Video: Next Generation TV Audio

Often not discussed, audio is essential to television and film so as the pixels get better, so should the sound. All aspects of audio are moving forward with more processing power at the receiver, better compression at the sender and a seismic shift in how audio is handled, even in the consumer domain. It’s fair to say that Dolby have been busy.

Larry Schindel from Linear Acoustic is here thanks to the SBE to bring us up to date on what’s normally called ‘Next Generation Audio’ (NGA). He starts from the basics looking at how audio has been traditionally delivered by channels. Stereo sound is delivered as two channels, one for each speaker. The sound engineer choosing how the audio is split between them. With the move to 5.1 and beyond, this continued with the delivery of 6, 8 or even more channels of audio. The trouble is this was always fixed at the time it went through the sound suite. Mixing sound into channels makes assumptions on the layout of your speakers. Sometimes it’s not possible to put your speakers in the ideal position and your sound suffers.

Dolby Atmos has heralded a mainstream move to object-based audio where sounds are delivered with information about their position in the soundfield as opposed to the traditional channel approach. Object-based audio leaves the downmixing to the receiver which can be set to take into account its unique room and speaker layout. It represents a change in thinking about audio, a move from thinking about the outputs to the inputs. Larry introduces Dolby Atmos and details the ways it can be delivered and highlights that it can work in a channel or object mode.

Larry then looks at where you can get media with Dolby Atmos. Cinemas are an obvious starting point, but there is a long list of streaming and pay-TV services which use it, too. Larry talks about the upcoming high-profile events which will be covered in Dolby Atmos showing that delivering this enhanced experience is something being taken seriously by broadcasters across the board.

For consumers, they still have the problem of getting the audio in the right place in their awkward, often small, rooms. Larry looks at some of the options for getting great audio in the home which include speakers which bounce sound off the ceiling and soundbars.

One of the key technologies for delivering Dolby Atmos is Dolby AC-4, the improved audio codec taking compression a step further from AC-3. We see that data rates have tumbled, for example, 5.1 surround on AC-3 would be 448Kbps, but can now be done in 144kbps with AC-4. Naturally, it supports channel and object modes and Larry explains how it can deliver a base mix with other audio elements over the top for the decoder to place allowing better customisation. This can include other languages or audio description/video description service. Importantly AC-4, like Dolby E, can be sent so that it doesn’t overlap video frames allowing it to accompany routed audio. Without this awareness of video, any time a video switch was made, the audio would become corrupted and there would be a click.

Dolby Atmos and AC-4 stand on their own and are widely applicable to much of the broadcast chain. Larry finishes this presentation mentioning that Dolby AC-4 will be the audio of choice for ATSC 3.0. We’ve covered ATSC 3.0 extensively here at The Broadcast Knowledge so if you want more detail than there is in this section of the presentation, do dig in further.

Watch now!

Speaker

Larry Schindel Larry Schindel
Senior Product Manager,
Linear Acoustic

Video: IP Fundamentals For Broadcast Seminar IV

“When networking gets real”, perhaps, could have been the title of this last of 4 talks about IP for broadcast. This session wraps up a number of topics from the classic ‘TCP Vs. UDP’ discussion to IPv6 and examines the switches and networks that make up a network as well as the architecture options. Not only that, but we also look at VPNs and firewalls finishing by discussing some aspects of network security. When viewed with the previous three talks, this discusses many of the nuances from the topics already covered bringing in the relevance of ‘real world’ situations.

Wayne Pecena, President of SBE, starts by discussing subnets and collision domains. The issue with any NIC (Network Interface Controller) is that it’s not to know when someone else is talking on the wire (i.e. when another NIC is sending a message by changing the voltage of the wire). It’s important that NICs detect when other NICs are sending messages and seek to avoid sending while this is happening. If this does’t work out well, then two messages on the same wire are seen as a ‘collision’. It’s no surprise that collisions are to be avoided which is the starting point of Wayne’s discussion.

Moving from Layer 2 to Layer 4, Wayne pits TCP against UDP looking at the pros and cons of each protocol. Whilst this is no secret, as part of the previous talks this is just what’s needed to round the topic off ahead of talking about network architecture.

“Building and Securing a Segmented IP Network Infrastructure” is the title of the next talk which starts to deal with real-world problems when an engineer gets back from a training session and starts to actually specify a network herself. How should the routers and switches be interconnected to deliver the functionality required by the business and, as we shall see, which routers/switches are actually needed? Wayne discusses some of the considerations of purchasing switches (layer 2) and routers (layer 3 & 2) including the differing terms used by HP and Cisco before talking about how to assign IP addresses, also called an IP space. Wayne takes us through IP addressing plans, examples of what they would look like in excel along with a lot of the real-world thinking behind it.

Security is next on the list, not just in terms of ‘cybersecurity’ in the general sense but in terms of best practice, firewalls and VPNs. Wayne takes a good segment of time out to discus the different aspects of firewalls – how they work, ACLs (Access-control Lists), and port security amongst other topics before doing the same for VPNs (Virtual Private Networks) before making the point that a VPN and a firewall are not the same. A VPN allows you to extend a network out from a building to be in another – the typical example being from your work’s address into your home. Whilst a VPN is secured so that only certain people can extend the network, a firewall more generally acts to prevent anything coming into a network.

As an addendum to this talk, Wayne explains IPV4 depletion and how IPv6 addressing works. In practice, for broadcasters deploying within their company in the year 2020, IPv6 is unlikely to be a topic needed. However, for people who are distributing to homes and working closer with CDNs and ISPs, there is a chance that this information is more relevant on a day-to-day basis. Whilst IP address depletion is a real thing, since every company has a 10.x.x.x address space to play with, most companies use internal equipment with an IPv4 address plan.
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Speaker

Wayne Pecena Wayne Pecena
Director of Engineering, KAMU TV/FM at Texas A&M University
President, Society of Broadcast Engineers AKA SBE

Video: Recent Experiences with ATSC 3.0 from Seoul to Phoenix

This talk is part of a series of talks on ATSC 3.0 we’re featuring here on The Broadcast Knowledge. ATSC 3.0 is a big change in terrestrial television transmission because even over the air, the signal is IP.

In this talk, Joe Seccia from GatesAir, a company famed for its transmission systems, talks us through where the US (and Seoul) is on its way to deploying this technology.

With major US broadcasters having pledged to be on air with ATSC 3.0 by the end of 2020, trials are turning in to deployments and this is a report back on what’s been going on.

Joe covers the history of previous tests and trials before taking us through the architecture of a typical system. After explaining the significance of the move to IP, Joe also covers other improvements such as using OFDM modulation and thus being able to use a single frequency network (SFN). This combination of technologies improves reception and coverage over the 8VSB transmissions which went before it.

We also hear about the difference between home and broadcast gateways in the system as well as the Early Alert System Augmentation features which allow a broadcaster to ‘wake up’ TVs and other devices when disasters strike or are predicted.

Watch now!

Speakers

Joe Seccia Joe Seccia
Manager, TV Transmission Market and Product Development Strategy,
GatesAir