Delay in Audio on the Telos Alliance xNode
Updated
by
Werner Gabel
Scope/Problem
Routing a source by Livewire to a destination on the same xNode there will occur some audio delay. This kind of audio delay will not appear on any different physical output anywhere else in the network; only the local node the source comes from.
Description
If we do route a source by Livewire to a destination on the same xNode there will be some delay. Probably more delay that could be tolerated if you are execting to monitor this in Headphones.
A limit of IGMP (Multicast) is that a device that produces a multicast stream (a Livewire source) can not also subscribe to it. This is not a limit of the Telos Alliance xNode but with multicast in general. In the xNodes (and other Axia products) we treat this as a special case and any "looping" of audio must be done in the CPU which is not a real-time OS.
Solution / Work-Around
In case you need to "loop" audio within the same Telos Alliance xNode you need to do it in the build-in Vitual Mixer.
Below, please find a very simple example in case of need. Here we do mix Line Input 1 to the Line Output 1. Using the build-in Virtual Mixer of the xNode and not Livewire channels, there is zero delay because the looping is actually happening in the FPGA hardware of the Telos Alliance xNode.
But if you are looping by using Livewire, the delay is expected.
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