg (ignored; --ignored where a local encoder is present) |
A local encoder as the test client: AVC with B-frames and AAC, HEVC and AVC on the platform's media engine, HEVC with Opus, AV1 with FLAC, VP9 with Opus; every frame decoded from what the relay carries. |
contrib_srt |
An SRT publisher, through a path that drops datagrams each way, into the gateway: a relay subscriber gets every H.264 access unit and AAC frame, every receipt verified; the link record's parts verify as a series, show the losses recovered and name each track's receipt-chain head as the subscriber found it, and are on the link track. Every listener refusal with its code; the gateway calling an encoder's listener with HEVC; 20 Mbit/s with groups of megabytes through the relay's door. |
contrib_rist (feature rist) |
A RIST Simple Profile flow and a Main Profile tunnel under PSK into the gateway, received whole; another CNAME opens no session. |
shutdown_ports |
From a task on a runtime of one worker, the gateway shut down and started again on the same ports many times: when the shutdown returns, its HTTP, RTMP and SRT ports and a RIST session's ports (waiting or running, feature rist) bind at once, the HTTP connection it kept alive and an RTMP connection mid-handshake are closed, and the SRT and RIST sessions that ran have signed their records. A RIST session whose relay does not answer its dial signs its record, gateway_stopped, and its ports bind at once; so do a RIST listener's held by a task the shutdown ends past its bound. |
start_ports |
From a task on a runtime of one worker, a start on fixed ports refused part way (the RTMP, RTMPS, SRT or SCTE 104 port held, or the RTMPS identity spoiled): when it returns, every other port binds at once, and a start with nothing held comes up on all of them. |
link_corpus |
Every vector of wai/live-conformance/links/ with its stated outcome. |
contrib_interop (ignored) |
The reference SRT caller and RIST sender into the gateway, with an encoder's H.264, HEVC and AAC through lossy paths (tools named by WAI_SRT_LIVE_TRANSMIT, WAI_RISTSENDER, WAI_FFMPEG, WAI_FFPROBE). |
contrib_bench (ignored) |
The gateway's throughput and energy on an SRT link, the sender in a process of its own. |
Not implemented
vvc1 over Enhanced RTMP; a stream key another gateway accepts after a reconnect request;
SCTE 104 in a video signal's ancillary data (cue-injection.md §10); SRT and RIST egress; a
WHEP counter-offer;
a player's keyframe request carried upstream; publishing into a slot; simulcast within one
WHIP session; STUN and TURN in Link headers; reading the key log itself (revocations are
the list a deployment configures).
Licence
Apache-2.0.