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The State of #HDR in Broadcast and OTT – CES 2016 update

By Yoeri Geutskens

This article was first published in December 2015, but has been updated post-CES 2016 (corrections on Dolby Vision, UHD Alliance's "Ultra HD Premium" specification and the merging of Technicolor and Philips HDR technologies).

A lot has been written about HDR video lately, and from all of this perhaps only one thing becomes truly clear – that there appear to be various standards to choose from. What’s going on in this area in terms of technologies and standards? Before looking into that, let’s take a step back and look at what HDR video is and what’s the benefit of it.

Since 2013, Ultra HD or UHD has come up as a major new consumer TV development. UHD, often also referred to as ‘4K’, has a resolution of 3,840 x 2,160 – twice the horizontal and twice the vertical resolution of 1080p HDTV, so four times the pixels. UHD has been pushed above all by TV manufacturers looking for new ways to entice consumers to buy new TV sets. To appreciate the increased resolution of UHD, one needs to have a larger screen or a smaller viewing distance but it serves a trend towards ever larger TV sizes.

While sales of UHD TV sets are taking off quite prosperously, the rest of the value chain isn’t following quite as fast. Many involved feel the increased spatial resolution alone is not enough to justify the required investments in production equipment. Several other technologies promising further enhanced video are around the corner however. They are:

  • High Dynamic Range or HDR
  • Deep Color Resolution: 10 or 12 bits per subpixel
  • Wide Color Gamut or WCG
  • High Frame Rate or HFR: 100 or 120 frames per second (fps)

As for audio, a transition from conventional (matrixed or discrete) surround sound to object-based audio is envisaged for the next generation of TV.

Of these technologies, the first three are best attainable in the short term. They are also interrelated.

So what does HDR do? Although it’s using rather different techniques, HDR video is often likened to HDR photography as their aims are similar: to capture and reproduce scenes with a greater dynamic range than traditional technology can, in order to offer a more true-to-life experience. With HDR, more detail is visible in images that would otherwise look either overexposed, showing too little detail in bright areas, or underexposed, showing too little detail in dark areas.

HDR video is typically combined with a feature called Wide Color Gamut or WCG. Traditional HDTVs use a color space referred to as Rec.709, which was defined for the first generations of HDTVs which used CRT displays. Current flat panel display technologies like LCD and OLED can produce a far wider range of colors and greater luminance, measured in ‘nits’. A nit is a unit for brightness, equal to candela per square meter (cd/m2). To accommodate this greater color gamut, Rec.2020 color space was defined. No commercial display can fully cover this new color space but it provides room for growth. The current state of the art of color gamut for displays in the market is a color space called DCI-P3 which is smaller than Rec.2020 but substantially larger than Rec.709.

To avoid color banding issues that could otherwise occur with this greater color gamut, HDR/WCG video typically uses a greater sampling resolution of 10 or 12 bits per subpixel (R, G and B) instead of the conventional 8 bits, so 30 or 36 bits per pixel rather than 24.

Sony-Color-space

Color/luminance volume: BT.2020 (10,000 nits) versus BT.709 (100 nits); Yxy
Image credit: Sony

The problem with HDR isn’t so much on the capture side nor on the rendering side – current professional digital cameras can handle a greater dynamic range and current displays can produce a greater contrast than the content chain in between can handle. It’s the standards for encoding, storage, transmission and everything else that needs to happen in between that are too constrained to support HDR.

So what is being done about this? A lot, in fact. Let’s look at the technologies first. A handful of organizations have proposed technologies for describing HDR signals for capture, storage, transmission and reproduction. They are Dolby, SMPTE, Technicolor, Philips, and BBC together with NHK. Around the time of CES 2016, Technicolor and Philips have announced they are going to merge their HDR technologies.

Dolby’s HDR technology is branded Dolby Vision. One of the key elements of Dolby Vision is the Perceptual Quantizer EOTF which has been standardized by SMPTE as ST 2084 (see box: SMPTE HDR Standards) and mandated by the Blu-ray Disc Association for the new Ultra HD Blu-ray format. The SMPTE ST 2084 format can actually contain more picture information than TVs today can display but because the information is there as manufacturers build better TVs the content has the potential to look better as the new, improved display technologies come to market. Dolby Vision and HDR10 use the same SMPTE 2084 standard making it easy for studios and content producers to master once and deliver to either HDR10 or, with the addition of dynamic metadata, Dolby Vision. The dynamic metadata is not an absolute necessity, but using it guarantees the best results when played back on a Dolby Vision-enabled TV. HDR10 uses static metadata which ensures it will still look good – far better than Standard Dynamic Range (SDR). Even using no metadata at all, SMPTE 2084 can work at an acceptable level just as other proposed EOTFs without metadata do.

For live broadcast Dolby supports both single and dual layer 10-bit distribution methods and has come up with a single workflow that can simultaneously deliver an HDR signal to the latest generation and future TVs and a derived SDR signal to support all legacy TVs. The signal can be encoded in HEVC or AVC. Not requiring dual workflows will be very appealing to all involved in content production and the system is flexible to let the broadcaster choose where to derive the SDR signal.  If it’s done at the head-end they can choose to simply simulcast it as another channel or convert the signal to dual-layer single stream signal at the distribution encoder for transmission.  Additionally the HDR-to-SDR conversion can be built into set-top boxes for maximum flexibility without compromising the SDR or HDR signals. Moreover, the SDR distribution signal that’s derived from the HDR original using Dolby’s content mapping unit (CMU) is significantly better in terms of detail and color than one that’s captured natively in SDR, as Dolby demonstrated side by side at IBC 2015. The metadata is only produced and multiplexed into the stream at the point of transmission, just before or in the final encoder – not in the baseband workflow. Dolby uses 12-bit color depth for cinematic Dolby Vision content to avoid any noticeable banding but the format is actually agnostic to different color depths and works with 10-bit video as well. In fact, Dolby recommends 10-bit color depth for broadcast.

High-level overview of Dolby Vision dual-layer transmission for OTT VOD

High-level overview of Dolby Vision dual-layer transmission for OTT VOD;
other schematics apply for OTT live, broadcast, etc. 
Image credit: Dolby Labs Dolby Vision white paper

Technicolor has developed two HDR technologies. The first takes a 10-bit HDR video signal from a camera and delivers a video signal that is compatible with SDR as well as HDR displays. The extra information that is needed for the HDR rendering is encoded in such a way that it builds on top of the 8-bit SDR signal but SDR devices simply ignore the extra data.

Technicolor

Image credit: Technicolor

The second technology is called Intelligent Tone Management and offers a method to ‘upscale’ SDR material to HDR, using the extra dynamic range that current-day capture devices can provide but traditional encoding cannot handle, and providing enhanced color grading tools to colorists. While it remains to be seen how effective and acceptable the results are going to be, this technique has the potential to greatly expand the amount of available HDR content.

Having a single signal that delivers SDR to legacy TV sets (HD or UHD) and HDR to the new crop of TVs is also the objective of what BBC’s R&D department and Japan’s public broadcaster NHK are working on together.  It’s called Hybrid Log Gamma or HLG. HLG’s premise is an attractive one: a single video signal that renders SDR on legacy displays but HDR on displays that can handle this. HLG, BBC and NHK say, is compatible with existing 10-bit production workflows and can be distributed using a single HEVC Main 10 Profile bitstream.

Depending on whom you ask HLG is the best thing since sliced bread or a clever compromise that accommodates SDR as well as HDR displays but gives suboptimal results and looks great on neither. The Hybrid Log Gamma name refers to the fact that the OETF is a hybrid that applies a conventional gamma curve for low-light signals and a logarithmic curve for the high tones.

HLG

Hybrid Log Gamma and SDR OETFs; image credit: T. Borer and A. Cotton, BBC R&D

Transfer functions:

  • OETF: function that maps scene luminance to digital code value; used in HDR camera;
  • EOTF: function that maps digital code value to displayed luminance; used in HDR display;
  • OOTF: function that maps scene luminance to displayed luminance; a function of the OETF and EOTF in a chain. Because of the non-linear nature of both OETF and EOTF, the chain’s OOTF also has a non-linear character.

 BBC_WorkFlow

Image credit: T. Borer and A. Cotton, BBC R&D

The EOTF for Mastering Reference Displays, conceived by Dolby and standardized by SMPTE as ST 2084 is ´display-referred'.  With this approach, the OOTF is part of the OETF, requiring implicit or explicit metadata.

Hybrid Log Gamma (HLG), proposed by BBC and NHK, is a 'scene-referred' system which means the OOTF is part of the EOTF. HLG does not require mastering metadata so the signal is display-independent and can be displayed unprocessed on an SDR screen.

The reasoning is simple: bandwidth is scarce, especially for terrestrial broadcasting but also for satellite and even cable, so transmitting the signal twice in parallel, in SDR and HDR, is not an attractive option. In fact, most broadcasters are far more interested in adding HDR to 1080p HD channels than in launching UHD channels, for exactly the same reason. Adding HDR is estimated to consume up to 20% extra bandwidth at most, whereas a UHD channel gobbles up the bandwidth of four HD channels. It’s probably no coincidence HLG technology has been developed by two broadcast companies that have historically invested a lot in R&D. Note however that the claimed backwards compatibility of HLG with SDR displays only applies to displays working with Rec.2020 color space, i.e. Wide Color Gamut. This more or less makes its main benefit worthless.

ARIB, the Japanese organization that’s the equivalent of DVB in Europe and ATSC in North America, has standardized upon HLG for UHD HDR broadcasts.

The DVB Project meanwhile has recently announced that UHD-I phase 2 will actually include a profile that adds HDR to 1080p HD video – a move advocated by Ericsson  and supported by many broadcasters. Don’t expect CE manufacturers to start producing HDTVs with HDR however. Such innovations are likely to end up only in the UHD TV category, where the growth is and any innovation outside of cost reductions takes place.

This means consumers will need a HDR UHD TV to watch HD broadcasts with HDR. Owners of such TV sets will be confronted with a mixture of qualities – plain HD, HD with HDR, plain UHD and UHD with HDR (and WCG), much in the same way HDTV owners may watch a mix of SD and HD television, only with more variations.

The SMPTE is one of the foremost standardization bodies active in developing official standards for the proposed HDR technologies. See box ‘SMPTE HDR standards’.

SMPTE HDR Standards

ST 2084:2014 - High Dynamic Range EOTF of Mastering Reference Displays

  • defines 'display referred' EOTF curve with absolute luminance values based on human visual model
  • called Perceptual Quantizer (PQ)

ST 2086:2014 - Mastering Display Color Volume Metadata supporting High Luminance and Wide Color Gamut images

  • specifies mastering display primaries, white point and min/max luminance

Draft ST 2094:201x - Content-dependent Metadata for Color Volume Transformation of High-Luminance and Wide Color Gamut images

  • specifies dynamic metadata used in the color volume transformation of source content mastered with HDR and/or WCG imagery, when such content is rendered for presentation on a display having a smaller color volume

One other such body is the Blu-ray Disc Association (BDA). Although physical media have been losing some popularity with consumers lately, few people are blessed with a fast enough broadband connection to be able to handle proper Ultra HD video streaming, with or without HDR. Netflix requires at least 15 Mbps sustained average bitrate for UHD watching but recommends at least 25 Mbps. The new Ultra HD Blu-ray standard meanwhile offers up to 128 Mpbs peak bit rate. Of course one can compress Ultra HD signals but the resulting quality loss would defy the entire purpose of Ultra High Definition.

Ultra HD Blu-ray may be somewhat late to the market, with some SVOD streaming services having beat them to it, but the BDA deserves praise for not rushing the new standard to launch without HDR support. Had they done that, the format may very well have been declared dead on arrival. The complication, of course, was that there was no single agreed-upon standard for HDR yet. The BDA has settled on the HDR10 Media Profile (see box) as mandatory for players and discs with Dolby Vision and Philips’ HDR format as optional for players as well as discs.

HDR10 Media Profile

  • EOTF: SMPTE ST 2084
  • Color sub-sampling: 4:2:0 (for compressed video sources)
  • Bit depth: 10 bit
  • Color primaries: ITU-R BT.2020
  • Metadata: SMPTE ST 2086, MaxFall (Maximum Frame Average Light Level), MaxCLL (Maximum Content Light Level)

Referenced by:

  1. Ultra HD Blu-ray spec (Blu-Ray Disc Association)
  2. HDR-compatible display spec (CTA; former CEA)

UHD Alliance ‘Ultra HD Premium’ definition Display Content Distribution
Image resolution 3840×2160 3840×2160 3840×2160
Color Bit Depth 10-bit signal Minimum 10-bit signal depth Minimum 10-bit signal depth
Color Palette Signal input: BT.2020 color representation

Display reproduction: More than 90% of P3 color space

BT.2020 color representation BT.2020 color representation
High Dynamic Range SMPTE ST 2084 EOTF

A combination of peak brightness and black level either:

More than 1000 nits peak brightness and less than 0.05 nits black level
or

More than 540 nits peak brightness and less than 0.0005 nits black level

SMPTE ST 2084 EOTF

Mastering displays recommended to exceed 1000 nits in brightness, less than 0.03 black level, minimum of DCI-P3 color space

SMPTE ST 2084 EOTF

The UHD Alliance mostly revolves around Hollywood movie studios and is focused on content creation and playback, guidelines for CE devices, branding and consumer experience). At CES 2016, the UHDA has announced a set of norms for displays, content end ‘distribution’ to deliver UHD with HDR, and an associated logo program. The norm is called ‘Ultra HD Premium’ (see box). Is it a standard? Arguably, yes. Does it put an end to any potential confusion over different HDR technologies? Not quite – while the new norm guarantees a certain level of dynamic range it does not specify any particular HDR technology, so all options are still open. 

The Ultra HD Forum meanwhile focuses on the end-to-end content delivery chain including production workflow and distribution infrastructure.

In broadcasting we’ve got ATSC in North America defining how UHD and HDR should be broadcast over the air with the upcoming ATSC 3.0 standard (also used in South Korea) and transmitted via cable. Here, the SCTE comes into play as well. Japan has the ARIB (see above) and for most of the rest of the world, including Europe, there’s the DVB Project, part of the EBU, specifying how UHD and HDR should fit into the DVB standards that govern terrestrial, satellite and cable distribution.

In recent news, the European Telecommunications Standards Institute (ETSI) has launched a new Industry Specification Group (ISG) “to work on a standardized solution to define a scalable and flexible decoding system for consumer electronics devices from UltraHD TVs to smartphones” which will look at UHD, HDR and WCG. Founding members include telcos BT and Telefónica. The former already operates a UHD IPTV service; the latter is about to launch one.

Then there are CTA (Consumer Technology Association, formerly known as CEA) in the US and DigitalEurope dealing with guidelines and certification programs for consumer products. What specifications does a product have to support to qualify for ‘Ultra HD’ branding? Both have formulated answers to that question. It has not been a coordinated effort but fortunately they turn out to almost agree on the specs. Unity on a logo was not as feasible, sadly. The UHD Alliance has just announced they’ve settled on a definition of Ultra HD they’ll announce at CES, January 4th, 2016. One can only hope this will not lead to yet more confusion (and more logos) but I’m not optimistic.

By now, the CTA has also issued guidelines for HDR. DigitalEurope hasn’t yet. It’d be great for consumers, retailers and manufacturers alike if the two organizations could agree on a definition as well as a logo this time.

Ultra HD display definition CTA definition DigitalEurope definition
Resolution At least 3840x2160 At least 3840x2160
Aspect ratio 16:9 or wider 16:9
Frame rate Supporting 24p, 30p and 60p 24p, 25p, 30p, 50p, 60p
Chroma subsampling Not specified 4:2:0 for 50p, 60p

4:2:2 for 24p,25p, 30p

Color bit depth Minimum 8-bit Minimum 8-bit
Colorimetry BT.709 color space; may support wider colorimetry standards Minimum BT.709
Upconversion Capable of upscaling HD to UHD Not specified
Digital input One or more HDMI inputs supporting HDCP 2.2 or equivalent content protection. HDMI with HDCP 2.2
Audio Not specified PCM 2.0 Stereo
Logo  CTA Logo UHD  DigitalEur Logo UHD

CTA definition of HDR-compatible:

A TV, monitor or projector may be referred to as a HDR Compatible Display if it meets the following minimum attributes:

  1. Includes at least one interface that supports HDR signaling as defined in CEA-861-F, as extended by CEA-861.3.
  2. Receives and processes static HDR metadata compliant with CEA-861.3 for uncompressed video.
  3. Receives and processes HDR10 Media Profile* from IP, HDMI or other video delivery sources. Additionally, other media profiles may be supported.
  4. Applies an appropriate Electro-Optical Transfer Function (EOTF), before rendering the image.

CEA-861.3 references SMPTE ST 2084 and ST 2086.

What are consumers, broadcasters, TV manufacturers, technology developers and standardization bodies to do right now?

I wouldn’t want to hold any consumer back but I couldn’t blame them if they decided to postpone purchasing a new TV a little longer until standards for HDR have been nailed. Similarly, for broadcasters and production companies it only seems prudent to postpone making big investments in HDR production equipment and workflows.

For all parties involved in technology development and standardization, my advice would be as follows. It’s inevitable we’re going to see a mixture of TV sets with varying capabilities in the market – SDR HDTVs, SDR UHD TVs and HDR UHD TVs, and that’s not even taking into consideration near-future extensions like HFR.

Simply ignoring some of these segments would be a very unwise choice: cutting off SDR UHD TVs from a steady flow of UHD content for instance would alienate the early adopters who bought into UHD TV already. The CE industry needs to cherish these consumers. It’s bad enough that those Brits who bought a UHD TV in 2014 cannot enjoy BT Sport’s Ultra HD service today because the associated set-top box requires HDCP 2.2 which their TV doesn’t support.

It is not realistic to cater to each of these segments with separate channels either. Even if the workflows can be combined, no broadcaster wants to spend the bandwidth to transmit the same channel in SDR HD and HDR HD, plus potentially SDR UHD and HDR UHD.

Having separate channels for HD and UHD is inevitable but for HDR to succeed it’s essential for everyone in the production and delivery chain that the HDR signal be an extension to the broadcast SDR signal and the SDR signal be compatible with legacy Rec.709 TV sets.

Innovations like Ultra HD resolution, High Dynamic Range, Wide Color Gamut and High Frame Rate will not come all at once with a big bang but (apart from HDR and WCG which go together) one at a time, leading to a fragmented installed base. This is why compatibility and ‘graceful degradation’ are so important: it’s impossible to cater to all segments individually.

What is needed now is alignment and clarity in this apparent chaos of SDOs (Standards Defining Organizations). Let’s group them along the value chain:

Domain Production Compression Broadcast Telecom Media/ Streaming CE
SDO SMPTE, ITU-R MPEG , VCEG ATSC, SCTE, EBU/DVB, ARIB, SARFT ETSI BDA, DECE (UV), MovieLabs CTA, DigitalEurope, JEITA

Within each segment, the SDOs need to align because having different standards for the same thing is counterproductive. It may be fine to have different standards applied, for instance if broadcasting uses a different HDR format than packaged media; after all, they have differing requirements. Along the chain, HDR standards do not need to be identical but they have to be compatible. Hopefully organizations like the Ultra HD Forum can facilitate and coordinate this between the segments of the chain.

If the various standardization organizations can figure out what HDR flavor to use in which case and agree on this, the future is looking very bright indeed.

Further reading:

Yoeri Geutskens has worked in consumer electronics for more than 15 years. He writes about high-resolution audio and video. You can follow him on Ultra HD and 4K on twitter @UHD4k.

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User experience gain must trump resource consumption for UHD success

This opinion blog is about 3 things that could derail UHD if User Experience lets them.

Ok so you can already tell that I’m biased. I believe in UHD and its five components that will change user experience:

  1. Higher resolution (4K)
  2. Higher Dynamic Range (ability to see details in both brighter whites and darker blacks simultaneously)
  3. Better colour (more colours, closer to human perception)
  4. Better sound (more channels than speakers, object based surround sound)
  5. Higher refresh rate (especially for action which can otherwise look choppy at very high resolution without higher refresh rates)

My crystal ball hasn’t confirmed that this is the order in which these components will arrive, or to what extent it’ll be a big bang approach, or even if some components might get left by the wayside. I’ll delve into that in another blog. In the last 15 years or so, I’ve witnessed HD succeed and I have written several times about why I believe UHD’s time is now (recently here or here in early 2014 for example). I have nothing to sell and no vested interest in UHD, I’m simply driven by my geeky fascination with the promise of a great new experience brought to TV and IP technologies that I’ve been working with for so long.

But just in case I am wrong, here are 3 things that that some of us fret about and still could prevent UHD success.

Thing Description Issue Why it won’t stop UHD
Fragmentation Vendors pulling in different directions Device & content incompatibility Industry bodies like the Ultra HD Forum or the UHD Alliance
Energy Extra brightness, more pixels and more images consume more power Regulation, consumer reluctance, UHD perceived as not Politically Correct Technology progress has often consumed more power (e.g. HD vs SD). Better efficiency means extra power required is less than extra user experience delivered. CPE power issue is more in standby mode than peak consumption. Need not consume much more power with HD-only signal.
Bandwidth UHD can require over 4 times HD bandwidth / file size. Channel and content distribution issues. Monthly data caps will be an issue for OTT households. Networks grow in quantum leaps, UHD will help spur the next one. All-fibre connections and future 5G networks will provide more bandwidth than UHD can consume. A new generation of low-orbit satellites is also on its way.

The driving force providing the impetus to overcome challenges such as those mentioned above is User Experience. This is the part of the equation I have to rely on gut feeling or faith for. My premise is that UHD ushers in a great new User Experience with a sensation of realism and immersion.

If it actually turned out that UHD didn’t bring that “wow” effect so many of us in the industry believe in, then any one of the above “things” could alone derail UHD from becoming a market success and we’ll have to find another game changer in the TV industry.  My experience so far suggests that UHD will be that game change but also that there are still niggles that need ironing out.

As it happens I’ve been watching quite a lot of 4K TV via Amazon and Netflix in the last few months. Landscapes and close-ups are all pretty amazing, but I do have a nagging worry over some indoor scenes, which despite being shot by top-of the range pros (e.g. Amazon’s Transparent, or Breaking Bad, …) leave a strange feeling that something isn’t quite right in 4K resolution. It occurs when there is some mild camera movement yet when most of the scene is in focus. I get this counterintuitive sensation that there is something maybe amateurish in the composition. This could be due to the shooting not having been properly thought out by the director and cameraman for 4K TV playback, or maybe it’s just me not yet being used to processing so much data on screen. If either of these is true, which I suspect is the case, the issue will quickly disappear. But this highlights my only real concern over UHD’s success: will it be consistently “wow” enough to overcome resistances like the three issues stated above? If so I have no doubts that vendors, content providers and operators, as personified in the Ultra HD Forum, will be insure that the whole UHD movement is not derailed by relatively minor teething troubles.

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“HaLow” sets stage for multi-channel Wi-Fi

The Wi-Fi Alliance’s announcement of the low power version IEEE 802.11ah, dubbed “HaLow”, was dismissed by some analysts as being too late to make a significant impact in the fast growing Internet of Things (sector). That view is wrong and seriously discounts the power and momentum behind Wi-Fi, to the extent that HaLow has already received extensive coverage in the popular as well as technical press. It is already far closer to being a household name than other longstanding contenders as wireless protocols for IoT devices such as Zigbee and Zwave.

It is true that certification of HaLow compliant products will not begin until 2018, but with IoT surging forward on a number of fronts including the smart car, digital home and eHealth, SoC vendors such as Qualcomm are likely to bring out silicon before that. There are good reasons for expecting HaLow to succeed, some relating to its own specifications and others more to do with the overall evolution of Wi-Fi as a whole.

Another factor is the current fragmentation among existing contenders, with a number of other protocols vying alongside Zigbee and Zwave. This may seem to be a reason for not needing yet another protocol but actually means none of the existing ones have gained enough traction to repel a higher profile invader.

More to the point though HaLow has some key benefits over the others, one being its affinity to IP and Internet through being part of Wi-Fi. Zigbee has responded by collaborating with another wireless protocol developer Thread to incorporate IP connectivity. But HaLow has other advantages, including greater range and ability to operate in challenging RF environments. There is already a sense in which the others are having to play catch up even though they have been around for much longer.

It is true that Bluetooth now has its low energy version to overcome the very limited range of the main protocol, but even this is struggling to demonstrate adequate performance over larger commercial sites. The Wi-Fi Alliance claims that HaLow is highly robust and can cope with most real sites from large homes having thick walls containing metal, to concrete warehouse complexes.

 

The big picture is that Wi-Fi is looking increasingly like a multi-channel protocol operating at a range of frequencies to suit differing use cases. To date we have two variants, 2.4 GHz and 5 GHz, which tend to get used almost interchangeably, with the latter doubling up to provide capacity when the former is congested. In future though there will be four channels, still interchangeable but tending to be dedicated to different applications, combining to yield a single coherent standard that will cover all the basses and perhaps vie with LTE outdoors for connecting various embedded IoT and M2M devices.

HaLow comes in at around 900 MHz, which means it has less bandwidth but greater coverage than the higher frequency Wi-Fi bands and has been optimized to cope well with interference both from other radio sources and physical objects. Then we have the very high frequency 802.11ad or WiGig standard coming along at 60 GHz enabling theoretical bit rates of 5 Gbps or more, spearheaded by Qualcomm, Intel and Samsung. WiGig is a further trade-off between speed and coverage and it will most likely be confined to in-room distribution of decoded ultra HD video perhaps from a gateway or set top to a big screen TV or home cinema.

Then the 5 GHz version might serve premium video to other devices around the home, while 2.4 GHz delivers general Internet access. That would leave HaLow to take care of some wearables, sensors and other low power devices that need coverage but only modest bit rates. As it happens HaLow will outperform all the other contenders for capacity except Bluetooth, with which it will be on much of a par.

 

HaLow will be embraced by key vendors in the smart home and IoT arena, such as Paris based SoftAtHome, which already supports the other key wireless protocols in its software platform through its association with relevant hardware and SoC vendors. SoftAtHome can insulate broadband operators from underlying protocols so that they do not have to be dedicated followers of the wireless wars.

AirTies is another vendor with a keen interest as one of the leading providers of Wi-Fi technology for the home, already aiming to deliver the levels of coverage and availability promised by HaLow in the higher 2.4 GHz and 5 GHz bands. It does this by creating a robust mesh from multiple Access Points (APs), to make Wi-Fi work more like a wired point to point network while retaining all the flexibility of wireless.

 

All these trends are pointing towards Wi-Fi becoming a complete quad-channel wireless offering enabling operators to be one stop shops for the digital home of the future, as well as being able to address many IoT requirements outside it.

At the same time it is worth bearing in mind that the IoT and its relative M2M is a very large canvas, extending to remote outdoor locations, some of which are more far challenging for RF signals than almost any home. In any case while HaLow may well see off all-comers indoors, it will only be a contender out doors in areas close to fixed broadband networks. That is why there is so much interest in Heterogeneous Networks (HetNets) combining Wi-Fi with LTE and also why there are several other emerging wireless protocols for longer distance IoT communications.

One of these others is Long Range Wide Area Network (LoRaWAN), a low power wireless networking protocol announced in March 2015, designed for secure two way communication between low-cost battery-powered embedded devices. Like HaLow it runs at sub-GHz frequencies, but in bands reserved for scientific and industrial applications, optimized for penetrating large structures and subsurface infrastructures within a range of 2km. LoRaWAN is backed by a group including Cisco and IBM, as well as some leading Telcos like Bouygues Telecom, KPN, SingTel and Swisscom. The focus is particularly on harsh RF environments previously too challenging or expensive to connect, such as mines, underwater and mountainous terrain.

Another well backed contender is Narrowband-LTE (NB-LTE) announced in September 2015 with Nokia, Ericsson and Intel behind it, where the focus is more on long range and power efficient communications to remote embedded sensors on the ground. So it still looks like being a case of horses for courses given the huge diversity of RF environments where IoT and M2M will be deployed, with HaLow a likely winner indoors, but coexisting with others outside.

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@nebul2’s 14 reasons why 2015 will be yet another #UHD #IBCShow

Ultra HD or 4K has been a key topic of my pre and post IBC blogs for over 5 years. I’ve recently joined the Ultra HD Forum, serving on the communications working group. That’s a big commitment and investment, as I don’t have any large company paying my bills. I’m making it because I believe the next 18 months will see the transition from UHD as the subject of trials for big operators and precursor launches to something no operator can be without. Time to get off the fence. I once wrote that the 3D emperor didn’t have any clothes on; well, the UHD emperor is fully clothed.

Of course much still needs to be achieved before we see mass adoption. I don’t know if HDR and 4K resolution will reach market acceptance one at a time or both together, and yes, I don’t know which HDR specification will succeed. But I know it’s all coming.

Below is a list of 14 key topics ordered by my subjective (this is a blog remember) sense of comfort on each. I start with areas where the roadmap to industrial strength UHD delivery is clear to me and end with those where I’m the most confused.

Note on vocabulary: 4K refers to a screen resolution for next gen TV whereas UHD includes that spatial resolution (one even sees UHD phase 2 documents refer to an 8K resolution) but also frame rate, HDR and next generation Audio.

So as I wander round IBC this year, or imagine I’m doing that, as probably won’t have time, I’ll look into the following 14 topics with growing interest.

1. Broadcast networks (DVB)

I doubt I’ll stop by the big satellite booths for example, except of course for free drinks and maybe to glimpse the latest live demos. The Eutelsat, Intelsat or Astras of this world have a pretty clear UHD story to tell. Just like the cableCos, they are the pipe and they are ready, as long as you have what it takes to pay.

2. Studio equipment (cameras etc.)

As a geek, I loved the Canon demos at NAB, both of affordable 4K cameras and their new ultra sensitive low-light capabilities. But I won’t be visiting any of the studio equipment vendors, simply because I don’t believe they are on the critical path for UHD success. The only exception to this is the HDR issues described below.

 3. IP network; CDN and Bandwidth

Bandwidth constricts UHD delivery; it would be stupid to claim otherwise. All I’m saying is that by putting this issue so high on the list everything is clear in the mid-term. We know how fast High-Speed Broadband (over 30MPS) is arriving in most markets. In the meantime, early adopters without access can buy themselves a UHD Blu-ray by Christmas this year and use progressive download services. The Ultra HD Alliance has already identified 25 online services, several of which support PDL. Once UHD streams get to the doorstep or the living room, there is still the issue of distributing them around the home. But several vendors like AirTies are addressing that specific issue, so again, even if it isn’t fixed, I can see how it will be.

 4. Codecs (HEVC)

The angst around NAB this year when V-nova came out with a bang has subsided. It seems now that even if such a disruptive technology does come through in the near-term, it will complement not replace HEVC for UHD delivery.

The codec space dropped from a safe 2 in my list down to 4 with the very recent scares on royalties from the HEVC Advance group that wants 0.5% of content owner & distributor's gross revenue. Industry old-timers have reassured me that this kind of posturing is normal and that the market will settle down naturally at acceptable rates.

 5. Head-ends (Encoders, Origins, etc.)

I always enjoy demos and discussion on the booths of the likes of Media Excel, Envivio, Harmonic, Elemental or startup BBright and although I’ll try to stop by, I won’t make a priority of them because here again, the mid-term roadmaps seem relatively clear.

I’ve been hearing contradictory feedback on the whole cloud-encoding story that has been sold to us for a couple of years already. My theory – to be checked at IBC – is that encoding in the cloud really does make sense for constantly changing needs and where there is budget. But for T2 operators running on a shoestring – and there are a lot of them – the vendors are still mainly shifting appliances. It’s kind of counterintuitive because you’d expect the whole cloud concept of mutualizing resources to work better for the smaller guys. I must have something missing here, do ping me with info so I can update this section.

 6. 4K/UHD resolutions

While there is no longer any concern on what the screen resolutions will be, I am a little unclear as to the order in which they will arrive. With heavyweights like Ericsson openly pushing for HDR before 4K, I’m a little concerned that lack of industry agreement on this could confuse the market.

 7. Security for UHD

Content owners and security vendors like Verimatrix have all agreed that better security is required for UHD content. I see no technical issues here - just that if the user experience is adversely affected in any way (remember the early MP3 years), we could see incentive for illegal file transfer grow, just when legal streaming seems to be taking of at last.

 8. TV sets & STBs

Well into second half of my list, we’re getting into less clear waters.

When it’s the TV set that is doing the UHD decoding, we’re back at the product cycle issue that has plagued smart TVs. It’s all moving too fast for a TV set that people still would like to keep in the living room for over 5 years.

On the STB side, we’ve seen further consolidation since last year’s IBC. Pace for example is no longer; Cisco is exiting STBs etc. It seems that only players with huge scale will survive. Operators like Swisscom or Orange can make Hardware vendors’ lives harder by commoditizing their hardware using software-only vendors such as SoftAtHome to deliver advanced features.

 9. Frame rates

This is a really simple one but for which consensus is needed. At a 4K screen resolution the eye/brain is more sensitive to artifacts. Will refresh rates standardize at 50Hz or 60Hz? Will we really ever need 120Hz?

It’s clear that doubling a frame rate does not double the required bandwidth as clever compression techniques come to play. But but I haven’t seen a consensus on what the bandwidth implication of greater frame rate will actually be.

10. Next Gen Audio

There are only a few contenders out there, and all have compelling solutions. I’m pretty keyed up on DTS’s HeadphoneX streamed with Unified Streaming packagers because I’m helping them write an eBook on the subject. Dolby is, of course, a key player here but for me it’s not yet clear how multiple solutions will cohabit. It isn’t yet clear how if and when we’ll move from simple channel-based to scene based or object based audio. Will open source projects like Ambiophonics play a role and what about binaural audio.

11. HDR

High Dynamic Range is about better contrast. Also, the brain perceives more detail when contrast is improved, so it’s almost like getting more pixels for free. But the difficulty with HDR and why it’s near the bottom of my list is that there are competing specifications. And even once a given specification is adopted, its implementation on a TV set can vary from one CE manufacturer to another. I final reservation I have is the extra power consumption it will entail that goes against current CE trends.

12. Wide Color Gamut

As HDR brings more contrast to pixels WCG brings richer and truer colors. Unlike with HDR, the issue isn’t about which spec to follow, as it is already catered for in HEVC for example. No, it’s more about when to implement it and how the color mapping will be unified across display technologies and vendors.

 13. Work flows

Workflow from production through to display is a sensitive issue because it is heavily dependant on skills and people. So it’s not just a mater of choosing the right technology. To produce live UHD content including HDR, there is still no industry standard way of setting up a workflow.

 14. UHD-only content

The pressure to recoup investments in HD infrastructure makes the idea of UHD content that is unsuitable for HD downscaling taboo. From a business perspective, most operators consider UHD as an extension or add-on rather than something completely new. There is room for a visionary to coma and change that.

Compelling UHD content, where the whole screen is in focus (video rather than cinema lenses) gives filmmakers a new artistic dimension to work on. There is enough real estate on screen to offer multiple user experiences.

In the world of sports a UHD screen could offer a fixed view on a whole football pitch for example. But if that video were seen on an HD screen, the ball probably wouldn’t be visible. Ads that we have to watch dozens of times could be made more fun in UHD as their could be different storied going on in different parts of the screen, it would almost be an interactive experience …

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Operators unhappy over Wi-Fi and unlicensed cellular coexistence plans

Controversy has raged for well over a year now over plans by some mobile network operators (MNOs) to extend their spectrum into unlicensed 5GHz bands currently occupied by Wi-Fi. The arguments have been both commercial and technical, centering on the rights of MNOs to compete with established Wi-Fi networks and at the same time the efficiency or fairness of mechanisms for coexistence between the two.

LTE-U enables 4G/LTE cellular services to be extended into the 5GHz unlicensed bands, which is obviously attractive for MNOs because it gives extra precious spectrum without having to pay for it while making it easier to support high bandwidth applications like premium live video streaming. But the initiative, initially proposed by Qualcomm and Ericsson, has gained some traction within the 3rd Generation Partnership Project (3GPP) primarily because many MNOs want to gain full control of heterogeneous networks combining licensed and unlicensed spectrum, so there is a major commercial force here.

MNOs have expressed frustration over Wi-Fi offload, which is necessary to avoid overload on their networks and give their subscribers the best quality experience, but means they have less control over end-to-end traffic. Not surprisingly though those Telcos with extensive Wi-Fi hot spot networks take a different line and are opposed to LTE-U. Therefore we find that operators like AT&T and BT with huge investment in Wi-Fi hotspots but smaller presence in cellular are opposed to LTE-U. On the other hand Telcos that have not bet so much on Wi-Fi but have major cellular operations now support LTE-U, including big hitters like Verizon, China Mobile, NTT DoCoMo, Deutsche Telekom and TeliaSonera.

Notably though some of the world’s biggest providers of mobile services are ambivalent about LTE-U, which some of them see as complicating rather than simplifying the drive towards heterogeneous services combining licensed and unlicensed spectrum. The view there is that Wi-Fi is best placed to occupy the unlicensed spectrum with a lot of momentum and investment behind it. The LTE-U camp counter that the technology can carry twice as much data as Wi-Fi in a given amount of 5 GHz spectrum through use of carrier aggregation via LTE-LAA. This was already defined in the LTE standards and enables multiple individual RF carrier frequencies, either in the same or different frequency bands, to be combined to provide a higher overall bit rate.

This may be true as far as it goes but is largely irrelevant for users wanting to access broadband services in their homes or public hot spots, according to the Wi-Fi community, a view shared by some MNOs as well. Birdstep, a leading Swedish based provider of smart mobile data products enabling heterogeneous services combining cellular and Wi-Fi, argues that the story is not just about the wireless domain itself but also the backhaul infrastructures behind it. Any spectral efficiency advantage offered by LTE-U would be more than cancelled out by inherent inefficiencies in the backhaul. By offering access to the world’s broadband infrastructures Wi-Fi offers greater overall scale and redundancy.

Another Wi-Fi specialist, Turkey based AirTies, contends that LTE-U is just a spectrum grabbing bid by MNOs and should be resisted. Air Ties has developed mesh and routing technologies designed to overcome the problems encountered by Wi-Fi in the real world and these are only going to get worse as unlicensed spectrum reaches even higher frequencies. The next generation of Wi-Fi based on the emerging IEEE 802.11ad standard will run in the much higher frequency band of 60 GHz, which will potentially yield a lot more capacity and performance but increase susceptibility to physical obstacles and interference. It will only work with further developments in the sort of intelligent beam forming, meshing and steering technologies that AirTies has invested in.

It is true that LTE-U proponents have worked hard to mitigate any impact of coexistence with LTE-U on Wi-Fi. In Europe and also Japan they were forced to do so anyway by regulations that required LTE-U to adhere to similar rules over fair access to spectrum as Wi-Fi. These rules insist on incorporation of LBT (Listen Before Talk) into LTE-U, a mechanism originally developed for fixed line Ethernet networks where there was a shared collision domain (it was called Carrier Sense Multiple Access or CSMA). Stakeholders that are not in favor of rapid LTE-U deployment point out that in the old Ethernet days before 10BaseT/switching, CSMA proved inefficient when there were to many devices trying to get onto the same collision domain. Total capacity could drop drastically and this issue could be reborn into the wireless world.

The European Union specified two options for LBT, one the scheme called DCF/EDCA already adopted for Wi-Fi standards and a newer scheme known as Load Base Equipment (LBE), differing in the procedure for backing off when detecting traffic in a given channel.

Naturally enough there has been an assumption in the LTE-U camp that any deployments will be safe if they do adhere to the EU’s LBE LBT standard. But this assumption has recently been challenged by CableLabs in a simulation modeling a million transmission attempts on sets of nodes following the EU LBE LBT rules. The EU LBE turned out to scale badly with increased numbers of devices, with growing numbers of collisions. This will only amplify concerns expressed by broadcasters such as Sky, as well as by some major vendors like Cisco with feet in both the Wi-Fi and LTE camps, that LTE-U poses a threat to quality of service for premium video especially.

There are no signs yet of the LTE-U camp giving up on their efforts to infiltrate the 5 GHz domain, arguing correctly that by definition unlicensed spectrum is free for all and cannot be owned by any one wireless technology. But there is a strong case for holding off from LTE-U deployments until further extensive tests and simulations have been carried out to assess the impact on capacity and QoS in real life situations.

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Google getting it right at last with Android TV

It may still be too early to be sure, but there are signs that with Android TV Google’s connected video strategy is at last starting to look joined up. There is not yet any killer blow in sight, which could only really come from the content angle, but evidence is mounting that Google now has a clearer and more focused strategy that is winning over TV and device makers as well as app developers. The key lies partly in a much mature Android based ecosystem better geared towards TV than was the case when the abortive first attempt called Google TV was launched with much fanfare in 2010.

Then Android was little more than a mobile OS optimized for smartphones and subsequently tablets, with TV supported as a cumbersome add-on that was hard to develop apps for. But the latest version 5.0 codenamed Android Lollipop, first unveiled during the Google I/O developer conference in June 2014, has been revamped for TV with a completely redesigned user interface. This is a significant enhancement based on Google’s own language called Material Design incorporating tools for easy layout of screens with responsive animations, transitions, padding, and depth effects such as lighting and shadow. It comes with new guidelines for developers that make it easier to create a consistent look and feel across the whole Android device constellation, including big smart TVs down through tablets and smartphones to diminutive smartwatch screens. To encourage app creation further, Google sent out developer units, dubbed “ADT-1”, to those that signed up for a test unit at Google I/O 2014.

These nuances were initially missed by many commentators, myself included, at the time of that conference, perhaps partly because the new Lollipop version was still shrouded in a little mystery. My initial reaction to Android TV was therefore quite negative, suggesting it sent confused messages given that Google was also promoting Chromecast and that it offered little more than already existing competitive offerings such as Apple TV, Roku and Amazon Fire TV.

The reason for being more sanguine about Android TV now is not so much that Google has raised its game. If anything it is the opposite in that the horizons have been narrowed to the confines of an operating platform for TV but crucially now aligned with Chromecast as well as with its developer community. What Google has succeeded in doing is strike a balance between encouraging innovation and yet exercising some control over the environment with an emphasis on a consistent UI across all devices, which is something its competitors have not quite matched yet. We have already seen the fruits of this approach through a few OEMs such as Razer, which has announced Forge TV, a set top for Android TV that throws in some of its gaming streaming.

Casting is now at the center of Android TV and pivotal to delivery of content, with the various new boxes, including Google’s own Nexus, Player, being the first dedicated hardware units to support it. This does though pinpoint the challenge of persuading consumers to pay the extra for the full Android TV experience when they can get Netflix and all the basic content they want from Chromecast. Effectively then Chromecast is the entry level version of Android TV with the full monte running on set tops as well as smart TVs, including models announced by Sony, Philips and Sharp at CES 2015.

The killer feature though would be premium live content and all that can be said at this stage is that Google has prepared the ground with its dummy app called ‘Live Channels for Android TV’.  It remains to be seen what will be on it and how far this goes beyond the content currently available either via Chromecast or YouTube. But at least Google is much better placed to strike a major blow in the intensifying connected TV wars.