Video: Is IP Really Better than SDI?

Is SDI so bad? With the industry as a whole avidly discussing and developing IP technology, all the talk of the benefits of IP can seem like a dismissal of SDI. SDI served the broadcast industry very well for decades, so what’s suddenly so wrong with it? Of course, SDI still has a place and even some benefits over IP. Whilst IP is definitely a great technology to take the industry forward, there’s nothing wrong with using SDI in the right place.

Ed Calverley from Q3Media takes an honest look at the pros and cons of SDI. Not afraid to explain where SDI fits better than IP, this is a very valuable video for anyone who has to choose technology for a small or medium project. Whilst many large projects, nowadays, are best done in IP, Ed looks at why that is and, perhaps more importantly, what’s tricky about making it work, highlighting the differences doing the same project in SDI.

This video is the next in IET Media’s series of educational videos and follows on nicely from Gerard Phillips’ talk on Network Design for uncompressed media. Here, Ed recaps on the reasons SDI has been so successful and universally accepted in the broadcast industry as well as looking at SDI routing. This is essential to understand the differences when we move to IP in terms of benefits and compromises.

SDI is a unidirectional technology, something which makes it pleasantly simple, but at scale makes life difficult in terms of cabling. Not only is it unidirectional, but it can only really carry one video at a time. Before IP, this didn’t seem to be much of a restriction, but as densities have increased, cabling was often one limiting factor on the size of equipment – not unlike the reason 3.5mm audio jacks have started to disappear from some phones. Moreover, anyone who’s had to plan an expansion of an SDI router, adding a second one, has come across the vast complexity of doing so. Physically it can be very challenging, it will involve using tie-lines which come with a whole management overhead in and of themselves as well as taking up much valuable I/O which could have been used for new inputs and outputs, but are required for tying the routers together. Ed uses a number of animations to show how IP significantly improves media routing,

In the second part of the video, we start to look at the pros and cons of key topics including latency, routing behaviour, virtual routing, bandwidth management, UHD and PTP. With all this said, Ed concludes that IP is definitely the future for the industry, but on a project-by-project basis, we shouldn’t dismiss the advantages that do exist of SDI as it could well be the right option.

Watch now!
Speakers

Ed Ed Calverley
Trainer & Consultant
Q3Media.co.uk
Russell Trafford-Jones Moderator: Russell Trafford-Jones
Exec Member, IET Media Technical Network
Editor, The Broadcast Knowledge
Manager, Services & Support, Techex

Video: Hybrid SDI/ST 2110 Workflows

It’s no secret that SDI is still the way to go for some new installations. For all the valid interest in SMPTE’s ST 2110, the cost savings are only realised either on a large scale or in the case that a system needs continuous flexibility (such as an OB truck) or scalability in the future. Those installations which have gone IP still have some SDI lying around somewhere. Currently, there are few situations where there is an absolute ‘no SDI’ policy because there are few business cases which can afford it.

Looking at the current deployments of broadcast 2110, we have large, often public, broadcasters who are undergoing a tech refresh for a building and can’t justify such as massive investment in SDI or they are aiming to achieve specific savings such as Discovery’s Eurosport Transformation Project which is an inspirational, international project to do remote production for whole buildings. We also have OB trucks who benefit significantly from reduced cabling, higher density routing and flexibility. For a more detailed view on 2110 in trucks, watch this video from NEP. In these scenarios, there is nearly always SDI still involved. Some equipment doesn’t yet work fully in 2110, some doesn’t yet work at all and while there are IP versions of some products, the freelance community still needs to learn how to use the new products or work in the new workflows. If you have a big enough project, you’ll hit the ‘vendor not yet ready’ problem, if you have an OB-truck or similar, you are likely to have to deal with the freelance experience issue. Both are reducing, but are still real and need to be dealt with.

Kevin Salvidge from Leader joins the VSF’s Wes Simpson to share his experience of these SDI/IP mixed workflows, many of which are in OB trucks so also include mixed HDR workflows. He starts by talking about PTP and GPS discussing how timing needs to be synced between locations. He then takes a closer look at the job of the camera shaders who make sure all the cameras have the same colour, exposure etc. Kevin talks about how live production in HDR and SDR work touching on the problem of ‘immediacy’. Shaders need to swap between cameras quickly and are used to the immediate switch that SDI can provide. IP can’t offer quite the same immediacy, Kevin says that some providers have added delays into the SDI switches to match the IP switch times within the same truck. This helps set expectations and stop operators pressing two or more times to get a switch made.

Kevin finishes his talk on the topic of synchronising analogue timing signals with PTP. Kevin shows us the different tools you can use to monitor these signals such as a display of PTP timing against B&B timing, a BMCA data readout of data from the PTP grandmasters to check if the BMCA algorithm is working correctly, PTP delay time, packet inter-arrival time, path delay, traffic shaping monitoring. He then closes with a Q&A talking about the continued prevalence of SDI, what ‘eye patterns’ are in the IP world and increasing HDR roll-outs.

Watch now!
Speaker

Kevin Slavidge
European Regional Development Manager
Leader Europe Ltd.
Wes Simpson Moderator: Wes Simpson
President, Telcom Product Consulting
Owner, LearnIPVideo.com

Video: CPAC Case Study – Replacement of a CWDM System with an IP System

For a long time now, broadcasters have been using dark fibre and CWDM (Coarse Wavelength Division Multiplexing) for transmission of multiple SDI feeds to and from remote sites. As an analogue process, WDM is based on a concept called Frequency Division Multiplexing (FDM). The bandwidth of a fibre is divided into multiple channels and each channel occupies a part of the large frequency spectrum. Each channel operates at a different frequency and at a different optical wavelength. All these wavelengths (i.e., colours) of laser light are combined and de-combined using a passive prism and optical filters.

In this presentation Roy Folkman from Embrionix shows what advantages can be achieved by moving from CWDM technology to real-time media-over-IP system. The recent project for CPAC (Cable Public Affairs Channel) in Canada has been used as an example. The scope of this project was to replace an aging CWDM system connecting government buildings and CPAC Studios which could carry 8 SDI signals in each direction with a single dark fibre pair. The first idea was to use a newer CWDM system which would allow up to 18 SDI signals, but quite quickly it became apparent that an IP system could be implemented at similar cost.

As this was an SDI replacement, SMPTE ST 2022-6 was used in this project with a upgrade path to ST 2110 possible. Roy explains that, from CPAC point of view, using ST 2022-6 was a comfortable first step into real-time media-over-IP which allowed for cost reduction and simplification (no PTP generation and distribution required, re-use of existing SDI frame syncs and routing with audio breakaway capability). The benefits of using IP were: increased capacity, integrated routing (in-band control) and ease of future expansion.

A single 1RU 48-port switch on each side and a single dark fibre pair gave the system a capacity of 48 HD SDI signals in each direction. SFP gateways with small Embronix enclosures have been used to convert SDI outs of cameras to IP fibre – that also allowed to extend the distance between the cameras and the switch above SDI cabling limit of 100 meters. SFP gateway modules converting IP to SDI have been installed directly in the switches in both sites.

Roy finishes his presentation with possible future expansion of the system, such as migration to ST 2110 (firmware upgrade for SFP modules), increased capacity (by adding additional dark fibres ands switches), SDI and IP routing integration with unified control system (NMOS), remote camera control and addition of processing functions to SFP modules (Multiviewers, Up/Down/CrossConversion, Compression).

Watch now!

Download the slides.

Speaker

Roy Folkman 
VP of Sales
Embrionix

Video: Live Closed Captioning and Subtitling in SMPTE 2110 (update)

The SMPTE ST 2110-40 standard specifies the real-time, RTP transport of SMPTE ST 291-1 Ancillary Data packets. It allows creation of IP essence flows carrying the VANC data familiar to us from SDI (like AFD, closed captions or ad triggering), complementing the existing video and audio portions of the SMPTE ST 2110 suite.

This presentation, by Bill McLaughlin from EEG, is an updated tutorial on subtitling, closed captioning, and other ancillary data workflows using the ST 2110-40 standard. Topics include synchronization, merging of data from different sources and standards conversion.

Building on Bill’s previous presentation at the IP Showcase), this talk at NAB 2019 demonstrates a big increase in the number of vendors supporting ST 2110-40 standard. Previously a generic packet analyser like Wireshark with dissector was recommended for troubleshooting IP ancillary data. But now most leading multiviewer / analyser products can display captioning, subtitling and timecode from 2110-40 streams. At the recent “JT-NM Tested Program” event 29 products passed 2110-40 Reception Validation. Moreover, 27 products passed 2110-40 Transmitter Validation which mean that their output can be reconstructed into SDI video signals with appropriate timing and then decoded correctly.

Bill points out that ST 2110-40 is not really a new standard at this point, it only defines how to carry ancillary data from the traditional payloads over IP. Special care needs to be taken when different VANC data packets are concatenated in the IP domain. A lot of existing devices are simple ST 2110-40 receivers which would require a kind of VANC funnel to create a combined stream of all the relevant ancillary data, making sure that line numbers and packet types don’t conflict, especially when signals need to be converted back to SDI.

There is a new ST 2110-41 standard being developed for additional ancilary data which do not match up with ancillary data standardised in ST 291-1. Another idea discussed is to move away from SDI VANC data format and use a TTML track (Timed Text Markup Language – textual information associated with timing information) to carry ancillary information.

Watch now!

Download the slides.

Speakers

 

Bill McLaughlin Bill McLaughlin
VP of Product Development
EEG