An introduction to computer audio
AVB (IEEE 802.1BA) is part of the open standard IEEE 802.1 standard.
It allows for time-synchronization of endpoints and real-time, low latency delivery of audio/video.
As it is open it might get a broad support.
At the moment AVB is used in professional applications but it might come to the consumer world.
Ethernet AVB over Ethernet delivers:
- Sub microsecond time synchronization
Precise presentation times
- Guaranteed priority for AV traffic with:
- Stream reservation
- Zero data loss
- Low latency with <2ms packet delivery for class A traffic
According to Harman the advantages are:
- AVB is an open standard – there need not be license fees for a manufacturer to pay a third-party. This lack of royalty fees for an individual device results in total system cost reduction – often dramatically.
- AVB represents a change in the way the Ethernet network works. The AVB Ethernet switches on the network reserve up to 75% of the entire data bandwidth for media traffic. Nothing else can interrupt the audio and video data, and therefore the risk of any unwanted clicks and pops is eliminated.
- Audio and video data packets are transmitted from a source device with a ‘time-to-play’ stamp. This mechanism of clocking the network means that network latency is precise at all destination devices, multiple sample rates can exist and audio and video data remain perfectly in sync over the network.
- An AVB network can include devices and switches with 100MB, 1GB and in the future 10GB Ethernet and more, meaning it is truly future-proof.
AVB is part of Mac OS X from Yosemite on.
The AVnu Alliance is an industry forum dedicated to the advancement of professional-quality audio/video by promoting the adoption of the IEEE 802.1 Audio/Video Bridging (AVB), and the related IEEE 1722 and IEEE 1733 (which extends RTP for use on AVB) standards over various networking link-layers. The organization will create compliance test procedures and processes that ensure AVB interoperability of networked A/V devices, helping to provide the highest quality streaming A/V experience.
References
- AVnu Alliance
- Understanding Audio Video Bridging - Peter Hedinger, Andrew Lucas and Henk Muller | Electronic Design
- AVB - Audio Asylum
Products
Motu AVB switch US$ 295.00
AVB reserves bandwidth for its streams.
You need a AVB aware switch if you want to stream over the LAN.
Added 2016
Meyersound CAL. Active speaker with AVB input.
Motu Ultralite AD/DA converter
USB 2.0 (44.1 to 48 kHz): 64 in/out
USB 2.0 (88.2 to 96 kHz): 32 in/out
USB 2.0 (176.4 to 192 kHz): 24 in/out
AVB Ethernet: 16 to 128 in/out, depending on host computer speed
Added 2016
MiniDSP N-DAC8 US$ 299
8 channel network audio DAC over AVB, 8 analog RCA outputs.
Added 2016
References
AVnu Alliance
Understanding Audio Video Bridging - Peter Hedinger, Andrew Lucas and Henk Muller | Electronic Design
AVB - Audio Asylum