Ethernet AVB (Audio Video Bridging) – in development

Ethernet has long been around as the major protocol for moving digital information across networks. With the advent of Giga-bit networks moving static information is now closer to a breeze. Nonetheless, the free flow of audio and video over Ethernet has yet to come. Issues of bandwidth and packet timing has so far stopped high bandwidth applications. Several competing protocols exist but they all have the drawback of being manufacturer and equipment specific and thus prohibitively expensive. This is where Ethernet Audio Video Bridging, or just AVB for short, is the near future solution according to the IEEE 802 working groups behind the project.

Ordinary Ethernet standard is based around the concept of delivering data without loss but not necessarily on time. As all of us have experienced when trying to surf over a slow Net connection, the data will arrive sooner or later but that’s usually fine for static things – files, browser pages, images and so on. When it comes to audio and video though the lack of timing inherent in the Ethernet protocol will lead to de-synchronization – the stream will glitch and the effects are anything from choppy sound and image to loss of data when the client application at the end gets confused. Another aspect of the lack of timing within the protocol is the inability to synchronize multiple streams within the network – a huge problem for delivering multi-channel audio and synchronized video.

The IEEE 802 is hoping to converge the needs of, on one hand, providing the means for low-latency syncronised audio and video streaming over existing networks which is sought for by content providers and router vendors, and on the other hand, the need from the professional media industry to deliver high-bandwidth, multi-channel audio and video for a variety of purposes, ranging from recording and post production processes to live concerts and broadcast.

AVB is promised to assure tight synchronization of audio and video streams coming across different paths – a necessity for the post-production process. By providing exact timings and ensure that there are resources along all the bridges in the path one will be able to develop equipment and processes that are well-synced. Finally, the new standard aims to pace traffic so that AV does not use up the entire bandwidth. 25% of the bandwidth is supposed to be reserved at all times for non-AV, standard Ethernet traffic.

If this standard gains wide support, and there are a number of manufacturers ranging from the automotive industry to professional audio already looking with an eager eye, the telecommunication vendors will have to upgrade hardware with new chips. While none of the big chip manufacturers seem open about their future plans in regards to AVB it is clear that they are following the development closely, and in the light of several audio manufacturers already promising AVB compliant network support for their next generation audio platforms, it seems just fair to assume that we may see more and more equipment based on Ethernet AVB towards the end of 2009.

Sources: EE Times Asia (Jan 2009), Embedded.com (Nov 2007)

More info on the topic: IEEE 802.1 AV Bridging Task Group

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Tags: 802.1, audio, audio network, avb, digital audio platform, digital network, digital standard, ethernet, ethernet avb, ieee, multi-channel audio, network, standard, video