AES67

showstack / protocols / aes67

Also called AES67 audio-over-IP, AES-67.

An AES interoperability standard for streaming uncompressed audio over IP using RTP and IEEE 1588 PTP. It is the common ground that lets Dante, RAVENNA, Q-LAN, Livewire and Ravenna-derived broadcast gear exchange streams without a hardware bridge.

Audio transportPaid specAudio Engineering SocietyReported

Stewarded by Audio Engineering Society (AES).

Media Large, continuous, on time and in order

Continuous streams that are large enough to be sized properly, and that must arrive in order and on time.

What kills it. Anything that starves the link — usually a management transfer nobody scheduled — and jitter that outruns the receive buffer.

The four flows, and why the model is worth having →

Ports

udp/5004 RTP media stream (RTP/AVP default port)
Audinate documents 5004 for AES67 multicast audio from Dante devices. The actual port for any given stream comes from the SDP, so treat 5004 as the common default rather than a fixed rule.

udp/9875 SAP session announcements used for AES67 stream discovery
SAP is one of several discovery mechanisms in use. AES67 does not mandate any of them.

Multicast

AES67 streams are usually multicast but the standard does not reserve an address range, so the plant owner assigns it. Audinate's Dante devices emit AES67 flows in 239.69.0.0/16. SAP announcements go to 239.255.255.255:9875. AES67 specifies IGMP for managing multicast traffic.

What it carries

Sample rates: 48 kHz
Audio bit depth: 16-bit, 24-bit
Audio encoding: Linear PCM, L16 and L24

Audio: 48 kHz is the mandatory interoperability point; other rates may be supported but cannot be assumed between vendors. The same applies to packet time, where 1 ms is required and 125 microseconds is optional.

What goes wrong

AES67 mandates no discovery method at all. SAP, Bonjour/mDNS and NMOS IS-04 are all in the field. Two fully compliant devices can sit on the same switch and never see each other, and you patch by hand from the SDP.

It standardises the stream and the clock, not the ecosystem. There is no AES67 device control, no level control, no naming, no subscription model, so day to day patching still happens in each vendor's own tool.

AES67 is built on PTPv2 (IEEE 1588-2008). Dante's native clock is PTPv1, so a Dante device switched into AES67 mode changes clock domain and stops clocking with its non-AES67 neighbours.

A 1 ms packet time is the only one every AES67 device must support. 125 us, 250 us, 333.33 us and 4 ms are optional, and broadcast gear often defaults to a short one for latency. A receiver that only does 1 ms just refuses the stream.

An AES67 flow carries no channel names. Channel order in the stream is the only thing that identifies what is where, so document the map or you will be counting pairs at soundcheck.

What speaks AES67 (33)

33 products — 30 hardware, 3 softwareshow all

Product	Direction	Notes
Dante Controller Audinate	bidirectional	Configures AES67 mode on capable devices.
Dante Virtual Soundcard Audinate	bidirectional	AES67 mode where the network supports it.
Q-SYS Designer QSC, LLC	bidirectional	Cores stream AES67 as multicast alongside the native Q-LAN transport. QSC's capacity tables count Q-LAN and AES67 network channels together and list no separate AES67 feature licence.
Avid VENUE S6L-32D Avid	bidirectional	Through Dante in AES67 mode.
Biamp TesiraFORTÉ Biamp	bidirectional	AES67 mode on supported firmware.
BSS Soundweb London BLU-806 BSS Audio	bidirectional	Via Dante AES67 mode.
Cisco Catalyst 9200 Series Cisco	bidirectional	Transported, with the same QoS requirements as Dante.
Clear-Com FreeSpeak II Clear-Com	bidirectional	Where enabled.
d&b audiotechnik 40D installation amplifier d&b audiotechnik	bidirectional	Where enabled.
d&b audiotechnik DS100 Signal Engine d&b audiotechnik	bidirectional	AES67 mode.
DiGiCo Quantum 338 DiGiCo	bidirectional needs licence	Via DMI Dante card in AES67 mode.
DirectOut PRODIGY.MP DirectOut	bidirectional	Via module.
Ferrofish A32 Dante Ferrofish	bidirectional	Via Dante AES67 mode.
Focusrite RedNet A16R MkII Focusrite	bidirectional	AES67 mode.
Green-GO Digital Intercom Green-GO (ELC)	bidirectional	Depending on model and firmware.
L-Acoustics LA4X L-Acoustics	in	AES67 input on current firmware.
L-Acoustics LA7.16i L-Acoustics	bidirectional	Where enabled.
L-Acoustics P1 L-Acoustics	bidirectional	Where enabled.
Lab.gruppen PLM 20K44 Lab.gruppen	in	Via Dante AES67 mode.
Lab.gruppen Lake LM44 Lab.gruppen	bidirectional	Where enabled.
Luminex GigaCore 10 Luminex Network Intelligence	bidirectional	Transported.
Luminex GigaCore 16Xt Luminex Network Intelligence	bidirectional	Transported, listed alongside RAVENNA.
Luminex GigaCore 26i Luminex Network Intelligence	bidirectional	Transported.
NETGEAR M4250 (AV Line) NETGEAR	bidirectional	Transported, AV profile available.
Powersoft X8 Powersoft	in	AES67 input mode.
Q-SYS Core 510i QSC (Q-SYS)	bidirectional	Software AES67 streams for interop with other AoIP systems.
Riedel Bolero Riedel Communications	bidirectional	Networked audio.
RTS ADAM Intercom Matrix RTS (Bosch)	bidirectional	Where enabled.
Symetrix Radius NX 12x8 Symetrix	bidirectional	Where enabled.
Yamaha CL5 Yamaha	bidirectional	Via Dante AES67 mode on supported firmware.
Yamaha DM7 Yamaha	bidirectional	Through Dante interoperability.
Yamaha Rio3224-D2 Yamaha	bidirectional	Through Dante interoperability where enabled.
Yamaha RIVAGE PM7 Yamaha	bidirectional	Via Dante AES67 mode.