Special Feature | Audio Video Bridging
AVB standards, and many of these industry leaders also participate in the AVnu Alliance that promotes AVB development. Most estimates predict that in the near future, a majority of all Ethernet products will include an AVB-capable chipset.
Technical Details
AVB is composed of three basic standards: 802.1Qav, 802.1Qat and 802.1AS. The 802.1Qav standard specifi es the rules for the queuing and forwarding of data traffi c within the Ethernet network. Together, these rules serve to prevent bottlenecks at bridges and destinations. The 802.1Qat standard defi nes the stream reservation protocol. This protocol is responsible for the routing and bandwidth of the data stream through the IP infrastructure. It guarantees bandwidth for particular protocols within the Ethernet stream and prevents different protocols or data transfers from cancelling out one another. Finally, the 802.1AS standard allows exact synchronization — to the microsecond — to occur between all AVB nodes and thereby ensures that the exchange of data is possible in real time.
In addition to the separate standards for communication within an AVB system, the IEEE 1733 and IEEE 1722 standards defi ne how
actual media data is placed into individual data packets. 1722 is the underlying transport protocol defi ning the packet structure, and it is responsible for how audio and video signals are sent over the network.
“It defi nes the language, so to speak, that is spoken within the Ethernet network,” says Lee Minich, chair of AVnu Alliance’s marketing workgroup, in explaining 1722. An additional protocol that handles devise recognition, connection management between individual devices, and the allocation of individual devices in the network was completed in 2012.
In terms of widespread AVB adoption, it is true that in many places, it remains a standard of the future. Nevertheless, AVB is based on proven technology, and it is a practical reality — evident in current hardware development from the leading manufacturers of Ethernet technology. Next to crucial cost savings, especially with respect to installation costs, AVB offers exciting new possibilities. It has become a driving factor in the design of future systems for theaters, stages and fi xed installations. As theaters consider future network expansion or new installations, AVB opens the door to a host of cost-saving options for leveraging and building on existing cable infrastructures.
NOW THIS YOU JUST HAVE TO SEE
Made in the UK The Rx range
• MODULAR rack mount test and measurement • Video, audio, generation, analysis, 24/7 • A range of modules including eye and jitter • 3G-SDI, HD-SDI, SD-SDI and Optical support • Instrument multi-viewer at 1920 x1080 on HDMI • Simultaneous analysis/monitoring 8 SDI channels •16 channel embedded audio, Dolby E / AES support • Ideal for OB operation, low weight, low power • Cool in operation • Remote control
RX 500 4 channels
Hand held eye and jitter plus new Dolby E
generation and analysis The Sx range
PHABRIX SxA 3G-SDI, HD-SDI, Sd-SDI
PHABRIX SxD Dual link 350 Formats
PHABRIX SxE eye and jitter
RX 1000 8 channels
Loudness 2K formats AES module
RX 2000 Dual screen 8 channels
www.phabrix.com
info@phabrix.com tel + 44(0)1635 873030
ibeconnects.com | May/June 2013 | 45
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48