The EIZO CG2700X UHD colour accurate monitor

I took delivery of my demo CG2700X Eizo monitor over the weekend and ran it through its paces; suffice to say I am pretty impressed.  

It’s a 27” IPS (so modern LCD) 3820x2160 res panel (so not full-4K) but good for TV, and notably smaller than the 31” FSIs and EIZOs so might fit on a QC desk better than the big guys.

So, first thing is to make a matching profile for the Klein K10A tri-stim probe; I've often written before how a photometer is only as good as the profile you make for it with a spectroradiometer - a CR250 in my case.

Interestingly the spectral power distribution is different from the engineering sample I had half a day with over the summer - Eizo tell me they changed the polariser for production units.

So, for calibration I profiled the display in it's native state (so no gamut imposed by the monitor, all colours as saturated as it will make them).

From that (which is 17^3 - around five thousand colours) I made a rec.709 LUT - 100Cd/m²

Rather splendidly, even though this is a brand new model, ColourSpace was able to talk to the patch generator inside.

It is a single-panel LCD so will not have the dark, inky-blacks you’re used to from a Sony HX-310 or Eizo Prominence (but you could buy a dozen of these displays for the price of one of those!).

In terms of wide-colour-gamut/HDR it has decent emulation for HLG and DolbyVision, topping out at about 550Cd/m² (unlike the full 1,000Cd/m² you expect from an Eizo Prominence or Sony HX-310). So could be used for edit/QC/ingest etc. for those standards, but probably not for final grade/mastering.

first column is 10-bit values, second column is light levels

Cages - still important for broadcast QC types; It has three sets of markers; they can be independently sized and positioned. It has presets for all the common aspect ratios and action/graphics safe areas, but you can set them as you want. You can set all line widths from one to six pixels and choose the colours independently.

I’m not sure if it could be any more flexible?! Aside from circular cages, that is!

My demo unit is safely in a flight case and you guys were on the list for offering it to for assessment; you’re welcome to have it for a few days and I will arrive with it to demo some footage.

ASUS ProArt PA32UCX monitor - LUTs etc.

My, my; it's been eighteen months since I paid any attention to this blog. Possibly the longest quiet period since I started writing it in 2003! Anyway - it's mostly down to work (I started Media Engineers at the start of 2020; a few weeks before the pandemic started).

Back in 2019 I was approached by ASUS to point a probe at their new PA32U (the first of their 32" monitors to carry the ProArt product name). It had a lot of issues and I wrote up my findings here. I also made a video showing my LightSpace profiling. 

In fairness ASUS issued a firmware update that took in my recommendations about DolbyVision and HLG. Also, in fairness they made their API available to the guys at LightIllusion which is just the thing - monitor manufacturers (almost) universally seem unable to make decent calibration software. 

SO, spin forward to the autumn on 2021 and an old pal sent me his new ProArt PA32UCX monitor and asked me to set it up for two SDR profiles and two HDR profiles;

1. Rec.709 with a gamma of 2.2
2. Rec.709 with a gamma of 2.4
3. HLG - Rec.2020 colourspace with HLG 1.2
4. DolbyVision - ST.2084 curve

At this point it's worth noting that I didn't have high hopes for the monitor for the following reasons;

1. It's a single-layer IPS (LCD) display with an LED backlight,
2. It's a FALD (so zone'd backlight) - like the Apple XDR it's an effort to make an LCD have a higher dynamic range. A typical 10-bit LCD panel (like an Eizo CG319X) can achieve about 1,000:1 but with a zone'd backlight that can be in excess of 1,000,000:1 but with the downside of halation around edges and transitions. Compared to dual IPS (think Eizo CG3146 or Sony HX-310) or OLED (typ. Sony X300) it's poor-man's HDR.
3. They sell it on the strength of it having "quantum dots"(!) yet it can achieve about the same percentage of DCI-P3 colour space as a modern non-quantum LCD or OLED.  If QD actually exists then surely it should approach laser-projector like primary colours and so get close to Rec.2020 colour primaries? Non-intuitively you need monochromatic primaries to be able to get the largest colour-triangle and that's the promise of Quantum Dots - but since this panel does not have monochromatic primaries where are the quantum effects?!

So - my first thought was that rather than using the hunt & peck four-way controller I'd like to control the monitor from it's software. So, off to download ProArt Calibration 2.0 - first on my Windows 10 calibration laptop and then my other work laptop (15" MacBook Pro 2015 model) and finally my ancient workshop Windows 7 machine - none of them could communicate with the monitor.

I tried several different USB-C cables and eventually I had to resort to a powered hub to get Windows to recognise the device. However, at no point could I get the ASUS software to talk to the display (across three machines, three OSes). Thankfully ColourSpace was able to address the monitor and drive the internal patch generator (more about that later!) - but, first job was to use my CR250 (spectroradiometer) to make a matching profile for my K10A photometer. The reason for this is that the spectro is ultimately accurate but very slow and not good near black whereas the tri-stim K10A is great near black, fast (typ. sub 1 sec per read) but is bedeviled by Specral Power Distribution issues (the K10A is an RGB probe). BUT, with a profile made with the CR250 on the display concerned you can impose spectro accuracy on the photometer.

So, here's the matching profile - for my K10A on this PA32UCX

So, the next job is to profile the monitor so we can make the various calibration LUTs. For a 17-point 3D LUT you need to measure around 5,000 colours (17x17x17) and so even with the fast Klein probe you're looking at two hours. So - I set ColourSpace to drive the internal test signal generator on the monitor and went to make a coffee. When I looked in an hour later I realised something was very wrong; essentially the internal TSG does not seem to generate any blue?!

So, I had to break out my FSI BoxIO which I normally use for patch generation and start again. Two hours later I had a profile and could use ColourSpace to generate LUTs that corrected the monitor to the two rec.709 USER slots.  I saved out the various profiles as Builder Colour Space files (.bcs) and along with the LUTs I made you can grab there at https://tinyurl.com/yej2cs5j

Now to the HDR settings and I discovered that you have to toggle the HDR-flag in the HDMI stream to get the monitor to switch into HDR mode which is plainly stupid for something that isn't a TV! No matter; break out the AJA Hi5-4K+ and use that to switch the monitor into both HDR modes.

Repeat the profile in ColourSpace and then generate the DolbyVision and HLG LUTs and use CS to upload them to the monitor. The results are not bad; here's a photo of the Eizo's luma scale in DolbyVision mode (so display-referred) and it shows around 650 Cd/m2 (not the >1,000 as their website suggests) once calibrated. In RAW/uncalibrated mode it can hit more than one thousand.

Last thoughts;

1. If you put it into HDR mode, then switch the i/p to an SDR signal, disconnect/re-connect (which you have to do) it will then let you recall one of the SDR USER settings (so 1 for 2.4 gamma, 2 for 2.2 gamma) BUT it never takes the backlight back down to SDR levels - so you get rec709 with 500Cd/m2 white. You have to manually wind the "Brightness" figure back from 100 to 10
2. "Brightness" is mislabelled - it should be "Backlight" or somesuch
3. Brightness is actually called "Black Level"
4. Their software proved useless - without ColourSpace I would have been left high and dry. 
5. All this fiddling about took days (whilst I was doing other things) - I would not want to have been faced with this at a client's site. I won't be taking bookings to calibrate these monitors.

It's like a computer monitor they've hit hard with a hammer to kinda behave like a broadcast display but they haven't listened to everything the broadcast guy told them - I would not buy this monitor - for Rec.709 I'd use an Eizo CG-series and for HDR I'd use an LG or Panasonic OLED TV.

What I saw at IBC2019

Eizo CG3145 “mk.2?” – Revision of the current model “Prominence” monitor - see my post from last year.

It’s exactly the same dual Panasonic IPS (LCD) display module and modulated LED backlight as the current version (and indeed the Sony X310 replacement for the X300) with the following upgrades;

1. Quad 3G and single-link 12G inputs for current gen 4K/UHD/HDR standards. If you need to go to 18G standards (so 4K, 12 bit, RGB and 60P) it still supports HDMI 2.0 and DP. Once nicety is that it has SDi out and can convert signal standard as an active loop-through (but not converting colour space, sampling structure etc – obviously),
2. Internal probe; a higher quality photometer than the 319X but I’ll have to test it against a “proper” probe before we make comment; they assured me ColourNavigator’s “sensor correlation” function would work as other CG-series displays. See my video.
3. Three user-defined cages and BITC as per Sony’s 4k monitors – this has been mentioned by several facilities as reasons why they won’t leave Sony – aside from the BITC feature having been broken in the Sony displays since v.2 firmware I don’t believe grading room displays need either of these, but it’s good to have an answer (I’d say exactly the same as point 1. Above)
4. Much nicer control via a big knob on the front.
5. Price – will be the same as the current CG3145
6. Availability – they reckon there will be pre-production demo examples in January and supply at start Q2.

They made some point about having improved the FPGA code in the panel for better sharpness – sounded like marketing waffle; and in truth savvy customers don’t want a monitor “sharpening up” their pictures; pixel-to-pixel is what’s needed; brutal honesty rather than the picture processing you get on a domestic TV.

Emerald KVM system from Black Box; it comes in three product skews;
https://www.blackbox.com/en-us/products/black-box-brand-products/kvm/control-room-kvm/4k-kvm-over-ip-switch

• The basic – tops out at 2 x single-link displays (1920x1200) 
• The “professional” – same performance but has tighter integration with their manager
• The 4K – supports a single 4096-pixel wide display.

Points to consider;

1. Price – the basic and professional are very akin to Amulet pricing (bear in mind Amulet Tera2 products do 4 x single link or 2 x 4K displays) – so typically £1,000 per end-point (sender and receiver); Amulet external T2 would be £1,400 (sender) + £700 (receiver). The 4K product which is what now competes with DX-H4T/DZ4 from Amulet is around twice the price (about £3,900 for sender/receiver pair). Add onto this the cost of a broker (their own 1u Linux box) AND they heavily push you to Black Box managed switches (essential if you’re using all the broker features),
2. Encryption – AES256 with key-exchange is the clear via the broker’s database; we couldn’t sell this to anyone who is looking at a TPN audit,
3. Bandwidth – max’es out a gigabit Ethernet (in fact you need the second NIC if you want to use two screens); remember, Amulet plays nicely with internet-type bandwidths
4. Switch requirements – As mentioned, BlackBox manages switches preferred, but whatever you use jumbo frames and IGMP-snooping is required. Amulet plays nicely with all layer-2 ethernet switches.

Niceties;

• Broker is better to use than Tera connection manager
• ZC supports both PCoIP and RDP (their protocol is Windows RDP!)
• As you’d expect from a modern KVM it is reasonably transparent, but full-screen HD video playback was (I thought) worse than Amulet (and remember Amulet tops out at 200Mbit/sec rather than the 2 x GigE that the Emerald needs)

So in fairness I don’t think there is any scenario (other than owning existing plant) where we could sell it as a better option than Amulet (or a Teradici option).


Streambox’s DolbyVision remote workflow
http://www.streambox.com/post-production

StreamBox have implemented eCMU functionality in their Chroma range which means they can take the DolbyVision metadata across the IP-SDi feed and decode the rec.709 fold-down data at the far end and display dual-6G outputs on and HDR monitor and a rec.709 display (typ. a decent TV). The powerful thing is that by having the Dolby tone-mapping algorithm with all the lift/gamma/gain tweaks in the HDR stream they can produce a pixel & colour accurate SDR version at the far end with no extra bandwidth required. Super-cool.

Canon DP-V3120 4k/UHD/HDR grading monitor
https://www.canon-europe.com/video-cameras/dp-v3120

We sold a few of the earlier gen Canon DP-V3010 4k displays and although they were good 4k displays their HDR abilities were more limited than the X300 – in fact today they would be an equivalent to a £3.5k Eizo CG319X.

The new monitor uses the same Panasonic panel & backlight as the Eizo and Sony, but in this case it is a single-layer IPS which means the blacks are probably not as good as the CG3145 and the X310. I’d have to test that when we can our hands on one.

• 2,000Cdm^-2 max light output – probably because it’s only a single layer, they’re letting all the light through. Not sure why this is a benefit as nobody (Netflix, Fox, Warners) are specifying 2,000Cdm^-2 deliverables and the next bump to DolbyVision will be to 4,000Cdm^-2 so this seems to be neither fish nor fowl – much like the Flanders 3,000Cdm^-2 monitor.
• Tone-mapped false colour display – this is very nice; As far as I could tell this is nerly as good as Leader’s “CineZone” display but available in the monitor.
• Same set of inputs as the new Eizo
• Sub £20k price tag

ColourSpaceCMS colour management and LUT building software.
https://www.lightillusion.com/colourspace.html

We sometimes sell a LightSpace license with Klein colour probes and I tend to then provide a day’s training (doing it next week at a customer's).

• Much more modern interface – lots of people complain that LightSpace looks a bit 1990s and things like loading LUTs and talking to patch generators takes a few mouse clicks rather than being auto-detected. ColourSpace seems to address all of this. I've never found this to be an issue; if you've spent thousands on a probe and software you should really get familiar with it.
• Profiling engine can run whilst you are manipulating LUTs – very cool; will go some way to addressing the two hours of thumb-twiddling I have to do whilst profiling a display.
• Multiple probe support – you can be profiling two displays at a time; but with probes costing >£6k I wonder who will use this?! Monitor manufacturers at their factory, probably.
• Price – near-free upgrade from LightSpace depending on age of license.

We never really offer LightSpace as a product by itself; always as part of a package and as part of the colourimetry training day.


Leader LV5900 – 8K test and measurement
https://www.leader.co.jp/en/event/7318

• 8K (so quad 12G) version of the LV5600/LV7600 series we sell.
• Price – silly money! >£50k basic

AJA Image Analyser – HD/UHD/4K/HDR test and measurement
https://www.aja.com/products/hdr-image-analyzer

They’ve been selling this for a year as a competitor to the Leader but I don’t know it’s HDR abilities.

• Quad-12G – now can operate as a 4 x 4K machine; perhaps an OB that is sourcing Slog3 cameras and delivering both HLG and rec.709 would find this udeful?
• Price - £16k (so cheaper than an HDR/4K optioned Leader)

Also – all the Hi5-4K+ and associated boxes now support Dolby metadata passthrough so no more hooking up the USB control to force displays to switch between rec.709/PQ/HLG. Nice.

The Bryant Unlimited cable manufacturer's meal - the highlight of my professional year!

Calibrating the Calibrator - Colour management with Eizo CG319X

I've spent a lot of time demo'ing these monitors recently and the thing that tickles customers the most is correlating the internal sensor to an external probe.

https://youtu.be/LB6HFOBJU2c

 

Is there an HDR mastering display that costs less than £20k? Not yet.

I was asked to take a look at the ASUS PA32U monitor - a 32" display that (when I first saw it last year) was initially an sRGB, Adobe RGB, HDR10 high-end graphics/gaming monitor. It comes in at sub £2k and so is expensive for home or office use but almost free from a film/TV perspective. Most interetsingly it could hit >1,000Cdm^-2 peak white and unlike OLED displays (typ. Sony BVM-X300) it doesn't suffer ABL as more than a small percentage of the display hits peak white.

I gave the manufacturer a few pointers - essentially if it is going to have any application in film and TV it should at least support HLG and DolbyPQ. So, just before christmas a new itteration of the monitor arrived and here is a little video.

A few things to note;

1. Terrible "blooming" near black; if it was a CRT it would be akin to bad internal reflection within the tube.
2. The blue primary is not as good as it should be - it can't even hit 100% of rec.709
3. Ironically, however, it does manage 84% of rec.2020 - just shows you can't get too hung up on very saturated colours,
4. There is some sort of noise-coring going on; you should be able to disable that in the menues.

LightSpace reports; http://www.engineersbench.com/phil/docs/ASUS_PA32U/

https://youtu.be/hYCJh9ujhxw

Why I wouldn't buy a Sony BVM-X300 in 2018 (if it was my money)

For a couple of years the Sony BVM-X300 has been the 4k/HDR monitor of choice for Soho edit and grading suites. It is an OLED monitor and can (with some limits) hit 1,000 Cd/m² peak white in it's HDR modes (which include HLG, Dolby PQ and SLog3 camera gamma).

It was the first monitor to be widely regarded as good enough for Dolby Vision mastering (and by extension Netflix deliverables). It was around the £20k mark when it launched, but by last year the price had crept up to mid-twenties and with the v2 of the monitor (which brought a second quad-SDi input and an HDMI input) which launched a year ago it now lists at £32k; but we all know nobody ever pays list for Sony...!

In recent months I've really taken to the Eizo CG3145 which (although an IPS/LCD monitor) is broadly similar in spec to the Sony, but; bear in mind the X300 suffers the following;

1. Noise in the blacks; when I calibrate them I have to do blacks at 5% grey to get a clean reading (and my probe goes down to 0.01 Cd/m²) – the Eizo will read cleanly at 2% grey. Watch this video (hosted on my Twitter feed) - it's an X300 around 3 Cd/m²
2. Max. 8% peak white before the orange PSU-fault LED comes on and the display starts to dim/de-saturate in HDR modes; at the recent Jigsaw24 I showed the "OLED killer" which you can get here.
3. Two years in and several Soho X300s are now showing burn-in (particularly where the 3840-pixel UHD and 4096 pixel-4k rasters differ) 

£10k less list price and available now (the X300 is in such short supply that you can't get one in London currently) also add to the Eizo’s advantages. Integration with LightSpaceCMS (pretty much the industry standard for colour management) is very tight whereas the X300 only talks to Sony’s very clunky colour software (no LUT management, six-point calibration only). 

The Eizo easily allows LUT upload; this SLog3 (in slot 8) was imported via LightSpace.

 

ColorEdge PROMINENCE CG3145 is the first HDR monitor in the world to have its HDR and SDR reproducibility evaluated and awarded by the German Broadcast Technology Institute.

The Eizo has recently been certified as both a Dolby Vision mastering display as well as having Netflix's blessing.

One objection I've heard is that the X300 covers 85% of rec.2020 whereas the CG3145 only covers ~83%. It's the kind of objection that someone with a poor grasp of colourimetry makes. My answer to that is "MacAdam ellipses" - look at the Wikipedia article and tell me anyone can see the (Just Noticable!) differences.

At the recent HDR Summit at Dock10 in Media City, Salford we had more than ten HDR-capable displays.

A few notes on DolbyPQ & the new 4k AppleTV and TV High Dynamic Range.

STOP PRESS! 27th Sept. 2017 Update;

So it turns out that the new AppleTV does support HLG.

- Why did it take somebody hacking around with a firmware update to discover it; perhaps big corporations (Apple and Dolby) talk and would rather not highlight the fact?


HDR is half my life at the moment; the distinction between "Display Referred" and "Scene Referred" video is lost on most people, but is pretty central to understanding why the BBC/NHK "Hybrid Log Gamma" system is ten times more appropriate for television (non-theatrical video) vs anything based on the SMPTE 2084 (AKA Dolby/HDR10 etc) curve.

For my presentation on "intro to HDR for TV" download here.

1. Display Referred HDR makes no sense for TV (when I say TV I mean all non theatrical video). DolbyPQ makes video dimensioned (so code values actually represent light levels) which makes a lot of sense when you have complete control over the environment you're viewing in - a theatre. To define where black and white sit (and actually assign light-levels to them) is problematic for TV workflows. Remember, you have to give the colourist/racks-engineer/domestic-viewer the liberty to set black according to the room. Although BT.1886 is commonly accepted to mean 100Cdm^-2 peak white a lot of colourists drive their rooms at 80Cdm^-2 and at least one film guy I know prefers to work at 60Cdm^-2. Also - what happens in three years when everyone is selling TVs with specular highlights that can hit 2,000Cdm^-2 and people can see the difference between PQ content mastered with peaks at 1,000Cdm^-2 ( the current standard) and new content? The same will be true all the way up to Dolby's max light level of 10,000Cdm^-2. Dolby at least has the benefit of dynamic metadata to allow or this, but HDR10 is static metadata and so has all the problems of display-referred HDR with none of the DolbyPQ benefits.
2. BBC/NHK HLG is a much more pragmatic solution as it doesn't assign code-value to light-levels (when has that ever been a thing in TV?!) and allows HDR content to look good on all devices capable of displaying it; tablets, TVs, laptops etc. It also allows the broadcasters to make a gradual change to HDR. None of the broadcasters I've spoken to have any appetite for having Dolby CMUs all over the place to manage the metadata (which, being a licensed format, they would be obliged to have). HLG also tracks 1886 for most of the curve (to around 65%) which means conversion to/from is easier and even when you get it wrong the pictures look OK. It's why scene-referred video makes sense for TV.
3. Having seen the same SLog3 (so camera HDR gamma) played out from Transkoder in both DolbyPQ (mastered at 1,000Cdm^-2) next to the same machine converting to HLG with two Sony X300 monitors set for the appropriate gamma curves and the same Rec.2020 colour calibration you could not tell them apart in a blind viewing. 
4. It's typical Dolby - they are trying to dominate the domestic space by shoe-horning their theatrical format into TVs. Broadcasters get hobbled with licensing costs, onerous upgrade requirements and pictures that are locked to whatever version of PQ/HDR10/HDR10+ they were mastered for rather than allowing the display to make the best of what it's given; scene referred pictures.
5. The good thing about HLG is that rec.2100 ratifies it, the DVB have too. It's also trivial to upgrade HDR10-capable sets to support it (unlike PQ). I imagine it'll be the case that broadcasters will deliver HDR (for the reasons mentioned) and either you have to upgrade your TV (but pretty much all the current ones support it out of the box) OR your STB will do the conversion.

Which is why the new 4k AppleTV is a damp-squib...   

Calibrating monitors for HLG-1.2 High Dynamic Range working

I've now done a couple of Sony BVM-X300 (4k/HDR OLED panel) monitors for HDR-TV deliverables to the BBC. The Beeb are behind the Hybrid Log Gamma standard, currently at 1.2 for broadcast. It's benefits over Dolby's 10-bit version of their Vision HDR system (also called DolbyPQ) are many and rather splendidly the DVB as well as most manufacturers are now behind HLG. I'll write further about why a scene-referred system is a better bet for domestic TV than a display-referred one (like DolbyPQ) but I just wanted to get down some notes on monitor calibration for HLG.

So first up you need to get the monitor into HDR mode (the correct one! As of v.2 firmware the X300 supports several; the camera gammas; CLog, CLog2, SLog & SLog3 as well as the deliverable standards; SMPTE-2084 (DolbyPQ) as well as SMPTE-2100 (HLG 1.2).

You'll notice the EOTF setting (lit. "Electronic - Optical Transfer Function") is NOT set for HLG 1.2; this available but in the current v. 2.0 firmware it is wrong. Select HLG (Variable), click the know again and dial in 1.2

Next up display a 50% grey field (100% can't be done as the monitor power-limits to stop 1,000Cd/m² being displayed across a lot of the screen) and point your probe at the display. Remember that unlike DCI-P3 we are still at the 6504K white point of tele. However - at 50% grey we should be seeing low-50's Cd/m² being emitted from the screen. 

You might have previously heard Sony's "best practise" (sic) advice of setting 50% grey to 100Cd/m² but this is wrong. Look at the graph; this is the result of profiling an X300 (and they all seem to do it consistently) and notice what happens over the last couple of hundred Candelas at the top end. If you set 50% grey to 100Cd/m² you get loss of detail in the specular highlights. For the correctly 1.2 HLG curve you need to set 50% to around 50Cd/m² to 55Cd/m²- remember the Y-axis on this graph is logarithmic. 

The one display I had previously followed the Sony advice for was sufficiently out of it's linear range that the dark-greys drifted red minutes after I finished adjusting the monitor and (like all OLEDs) the noise in their blacks is sufficient to make the final tweak to 6504k hard work - the Klein probe was having to average over 32 reads to accommodate the OLED panel. Remember - the K10A is accurate to less than 0.001 Cd/m² and not the 1.0 Cd/m² it reads at 10% up the curve of HLG 1.2

So - once you have those under your belt you can PLUGE the display to set blacks correctly for the room (what did I say about scene/display referred?!) and then set about getting the deep greys and the 50% colour balance correct. I've done this now on two X300s with BBC R&D engineers in attendance and they have given this method their blessing!

For a probe I was using a Klein K10A with Klein's own ChromaSurf software. If I get the chance to profile an X300 for myself I will do it with LightSpaceCMS - still the choice of champions for display profiling and LUT-building. They also have an excellent article introducing HDR.

LUTs are sometimes not the answer.

As I often tell people; a LUT can only reduce the dynamic range of a display. For the most part that needn't matter, particularly if you have the whole of the DCI-P3 (or a decent chunk of Rec.2020) in your monitor. Applying a look-LUT to simulate a delivery style is one thing but increasingly people see LUTs as the first answer to monitor calibration rather than getting the display to as close-as-possible before profiling/creating a LUT. Hugh and I did a podcast on the subject.

A problem I've recently discovered with a monitor's internal Rec.709 LUT is that although the monitor has a huge gamut in it's native mode (which you can see from this recording of ChromaSurf's output) but the 709 presets have trouble.

Notice how it can reach a full green value of 0.1879, 0.7317 (Rec.2020 calls for 0.170,0.797); you'd think there would be absolutely no trouble getting Rec.709 right, and in fairness the primaries are fine. BUT, when I use both primary and secondary colour ramps;

I wind up with some distinctly funny looking banding in the secondary colours.

On this 'phone photo it is particularly noticeable in the yellows, but it's there in the cyan and magenta ramps as well. The fault isn't there when the monitor is in native mode (or indeed P3, NTSC or EBU), only Rec.709 (ironically the only colour space we really need for TV!).

So, I'll have to profile it in native mode and spin a 17-point 709 LUT as the one from the manufacturer is clearly got problems.

Another way of stress-testing a LUT is to use the TrueColor LUT stress test image.

Stuck pixels on LCD & OLED monitors

Because they're semiconductors (and pretty tiny ones at that!) the pixels on modern HD monitors can become "stuck" such that you get a dot that is either black or white (in the case of all three sub-pixels; R, G, and B being stuck on or off) OR a primary (or secondary) colour where less than three of the sub-pixels have stuck. It usuall looks something like this;

see how the blemish aligns perfectly with the pixel raster

You have to get your face about an inch away from the screen to see a single stuck pixel on a 1920x1080 25" display, not exactly edit/grading viewing distance!

 

A piece of software that has helped me in the past is JScreenFix which is a little Java app that allows you to hook up your laptop to the monitor - thankfully all current model broadcast displays have HDMI but you might have to make arrangements (DVI to SDi converter, for example). 

Here's the interface as I used it today to mark three dead pixels on a broadcast OLED;

This is the random pattern (video noise) that it fires at the hundred or so pixels around the area of interest. The idea is that you leave it running for a while and hopefully it will provoke the thin-film-transistor (in the case of an LCD) and the diode (in the case of an OLED) to recover it's ability to start switching again.

In the case of the monitor I had a go at today I was able to clear down two of the three stuck pixels, but the final one that remained resistant to repair was interesting; a photo shows it to be probably some contaminant in the panel rather than dead pixels or sub-pixels;

the blemish seems to be in the inter-pixel space?

Boland's new hi-brite 7" camera/on-set monitor

It seems to be a thing for small on-set/camera monitors that they should have a hi-bright mode when being used in non-edit environments. The Boland BVB7a is an excellent little monitor and can be powered from the camera's 12v battery feed as well as coming with a DC PSU. It can take SDi (single or dual-link) as well as HDMI and composite (yes!). I shot a little video of me profiling it's colour capabilities.

Colourists are the last people who should have a say on monitors!

I was recently in a decent grading room - Dolby PRM 4220 monitor and I was demo'ing a Boland BVB25 OLED display. The demo unit had come back from a try-out at another customer's and I hadn't had a chance to check it's calibration (Rec.709, illuminant-D yada yada...) and so I grabbed the colour probe kit and calibrated it whilst chatting to the engineer and colourist. Once done I looped it off the Dolby to see how they compared and they were quite different! The Dolby was sat-up, over-saturated and a bit red-in-the-whites. The conversation went;

Colourist:"It doesn't match my Dolby",
Me:"…you just watched me calibrate the monitor for Rec.709",
Colourist:"It's wrong",
Me: "Is the Dolby set for Rec.709?",
Colourist: "No, I feel that when I export Quicktimes for customer approval how I have the monitor set now matches what they see better"

 I also have the same convesation about black levels endlessly. An online editor had a go at me because I'd left his monitor "too crushed in the blacks" - here is a frame from his timeline;

It is a continuous battle to persuade people that monitor calibration is NEVER a matter of opinion, rather it is defined by measurable technical standards and when I calibrate a display it is correct. Your material may well not look how you want it, but don't corrupt your monitoring pathway to make your project look good.
Often I'll ask the colourist what standard they want the monitor calibrated for; it's rare that they know what I'm talking about, but they'll often venture an opinion that their display is currently "too cool" or something (quite how they know without a reference I'm not sure?).

I suppose a lot of this is down to the fact that colourists are people who have to be very confident in their ability and are paid handsomely for what they do. However, they have to realise that their mojo doen't extend to how their monitors are set up. When I demo a monitor my heart sinks when someone says "we'd better let the colourist have their say" - monitoring is not about creative magic, it's about compliance.
This December I've calibrated over thirty customer broadcast displays; I've been there/seen that more than you!

4k and UHD cabling and signal standards

I've had to dig into signal transport for 4k/UHD over the last week or so. Essentially I have a test-signal generator (SRI Visualizer TG100) running at a maximum raster of 4096x2160 at a maximum of 25 progressive frames/sec (and only 4:2:2 colour sampling; Y, Cr, Cb) with a 6G single-link output (so really 4 x 1.5G links) and HDMI 1.4 (so the same raster as the SDi). The monitors are the 24" and 30" Canon IPS 4k native monitors.

The Canon monitors will take quad-link HD/SDi and (in the case of the 24") HDMI. So, feeding the SRI single-link into a Blackmagic 4k multiplex (to produce quad-link) and then into the Canon produces four quads in the wrong colour-space!

 For an insight into what the multiplex is doing it's worth looking at the two standards for quad-link SDi. Put aside if it's 4 x 1.5G or 4 x 3G (that allows an increase to 50 or 60P OR 4:4:4 colour). But, in this case we're de-mux'ing a 6G to 4 x 1.5G signals. 

The original 4k-over-four-BNCs standard

The more recent standard; each link looks like an HD version

Clearly the converter is producing 2SI but the Canon expects SD quad-link. In fact the guys at Canon tell me they have a firmware update early in 2016 to address this. The other error is that the Canon has mistaken the 4:2:2 video as RGB - but it has at least got the raster correct.

So, what to do? Well, by throwing in another converter and taking the HDMI out of the SRI means the BM mux will get an older SD quad-link input;

This produced what we need; clearly HDMI has not concept of mutliplexed pixels and so we're now fully in SD quad-link;

tugging BNC no.4 shows the monitor is now in quad mode

The monitor gets it all right

The other thing that you have to pay attention to in "True 4k" displays (for the film snobs!) is that feeding 3840x2160 signal into a 4096x2160 monitor and letting the monitor scale-up to fill the line risks killing your resolution;

The aliasing should only the present in the top-most block, the other alias frequencies you can see here are due to my iPhone's camera!

Some very strange aliasing when a 3840-pixel line is mapped to 4096 pixels

As ever with display devices, pixel-pixel (native resolution) is always preferred

UHD-TV test material; how I'm going to demo monitors

After all the monkeying around with the Canon monitors last week I decided I need a decent variety of clips to show off UHD displays to the best of their ability. For some reason customers are not satisfied with just seeing test signals?!

So - although I have the TG-100 for uncompressed 4k test signals (the Visualiser really shows all you need to know!) and I can show:

• Resolution
• Colour Space
• Temporal performance
• Dynamic Range

So, I went looking for some well shot UHD footage at the TV 4k raster of 3840x2160 (I know, all you DCI-snobs, "true" (sic) 4k is 4096x2160). The Harmonics site has some nice short uncompressed YUV-planar format videos; http://www.harmonicinc.com/resources/videos/4k-video-clip-center#4k-clip-center - But don't expect your laptop to be able to play these guys! At 12GBits^-1 they are monsters and so for ease of use you may want to compress them down to a more manageable 500MBits^-1 (or so) using GLYUVPlay which can be found at Henryk Richter's site. In video coding research, standalone implementation and testing of video codecs often involves the use of raw YUV streams. Since these streams can be parsed and generated by very simple means, raw YUV files are very common in video codec standardization and development. 

I have made the H.264 variants and you can find them on my Google Drive folder.

Canon's 4k Native IPS television monitors

I had an excellent half day with Canon's UK imaging display guys to look at their DP-V series 4k native displays. To my shame I had assumed that they would be like the HP Dreamcolor or Eizo ColorEdge series monitors which are advertised as being suitable for film and TV work but as I've often said; "..an SDi BNC and a preset called Rec.709 does not a broadcast monitor make"!

In the case of those two manufacturers they assume that taking their print-prep graphics display and making it SDi capable is all that's needed; forget proper RGB linearity and a controlled white-point. In the case of the HP they still advertise it at 250Cd/m² for white (four times what it should be - you can't grade with that) and every time I've had an Eizo to play with I've found the same. Even employing a LUT to tame something like that is a bad idea as having to take 250Cd/m² down to a more sensible 80Cd/m² means you've lost two stops (12dBs, two significant bits) of dynamic range; not what anyone wants.

So - native 4k displays using LED-backlit IPS-LCD and not OLED. Every display technology suffers issues and although I think the poor inherent RGB tracking of OLEDs is entirely addressable in a LUT (which is why I love the Boland BVB25 for colour-accurate TV work) OLEDs are noisy once you get very close to black thus limiting their dynamic range (fine for 10-bit TV work; but for 16-bit HDR film imagery, not so much - yet!). Canon has consequently chosen IPS-style LCDs (with a level-modulated LED backlight). The LED backlight is the same technology as that used in the Dolby PRM-4220 grading monitor which is how they achieve the high dynamic range with a possibility of >1000Cd/m² for specular highlights in HDR 16-bit video. I got to see the originators of this technology, Brightside, back in 2005. 

So, proof of the pudding etc - I profiled the 24" edit suite variant and it was very close to the Rec.709 spec (the fact that I left LightSpace set for a 2.2 gamma whilst the monitor has a true BT.1886 gamma for HD rasters may be to blame). With 4k source material the results look great.

 I started at 2k to see how it did

 At 4k I can only manage 25 FPS at best!

Zooming in on the frequency grating shows aliasing, but only on the camera pics, I couldn't photograph it with my 10Mpix camera without catching aliases in the camera's OTF.

Getting closer gets a bit better, but to the eye the resolution is astounding

 

The Sarnoff ladies at true-4K

 

I profiled the display at 17-points so 5,000 measurements take around two hours with the Klein

 

Looks pretty good for greyscale performance, and I suspect if I set LightSpace's gamma correctly it would be better

The coloured dots are rec.709 and the big cube is the gamut of the display; it covers the colour space nicely.