Add core RTP-over-WebSocket (rtpws) for AudioBridge WebSocket media

[mirkobrankovic82]

Summary

• Add Janus core rtpws listener for binary RTP over WebSocket (janus.jcfg rtpws section).
• Wire AudioBridge media=websocket joins to rtpws peer bindings and websocket_media.url.
• Honor the AudioBridge join codec (opus, pcma, pcmu, l16, l16-48) when creating the rtpws peer — call_info reports the negotiated codec, payload type, sample rate, and framing.
• Add L16 linear PCM support (l16 @ 16 kHz, l16-48 @ 48 kHz) on plain RTP and media=websocket; decode/encode big-endian slinear and restrict L16 joins to a matching room sampling_rate.
• Add optional per-participant ws_framing on media=websocket joins — rtp (default, full RTP packets, unchanged) or payload (raw codec payloads, no RTP header). In payload mode the core strips the RTP header outbound and synthesizes one inbound (monotonic seq/timestamp/SSRC), so external AI/STT/TTS clients can exchange plain codec bytes without parsing or emitting RTP.
• Include ws-audio-test Go CLI and shell wrapper for plain RTP / WS media validation (--codec selects opus / pcma / pcmu / l16 / l16-48; --framing selects rtp / payload; G.711 and L16 tone encoding).

Notes

• Requires --enable-websockets at build time.
• AudioBridge rooms need allow_ws_participants = true at create time (cannot be enabled later via edit).
• Clients must send RTP matching the server call_info (codec, PT, sample rate).
• l16 requires a room sampling_rate of 16000 and l16-48 requires 48000; mismatched joins are rejected.
• ws_framing is negotiated per join (no global config); payload framing pairs well with l16/l16-48 to hand STT/TTS providers raw 16-bit PCM directly.

Example (Opus)

go run . ws-stream   --janus-http http://127.0.0.1:8088/janus   --token "$TOKEN"   --room "$ROOM"   --duration 5s
23:23:56.642157 websocket_media.url = ws://127.0.0.1:8190/ws-audio?sid=5337f2ef-bd0a-42d2-ad7a-d7826889b5b7
23:23:56.971244 [ws-stream] connected ws://127.0.0.1:8190/ws-audio?sid=5337f2ef-bd0a-42d2-ad7a-d7826889b5b7
23:23:56.971895 [ws-stream] server: {"type":"call_info","codec":"opus","sample_rate":16000,"channels":1,"ptime_ms":20,"payload_type":100}
23:23:56.972449 [ws-stream] rx seq=1 ts=0 pt=0 ssrc=1372789150 (20 B)
23:23:57.542010 [ws-stream] rx seq=51 ts=48000 pt=0 ssrc=1372789150 (20 B)
23:23:58.543518 [ws-stream] rx seq=101 ts=96000 pt=0 ssrc=1372789150 (20 B)
23:23:58.973112 [ws-stream] tx=99 pkts (17028 B) | rx=122 pkts (2440 B) | rx_bad=0
23:23:59.543301 [ws-stream] rx seq=151 ts=144000 pt=0 ssrc=1372789150 (20 B)
23:24:00.542306 [ws-stream] rx seq=201 ts=192000 pt=0 ssrc=1372789150 (20 B)
23:24:00.972743 [ws-stream] tx=199 pkts (34228 B) | rx=222 pkts (4440 B) | rx_bad=0
23:24:01.544217 [ws-stream] rx seq=251 ts=240000 pt=0 ssrc=1372789150 (20 B)
23:24:01.995794 [ws-stream] tx=249 pkts (42828 B) | rx=273 pkts (5460 B) | rx_bad=0

Example (G.711 μ-law)

go run . ws-stream   --janus-http http://127.0.0.1:8088/janus   --token "$TOKEN"   --room "$ROOM"   --codec pcmu   --duration 5s
# call_info: {"type":"call_info","codec":"pcmu","sample_rate":8000,"channels":1,"ptime_ms":20,"payload_type":0,"framing":"rtp"}

Example (L16 / 16 kHz)

go run . ws-stream   --janus-http http://127.0.0.1:8088/janus   --token "$TOKEN"   --room "$ROOM"   --codec l16   --duration 5s
# call_info: {"type":"call_info","codec":"l16","sample_rate":16000,"channels":1,"ptime_ms":20,"payload_type":106,"framing":"rtp"}
# full RTP frames on the wire: 12-byte header + 640-byte L16 payload (320 samples * 2 bytes)

Example (payload framing, raw L16 for AI/STT/TTS)

go run . ws-stream   --janus-http http://127.0.0.1:8088/janus   --token "$TOKEN"   --room "$ROOM"   --codec l16   --framing payload   --duration 5s
# call_info: {"type":"call_info","codec":"l16","sample_rate":16000,"channels":1,"ptime_ms":20,"payload_type":106,"framing":"payload"}
# raw codec payloads on the wire (no RTP header): 640-byte L16 frames in and out