AV1

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

Posted on by Russell Trafford-Jones


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.

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Speakers

Derek Buitenhuis Derek Buitenhuis
Senior Video Encoding Engineer,
Vimeo

Video: 2019 What did I miss? Comparing AV1, VP9, HEVC, & H.264

Posted on by Russell Trafford-Jones

The ever popular, always analytical Jan Ozers spends time here evaluating the quality of these codecs against the ever-present h.264. As the team here at The Broadcast Knowledge takes a short break, we’re recapping the most popular posts of the year. Interestingly, this post is from over a year ago but is still seeing top-10 traffic. This is no surprise since, as I said in my interview with SMPTE on the subject of codecs, everyone touches codecs in some way even if only at home. So it’s no surprise there is such an interest.

Jan takes a careful approach to explaining the penetration adn abilities of h.264 in order to see at what point we can break even and start to ebenefit from using alternative codecs. He then takes each codec in turn looking at it its pros and cons to paint a picture of the options available for those willing and able to go beyond h.264.

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Speakers

Jan Ozer Jan Ozer
Industry Analyst
Streaming Learning Center

Video: SMPTE Technical Primers

Posted on by Russell Trafford-Jones

The Broadcast Knowledge exists to help individuals up-skill whatever your starting point. Videos like this are far too rare giving an introduction to a large number of topics. For those starting out or who need to revise a topic, this really hits the mark particularly as there are many new topics.

John Mailhot takes the lead on SMPTE 2110 explaining that it’s built on separate media (essence) flows. He covers how synchronisation is maintained and also gives an overview of the many parts of the SMPTE ST 2110 suite. He talks in more detail about the audio and metadata parts of the standard suite.

Eric Gsell discusses digital archiving and the considerations which come with deciding what formats to use. He explains colour space, the CIE model and the colour spaces we use such as 709, 2100 and P3 before turning to file formats. With the advent of HDR video and displays which can show bright video, Eric takes some time to explain why this could represent a problem for visual health as we don’t fully understand how the displays and the eye interact with this type of material. He finishes off by explaining the different ways of measuring the light output of displays and their standardisation.

Yvonne Thomas talks about the cloud starting by explaining the different between platform as a service (PaaS), infrastructure as a service (IaaS) and similar cloud terms. As cloud migrations are forecast to grow significantly, Yvonne looks at the drivers behind this and the benefits that it can bring when used in the right way. Using the cloud, Yvonne shows, can be an opportunity for improving workflows and adding more feedback and iterative refinement into your products and infrastructure.

Looking at video deployments in the cloud, Yvonne introduces video codecs AV1 and VVC both, in their own way, successors to HEVC/h.265 as well as the two transport protocols SRT and RIST which exist to reliably send video with low latency over lossy networks such as the internet. To learn more about these protocols, check out this popular talk on RIST by Merrick Ackermans and this SRT Overview.

Rounding off the primer is Linda Gedemer from Source Sound VR who introduces immersive audio, measuring sound output (SPL) from speakers and looking at the interesting problem of forward speakers in cinemas. The have long been behind the screen which has meant the screens have to be perforated to let the sound through which interferes with the sound itself. Now that cinema screens are changing to be solid screens, not completely dissimilar to large outdoor video displays, the speakers are having to move but now with them out of the line of sight, how can we keep the sound in the right place for the audience?

This video is a great summary of many of the key challenges in the industry and works well for beginners and those who just need to keep up.

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Speakers

John Mailhot John Mailhot
Systems Architect for IP Convergence,
Imagine Communications
Eric Gsell Eric Gsell
Staff Engineer,
Dolby Laboratories
Linda Gedemer, PhD Linda Gedemer, PhD
Technical Director, VR Audio Evangelist
Source Sound VR
Yvonne Thomas Yvonne Thomas
Strategic Technologist
Digital TV Group

Video: Codec Comparison from TCO and Compression Efficiency Perspective

Posted on by Russell Trafford-Jones

AVC, now 16 years old, is long in the tooth but supported by billions of devices. The impetus to replace it comes from the drive to serve customers with a lower cost/base and a more capable platform. Cue the new contenders VVC and AV1 – not to mention HEVC. It’s no surprise they comptes better then AVC (also known as MPEG 4 and h.264) but do they deliver a cost efficient, legally safe codec on which to build a business?

Thierry Fautier has done the measurements and presents them in this talk. Thierry explains that the tests were done using reference code which, though unoptimised for speed, should represent the best quality possible from each codec and compared 1080p video all of which is reproduced in the IBC conference paper.

Licensing is one important topic as, by some, HEVC is seen as a failed codec not in terms of its compression but rather in the réticente by many companies to deploy it which has been due to the business risk of uncertain licensing costs and/or the expense of the known licensing costs. VVC faces the challenge of entering the market and avoiding these concerns which MPEG is determined to do.

Thierry concludes by comparing AVC against HEVC, AV1 and VVC in terms of deployment dates, deployed devices and the deployment environment. He looks at the challenge of moving large video libraries over to high-complexity codecs due to cost and time required to re-compress. The session ends with questions from the audience.
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Speaker

Thierry Fautier Thierry Fautier
President-Chair at Ultra HD Forum,
VP Video Strategy, Harmonic