RTP Voice Backend¶

The RTP backend sends and receives voice audio over RTP for integration with PBX/SIP gateways or any system that speaks RTP.

Install with: pip install roomkit[rtp]

Quick start¶

from roomkit.voice.backends.rtp import RTPVoiceBackend

backend = RTPVoiceBackend(
    local_addr=("0.0.0.0", 10000),
    remote_addr=("192.168.1.100", 20000),
)

See the full RTP example for a complete runnable script.

API Reference¶

RTPVoiceBackend ¶

RTPVoiceBackend(*, local_addr=('0.0.0.0', 0), remote_addr=None, payload_type=0, clock_rate=8000, dtmf_payload_type=101, rtcp_interval=5.0)

Bases: VoiceBackend

VoiceBackend that sends and receives audio over RTP.

Each :meth:connect call creates a new aiortp.RTPSession bound to the configured local address and sending to the remote address.

Inbound audio is decoded by aiortp (G.711, L16, Opus) and delivered as AudioFrame objects via the on_audio_received callback. DTMF digits are received out-of-band via RFC 4733 and delivered via on_dtmf_received callbacks.

Parameters:

Name	Type	Description	Default
`local_addr`	`tuple[str, int]`	`(host, port)` to bind RTP. Use port `0` for OS-assigned.	`('0.0.0.0', 0)`
`remote_addr`	`tuple[str, int] \| None`	`(host, port)` to send RTP to. May be `None` if supplied per-session via `metadata["remote_addr"]` in :meth:`connect`.	`None`
`payload_type`	`int`	RTP payload type number (default `0` = PCMU).	`0`
`clock_rate`	`int`	Clock rate in Hz (default `8000` for G.711).	`8000`
`dtmf_payload_type`	`int`	RTP payload type for RFC 4733 DTMF events (default `101`).	`101`
`rtcp_interval`	`float`	Seconds between RTCP sender reports.	`5.0`

send_transcription `async` ¶

send_transcription(session, text, role='user')

Log transcription text (no UI channel in RTP mode).

on_dtmf_received ¶

on_dtmf_received(callback)

Register a callback for inbound DTMF digits (RFC 4733).

Parameters:

Name	Type	Description	Default
`callback`	`DTMFReceivedCallback`	Function called with `(session, dtmf_event)`.	required

Capabilities¶

The RTP backend declares DTMF_SIGNALING (RFC 4733 out-of-band DTMF) and INTERRUPTION (cancel outbound audio mid-stream).

DTMF¶

Inbound DTMF digits are received via RFC 4733 and delivered as DTMFEvent objects. Hook into them with HookTrigger.ON_DTMF:

@kit.hook(HookTrigger.ON_DTMF, execution=HookExecution.ASYNC)
async def on_dtmf(event, ctx):
    print(f"DTMF: {event.digit}")

Per-session remote address¶

Pass metadata={"remote_addr": (host, port)} to connect() to override the remote address per session, useful for multi-tenant PBX setups.