NEWS

Setting the Standard: Defining Broadcast-Grade IP

by | Apr 29, 2023 | Blog Post

This is the second blog in a two-part series, the first discusses The Origins of IP, this one will explain what makes an IP feed broadcast-grade. It is important to understand that the IP transport protocol and content payload are two different entities. It is possible to have encoders and decoders that are protocol compatible and able to talk to each other but cannot deliver a content payload with the right elements for a broadcast workflow. We’ll look at the key questions to ask to ensure the right set-up for your needs.

Troubleshooting

Issues with IP transport are often created because of the back-to-front approach taken when setting up the broadcast infrastructure. Typically, content owners look at the transmission mechanism in the first instance, without considering the payload requirements or the hardware processing capabilities. This creates a problem from the outset, and one that is difficult to fix retrospectively. 

Issues arise (often during the pressures of a live event) from assumptions that the transmission mechanism and payload creation are linked. That if both the sender and the taker are using matching protocols such as SRT, then all the relevant information will be transported inside the packet. But often, technical oversights mean the feed isn’t fit for purpose.

IP Delivery – No Compromises

When it comes to establishing IP workflows, it is critical that broadcasters address requirements and problem-solve in the right order. This will ensure that IP content delivery is meeting all of the relevant broadcast requirements. High-quality, broadcast encoders can create a multi-layered payload that adheres to robust standards. With elements such as, packet timing, audio layers, subtitling, and markers for ad insertion, all preserved on arrival at the destination.

When establishing a broadcast-grade IP set-up for acquisition and contribution, the priority should always be the payload. Once the payload requirements are established, the next consideration should be where the feed must go, and only then, is it time to confirm the transmission protocols are compatible. The key things to consider are:

1.    The Payload

What is needed? Can the encoder package it and can the decoder(s) receive it without any loss or syncing issues?

  • Which codec do you need to use? It will likely be H.264 or H.265 for now but this is evolving.
  • Is it a Constant or Variable Bit Rate?
  • Does it need an open or closed GOP? What about IDR Frames?
  • Is MPEG 1 Layer II audio required? Yes, probably but some decoders can also handle AAC.
  • What bitrate do you need to create? Does it need to be 10bit 4:2:2 for a broadcast-grade video feed? If yes, then a high-bitrate to carry all of that visual data is essential – 20 to 30 megabits per second as a starting point.
  • Does it need to handle multiple audio channels? Unless you want to make yourself very unpopular with the taker, then yes this is essential.
  • Is the feed being sent to multiple takers from source?  If yes then you need to make sure that all takers can accept the source encoding format.

An encoder needs to meet the above requirements and create a robust transport feed with highly accurate packet timing, to prevent any issues.

2.    Feed Path

Next, it is time to think about where the feed needs to go. 

  • What does the path look like? 
  • Will the feed be travelling solely over an IP path? 
  • Or using a hybrid path that incorporates satellite or fibre? 
  • If it needs to be flexible and do both, a modulator is required.
  • Can all takers receive the source format?  If not then should you lower the standards to the worst case or use a cloud transcoding solution to suit those who cannot receive the best case?

3.    Transport Mechanism

And finally, now you need to choose the best way to get the feed to where it needs to go.

  • Which protocols does your encoder support?
  • Which protocols are compatible with your taker’s infrastructure? SRT? Zixi? RIST? RTMP?
  • Do their chosen decoders support the payload created?
  • If it is a mixture of protocols and you are sending to many takers then a cloud or facility service to distribute the signal may be best.
  • Can you independently monitor each delivery regardless of protocol used?

A Foundation for Success

If the payload is given the appropriate consideration, followed by the feed path, and then transport protocol, broadcasters can ensure that they make the right decisions. Setting up the right infrastructure foundation means that IP transport mechanisms can be used to their best advantage for broadcast-grade content.

You can send the content wrapped in an IP protocol, but if the encoder/decoder is not built for the job then your feed will be compromised. Like a sports car, the outside might look great, but you still need a V12 engine to get the performance you were expecting. 

Cerberus Tech has the IP video expertise needed to help you transport broadcast-grade content to global audiences. Get in touch with the team to discuss how our IP solutions, like Livelink and Network 1 can fit seamlessly into your broadcast contribution and distribution workflows.