Video: DOS Gaming Aspect Ratio – 320×200


Occasionally, talks about broadcast topics can be a little dry. Not this one which discusses aspect ratios. For those who feel they are too well versed in 16:9, 4:3 and the many other standard aspect ratios in use in the film and broadcast industries, looking at them through the lens of retro computer gaming will be a breath of fresh air. For those who are new to anything that’s not widescreen 16:9 this is a great intro to a topic of fundamental importance for anyone dealing with video.

This video is no surprise coming from YouTube channel Displaced Gamers who have previously been on The Broadcast Knowledge talking about 525-Line Analog Video and Analog Luma – A History and Explanation of Video. After a brief intro, we quickly start looking at what standard resolutions are today and their aspect ratios.

The aspect ratio of a video is a way of describing how wide it is compared to its height. This can be done by an actual ratio of width:height or displayed more mathematically as a decimal such as 1.778 in the case of 16:9 widescreen. The video discusses how old CRTs display video, their use of analogue dials that changed the width and height of the image.

In today’s world, pixels tend to be square so those encountering any pixels which aren’t square tend to work in archiving and preservation. But the reality today is that with so many second screen devices, there are all sorts of resolutions and a variety of aspect ratios. As people working in media and entertainment, we have to understand the impact on the size and shape of the video when displaying it on different screens. This video shows the impacts vividly using figurines from Doom and comparing them with the in-game graphics from Doom before then looking at aspect ratios across the SNES, Amiga, Atari ST as well as IBM DOS.

Watch now!
Speaker

Chris Kennedy Chris Kennedy
Displaced Gamers, YouTube Channel

Video: Broadcast Content Protection

With video piracy estimated to cost the US economy $29M a year and programming rights costing 100s of millions of dollars or more, there’s plenty of reason to look to technology to protect your content. There is a long history of copy protection for broadcast/linear content which is continually changing.

Graham Turner, who has worked extensively in copy protection for many years, gives us an overview of how pay TV works, a look at the different types of protection and a look back at the history to see what we can learn from the mistakes made since the late 1980s.

After explaining the many reasons different types of channels have to protect their content, Graham explains the fundamentals of content protection, encryption and decryption being central to protection discussing symmetric and asymmetric cryptography. He then discusses key length which is something we hear a lot of, but can be non-trivial to understand. After all, AES talks of 128 and 256-bit keys, whereas in other areas we hear 1024, 2048 and more. Graham shows how these relate to the different keys in symmetric and asymmetric cryptography.

Pay TV is the area of focus for this video whereby live decryption keys need to be available at the set top box (STB) in the home. For DVD copy protection, the key is already in the DVD player and revocation of the rights of that DVD player are difficult. For TV there is a path from the broadcaster to the receiver which allows for more reactive rights management. ECM, Entitlement Checking Messages and EMM, Entitlement Management Messages, are the ways in which these permissions are spread so we look at how these work.

The architecture of the STB comes in focus next as Graham explains how the decryption and describing fit together along with hardware security and software security. Naturally after the STB has decoded the video, there’s interest in making sure the delivery to the TV is also secure which is where HDMI’s HDCP comes in with HDCP 2.2 protecting UHD content. HDCP is a method of ensuring that recording devices don’t get to record protected video whereas TVs or display devices can. Fingerprinting and watermarking are two technologies which are also examined showing how they are useful, to an extent, in identification of footage though not directly useful in preventing piracy itself.

The video ends with a very interesting look at the various high profile hacks from the last 30 or so years examining what was broken and how – in particular whether the cryptography itself was broken or whether the attack succeeded due to a weak link in the chain of another part of the system.

Watch now!
Speakers

​ Graham Turner ​Graham Turner
Television Technologist,
Former Chair, IET Media

Video: Hacking ATSC 3.0

ATSC’s effort to bring IP into over-the-air broadcast has been long in the making and its deployment in South Korea along with the ITU’s inclusion of it in it’s list of recommended digital broadcast standards is a testament to it gaining acceptance. But as US broadcasters continue with test broadcasts and roll-outs in 2020, what security problems arise when IP’s included in the mix?

Acting is a great network security primer, this talk from Texas A&M’s Wayne Pecena, explains the premise and implications of creating and maintaining security in your broadcast plant. Starting by documenting the high profile attacks on broadcasters over the years, Wayne hones in on the reasons they should care from the obvious, omnipresent threat of ‘dead air’ to ‘loss of trust’ which is particularly motivating in recent years as we have seen state actors move to influence, not disrupt the normal course of life, in low-key, long-burn persistent attacks.

The talk hinges around the ‘AIC’ triad, comprising confidentiality, integrity and availability which are the three core aspects of data to protect. Integrity involves ensuring that the data are not altered either in transit or, indeed, in storage. Confidentiality revolves around ensuring that access control is maintained at all levels including physical, network-level and application live. Finally availability encompasses the fact that if the data isn’t available to the people who need it, the whole thing is pointless. Therefore supporting the availability side of the triangle includes thinking about redundancy and disaster recovery procedures.

Wayne, who is also the president of the Society of Broadcast Engineers, explains some of the attributes of a secure system which starts with security policies. These are the outer layer of any secure environment detailing how the many other layers of security will be managed and applied. Other aspects of a secure environment are appropriately layered and segmented network design, to limit what is available to anyone who does penetrate part of a system, access controls and logging.

After looking at the IETF and IEEE standards bodies, we see how the standard network models overlay neatly on the ATSC layered model with networking in the centre of them all. This leads in to a brief introduction to ‘IP’ in the sense of the the IP protocol on which are based TCP/IP and UDP/IP, between them central to most network communications around the world.

As we see how a small hole in defences can be slowly changed and enlarged allowing the attacker to move forward and create another hole in the next layer, Wayne talks about the types of security threats such malware, denial of service attacks and, of course, inside threats such as your employees themselves being complicit.

As the talk draws to a close we look at how this plays out in the real world talking through diagrams of broadcasters’ systems and how mitigations might play out on premise before talking cloud security. As the threat model in the cloud is different, Wayne explains the best practices to ensure safety and how these and the other security technologies used on the internet keep ATSC 3.0 secure including TLS secure certificate and the use of DNSSEC

The talk finishes with a look at security in the home whether that be with the myriad of consumer media consumption devices or items from the ‘internet of things’.

Watch now!
Speaker

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

Video: Things Developers Believe About Video Files (Proven Wrong by User Uploads)


For many transcoding workflows, efficiency or quality are the primary factors defining how they are created. But when ingesting user-generated videos like those uploaded to the online video platform, Vimeo, life gets difficult. Dealing with the wide variety of formats uploaded and the many edge cases in the way that otherwise normal AVC videos are delivered means throwing out any assumptions you ever had and analysing every aspect of the file.

Senior video encoding engineer, Derek Buitenhuis takes us through the many lessons he and his colleagues have learnt over the years. Don’t, he says, assume that properties don’t change between frames – sometimes they change in every single frame. Assuming that you have a single frame rate throughout the video is another ‘no no’ as there are many variable-frame rate videos.

Derek also looks at dealing with samples stamped with negative timestamps, the need for sample durations, the myriad of issues seeking through a file, the fun of having some frames that aren’t displayed and multiple-track videos.

Colour spaces, no surprise to anyone, cause handling difficulties for example if the bitstream colour properties are different to those in the container. As the talk finishes, we’re left considering old MPEG2 files that can have unavoidable banding, replicating looping MOV files, and dealing with QuickTime special effects channels that animate a fire on the screen.

Watch now!
Speakers

Derek Buitenhuis Derek Buitenhuis
Senior Video Encoding Engineer,
Vimeo