AES67 (Audio over IP protocol) resources

AES67 is a standard for audio over IP developed by the Audio Engineering Society. It enables interoperability between existing standards such as Dante, RAVENNA, Q-Lan and Livewire.

Information about AES67

So how does AES67 actually work? The AES67 Wikipedia page and the AES67 draft from 2017 are a good point to get an overview:

• Wikipedia AES67
• AES Standard draft (2017) ,  archive

In summary AES67 consists of three major, already existing standards. The first is IEEE 1588-2008 ( Wikipedia ) for clock synchronization. The second is RTP ( Wikipedia ) as the transport protocol with 24-bit PCM as the default audio format transmitted via multicast. The third is SDP with SAP as the transport protocol for session discovery. I suggest to read the standards (sadly IEEE 1588-2008 is behind a paywall) if you want to know how they work, as I won’t be explaining any details here.

Implementations of the standards

As the mentioned important standards for AES67 already exists longer than AES67 itself. We do not necessarily need to implement them, as there are already good working implementations out there.

RTP

• GStreamer (also implements PTP and SDP)
• ffmpeg
• rtptools

PTP

• ptpd
• linuxptp
• philhartung/node-ptpv2

SAP/SDP

• clux/sdp-transform
• pixelbender/go-sdp

Open source software

There is already some open source software for AES67 out there. Open source projects that are related to AES67 which I find most interesting are (in no particular order):

• voc/aes67-recorder : AES67 multitrack recording software developed by the CCC VOC
• markmcconnell/mai : JACK AES67 virtual soundcard
• bondagit/aes67-linux-daemon : Alsa virtual soundcard based on the Merging AES67 Alsa driver
• njh/mast : Multicast Audio Streaming Toolkit compatible with AES67
• martim01/pam : “Open Source Audio Monitoring Software designed for (but not limited to) a Raspberry Pi with touchscreen.” Supports AES67 based streams.
• ebu/pi-list : Tool to analyse packet captures for SMPTE 2110 compliance.
• GStreamer : Multimedia framework that implements RTP and PTP, and is thus able to receive and generate AES67 compliant RTP streams. The before mentioned aes67-recorder is based on GStreamer. To see how to use GStreamer with AES67 you can take a look at the following examples: AES67 to Icecast relay , listen to AES67 stream , relay AES67 to a different subnet or sync GStreamer to PTP master .
• “convert” a Dante multicast stream to AES67 This is a proof of concept by myself. Might still be interesting for people, who want to use Dante VSC (which does not support AES67) with AES67 receivers.

Closed source software

• Lawo VSC  (Windows) AES67 virtual soundcard
• Lawo Stream Monitor  (Windows) AES67 stream monitoring tool
• Merging ALSA Driver  (Linux, free and partially open source) AES67 Alsa virtual soundcard
• Merging MacOS VSC (MacOS, free) AES67 virtual soundcard
• Livewire+ VSC (Windows) Livewire+ virtual soundcard, compatible with AES67
• Ravenna VSC  (Windows, free) Ravenna virtual soundcard, compatible with AES67
• RAV2SAP  (Windows, free) “Session announcement translation between RAVENNA and SAP-based systems”
• PTP Track Hound (MacOS, Linux, Windows, free) PTP network traffic analysis tool
• Aneman (MacOS, Windows, free) Cross platform and cross vendor AoIP connection manager

Discussion, talks, articles and other resources

• Audio over IP Google mailing list: A place for users and Software Developers to discuss Audio over IP topics
• https://www.youtube.com/watch?v=DaMBI3WZkCY : Short talk about how AES67 was used on the 35c3 . Slides of the talk can be found here
• AES70 resources : AES70 or Open Control Architecture ( Wikipedia ) is a standard, to manage, control and monitor AoIP devices. The standard consists of three parts ( Part 1: Framework , Part 2: Class structure , Part 3: Protocol for TCP/IP Networks ).
• Connecting Dante devices to AES67 : This article is for Yamaha devices, but the information also applies other Dante devices, that support AES67
• Receiving AES67 audio on the command line : Interesting article about receiving AES67 streams with rtpdump and SoX

If you have further suggestions of software or resources that are missing on this list, feel free to contact me on Twitter .