Page 18 - IP Audio for TV Production And Beyond

AES67 INSIDE
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The inclusion of AES67 audio transport in the new SMPTE ST 2110 standard is one more example of the rapid and widespread adop on of this standard in providing signal interoperability across all of the current leading IP based audio networking systems.
Wheatstone has been a supporter of this IP audio interoperability standard since the beginning, rst as a member of the AES X192 task force that formulated the requirements for AES67. In fact, Wheatstone’s solu on for stream discovery and connec on management is described in the appendix of the AES67 standard itself.
More recently, Wheatstone has been a full par cipant
in plugfests and tradeshow demonstra ons of AES67
in ac on. During the recent Houston InterOp plugfest sponsored by Video Services Forum (VSF) in August 2017, we successfully ingested IP audio streams into our WheatNet-IP Audio network BLADEs from a variety of di erent manufacturers via AES67.
The following month we met again with fellow vendors, and demonstrated AES67 compa bility as a par cipant in the IBC IP Showcase in Amsterdam.
We built AES67 compa bility into WheatNet-IP
audio networking products because we recognize the importance of this standard as a way to transport audio from, say, a broadcast group that might have one network pla orm (such as a WheatNet-IP system) and a remotely located produc on facility that has another (such as Dante).
What AES67 Does
Almost all audio networks use a standard IP protocol called RTP (Real-Time Protocol) to load con nuous audio data into a fragmented stream of IP packets. RTP provides iden ca on in the packets about their crea on me
and order but, prior to AES67, it has been up to the IP audio network manufacturer to embed and extract this informa on and to recreate the audio. Each di ers in
the speci c packet loading, ming and synchroniza on mechanisms within the protocol.
AES67 came along to provide the common synchroniza on, clock iden ca on, session descrip on and other interoperability recommenda ons we can all share. AES67 adopted the PTPv2 (Precision Time Protocol - IEEE 1588-2008) standard as the master clock reference, so we can transport audio between our various systems without data dropout from unmatched clocking.
What AES67 Doesn’t Do
While AES67 provides a common transport standard to move audio from one system to another, it does not specify discovery, stream management, and associated logic func ons for controlling devices on the network.
Turning devices on and o , controlling peripheral gear from the console, signaling when a source is ready for air play, and controlling the playout system with a fader channel – these are all func ons of WheatNet-IP and similar audio networks.
In the case of WheatNet-IP, for example, a single Ethernet cable carries the real- me audio stream as well as network and device control data cri cal to the daily opera on of a studio. l