Measuring video quality automatically is invaluable and, for many uses, essential. But as video evolves with higher frame rates, HDR, a wider colour gamut (WCG) and higher resolutions, we need to make sure the automatic evaluations evolve too. Called ‘Objective Metrics’, these computer-based assessments go by the name of PSNR, DMOS, VMAF and others. One use for these metrics is to automatically analyse an encoded video to determine if it looks good enough and should be re-encoded. This allows for the bitrate to be optimised for quality. Rafael Sotelo, from the Universidad de Montevideo, explains how his university helped work on an update to Predicted MOS to do just this.
MOS is the Mean Opinion Score and is a result derived from a group of people watching some content in a controlled environment. They vote to say how they feel about the content and the data, when combined gives an indication of the quality of the video. The trick is to enable a computer to predict what people will say. Rafael explains how this is done looking at some of the maths behind the predicted score.
In order to test any ‘upgrades’ to the objective metric, you need to test it against people’s actual score. So Rafael explains how he set up his viewing environments in both Uruguay and Italy to be compliant with BT.500. BT.500 is a standard which explains how a room should be in order to have viewing conditions which maximise the ability of the viewers to appreciate the pros and cons of the content. For instance, it explains how dim the room should be, how reflective the screens and how they should be calibrated. The guidelines don’t apply to HDR, 4K etc. so the team devised an extension to the standard in order to carryout the testing. This is called ‘subjective testing’.
With all of this work done, Rafael shows us the benefits of using this extended metric and the results achieved.
With all the talk of IP, you’d be wrong to think SDI is dead. 12G for 4K is alive and well in many places, so there’s plenty of appetite to understand how it works and how to diagnose problems.
In this double-header, Steve Holmes from Tektronix takes us through the ins and outs of HDR and also SDI for HDR at the SMPTE SF section.
Steve starts with his eye on the SMPTE standards for UHD SDI video looking at video resolutions and seeing that a UHD picture can be made up of 4 HD pictures which gives rise to two well known formats ‘Quad split’ and ‘2SI’ (2 Sample Interleave).
Colour is the next focus and a discussion on the different colour spaces that UHD is delivered with (spoiler: they’re all in use), what these look like on the vector scope and look at the different primaries. Finishing up with a roundup and a look at interlink timing, there’s a short break before hitting the next topic…HDR
High Dynamic Range is an important technology which is still gaining adoption and is often provided in 4K programmes. Steve defines the two places HDR is important; in the acquisition and the display of the video then provides a handy lookup table of terms such as HDR, WCG, PQ, HDR10, DMCVT and more.
Steve gives us a primer on what HDR is in terms of brightness ‘NITS’, how these relate to real life and how we talk about it with respect to the displays. We then look at HDR on the waveform monitor and look at features of waveform monitors which allow engineers to visualise and check HDR such as false colour.
The topic of gamma, EOTFs and colour spaces comes up next and is well explained building on what came earlier. Before the final demo and Q&A, Steve talks about different ways to grade pictures when working in HDR.
This on-demand webinar brings together Nighel Walley from Decipher, Paul Gagnon from IHS Markt, to talk all things CES with David Mercer from Strategy Analytics and Justin Lebbon from Mediatel events.
CES is used as a barometer of things to come and things that are on the way out and has a strong link into parts of the broadcast industry. At the end of the day, people change and technology changes; whatever your company, if you don’t change to suit, then you’ll be out of business.
So what’s hot and what’s off the boil this year? Find out as they cover 5G, 4K, AI, Screen tech and much more.
Held a couple of months before SMPTE 2110 was ratified at IBC, this panel discussion with Riedel, Evertz, EVS and Grass Valley looks at the state of SDI and IP: Which technologies are relevant now and which will win in the long run?
The conversation covers these topics and more:
12G Vs 3G SDI
Versions of UHD SDI
When should a vendor implement IP?
Will the future include compression?
How do you handle variable latencies with compression?
With the first all-IP and 12G-SDI OB trucks beginning to hit the road, and an increasing number of broadcast centres implementing comprehensive IP-based or hybrid infrastructures, this discussion will focus on the issue of connectivity and whether it is advantageous to use SDI or IP infrastructures – or indeed hybrid approaches utilising both. This panel discussion discussed the imperatives behind this dramatic technological change, the challenges that it presents, and the probable roadmap for the next few years. There will also be analysis of current industry initiatives such as AIMS and the ways in which these can help smooth the transition.
This Panel was part of the Broadcast Innovation Day hold by Broadcast Solutions GmbH.
Laurent Petit, VP Products, EVS
Simon Reed, Managing Director, Evertz UK
Thomas Riedel, CEO, RIEDEL Communications GmbH & Co. KG
Phil Myers, Former IP Product Manager, Grass Valley (formerly Snell Advanced Media (SAM))
Moderation: David Davies, Managing Editor, SVG Europe
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