Contribution via the internet is tricky but has great promise. With packet loss and jitter all over the place, how can you deliver perfect video?
Ciro Noronha from Cobalt Digital explains the two ways people get around the unreliability of the internet: FEC and retransmission. Forward Error Correction uses some maths to transmit extra data on top of the stream which allows the receiver to correct for any packet losses. This method is standard in satellite transmission where it is always used to add robustness.
Retransmission is different in that it requires a return channel. When a receiver spots a missing packet, it asks for it to be resent. Being that it has to wait for a reply, retransmission protocols like SRT, ARQ and RIST run with a configurable buffer which needs to be big enough for at least one round trip. FEC schemes also require a buffer as it needs to wait for a number of packets before it can complete the maths required.
Ciro introduces FEC and ARQ before presenting work showing experiments he’s run on both FEC and ARQ to see the limits of their signal-correcting capabilities and latency. He finishes explaining what RIST is and its status.
Andy Rayner from Nevion looks at using SMPTE ST 2110 on a Wide Area Network (WAN).
While using ST 2110 is a much discussed topic in the studio or within a building, there are extra difficulties in putting it between buildings, cities and countries with some saying it shouldn’t even be done. Here, Andy examines how you can do it whilst acknowledging the industry still has some decisions to make.
An in-depth talk explaining DOCSIS 3.1 from SCTE by Cisco’s Ron Hranac. DOCSIS 3.1 is the latest Data-Over-Cable Service Interface Specifications.
The presentation will include information on the following:
– Why DOCSIS 3.1?
– Basic principles of Orthogonal Frequency Division Multiplexing (OFDM).
– Spectrum allocation.
– FEC performance enhancements.
– New Proactive Network Maintenance (PNM) measurements.
CableLabs released version I01 of the new specification in late October 2013. DOCSIS 3.1 introduces a new physical layer, improved Forward Error Correction (FEC) and other features for high-speed data transmission on cable networks. Scalable to 10+ Gbps in the downstream and 1+ Gbps in the upstream, DOCSIS 3.1 supports services competitive with fibre to the home, but using cable’s HFC platform. Cisco’s Ron Hranac provides an overview of DOCSIS 3.1 from a physical layer perspective.
A video on the often overlooked parts of SMPTE 2022 useful for carrying compressed as well as uncompressed video. Thomas Edwards, VP of Engineering and Development at Fox takes us through the suite in order explaining:
The difference between FEC for compressed and uncompressed video