Dual Streaming - Digigram aqord *link User Manual

6.4. Dual Streaming
Mission critical video transport
One objective of broadcasters while deploying their IP infrastructure is to achieve the robustness of synchronous
telecom or satellite networks on private leased lines while reducing significantly the corresponding production costs.
The experience gained from existing IP infrastructures proved that IP network disturbances are of a different nature
when occurring inside the Telco backbone infrastructure or during the "Last Mile" path (i.e. near/inside the
broadcasters premises).
So it is essential for the broadcaster to choose an appropriate operation strategy for each different type of transport he
will use, such as fully managed networks using QoS or "Best effort" networks (Internet, Wireless 3G/4G and Wifi).
AQORD encoders/decoders implement FEC (Forward Error Correction) and now "Dual Streaming" to secure the
transmission in order to meet Broadcasters and Telcos IP transport strategies.
At the source side, AQORD sends and carries the same Video IP stream on two distinct networks. Then on the
receiver side, it automatically synchronizes both received streams. The different IP paths followed on each network
ensures that the potential failures are statistically uncorrelated, enabling the reconstruction of an unique unperturbed
stream.
Benefits from AQORD permanent redundancy or "dual streaming" : Allows you to make use of an economical network
despite low QoS.
Limitations : ​ Obviously one needs two different and independent network links between encoder and decoder.
The decoder sets the size of its receiving buffer based on a set of measurements to take into account the delay
between the two links and the jitter of each of them, in order to minimize the size of this buffer and thereby minimize
the overall system latency.
"Dual Streaming" can be combined with FEC in order to increase transmission robustness.
Figure 8: "Dual Streaming" contribution