UVW Series Error Codes

Always getting asked these - and I can never remember them as well as I could those for the BVW-75P

Optical link hacking

I saw this article on The Register and thought it was worth commenting on. Basically they've found that you can bend a fibre and get enough signal out of the bend to reconstruct the data stream. I can only imagine that this has been tried on mono-mode cable only (mono-mode transceivers are a lot more robust when it comes to dB loss). If you've ever ended-off a fibre you know how fragile the glass is - having to open up a loose-tube cable, scrape off the coloured ident paint, attach an optical coupler and bend the fibre just enough to get leakage but not have it break would be a real feat! I know in military applications they de-tune the sender to the point where the receiver has less than 3dBs of tolerance - any mucking about with the cable makes the link fall over and an engineer investigates. That's why the MOD ban UDP traffic on their fibre networks - they know the 3-way TCP handshake requires a link that hasn't been interfered with.
I started thinking about whether you could try this with multi-mode fibre - it's a lot thicker (62.5 microns as opposed to typ. 9 microns) and so physically is a lot easier to manipulate. However, after spending last weekend measuring the response of multi-mode cables that had been only mildly abused I realised that where you can tolerate 10dBs of loss on a mono-mode fibre (even at 10 gigabits per sec) you rapidly run into trouble at even half that data-rate with multi-mode fibre.
So I think I'll consign this story to the category of you might be able to do it in the lab but the practicalities are too troublesome.

How things change

I was working over the weekend at a facility that has a fibre infrastructure that looks like it was done by people who lack opposable thumbs! They want an assessment of how easy it will be for them to move up to a four gig Avid Unity. Anyhow - while there I spotted this BKSTS poster about film formats - I was tickled by the how assured the authors were of film's future as an origination format.

Film is the ideal origination format for HDTV

Which I suppose was true up to a couple of years ago if resolution was your only concern - film has poor motion rendition compared to video but it does have more detail.
The day before I was having a coffee with my good chum Dan Sassen - chief engineer at Envy. He told me an interesting thing - apparently Arri UK have just taken delivery of seven extra D20 digital cameras to service the requirements of the European film production community - they now have fourteen of those cameras for hire. Fantastic you might think - digital cinematography takes another leap forward - clearly the demand to shoot at 4k has doubled in the last year or so. However - compare this to the number of pre-orders for the Red camera - 11,000 (in case you were wondering!) and I think film as an acquisition medium will die even quicker than I thought.
It seems HD is the ideal acquisition format for film!

Real Alternative

I love the BBC listen again feature on all their radio websites.

I hate Real Player in it's various incarnations.

This is the solution - and it works!

Clarke on Channel 9

Dr Sneath visits James Clarke, one of the program managers on the Expression team to see an amazing end-to-end demo that shows the power of Expression Media Encoder and Silverlight working together.

I used to work with him!

Burn-in on Sony LMD-230 series HD TFT monitor

It's not a great image (and I had to crank down the gamma to get it even visible) but what you can see here is the residual burn-in of colour bars on a Sony LMD-232 high-definition monitor. I would not have believed it until I saw it at the facility I was working at today. This monitor is two years old and I don't know if this kind of distortion is correctable. It must be the TFT panel itself - there is no way the backlight could take on the effect of bars. You can just see a yellow bar (where the blue bar would be) and where the green-magenta transition is you can see a magenta-green line. I do remember Martin Euredjian from eCinema Systems telling me that if you switch liquid crystal faster than the 15mS recommended by the manufacturer you run into trouble - the transistors become lazy and loose the ability to switch back entirely. This looks like what I saw on this Sony display.
While on the subject I thought I quote Martin on another of his TFT pet hates - grey-grey response times for monitors;

...this brings me to a topic that is being greatly abused by several monitor (and panel) manufacturers. To clarify, "monitor" means a finished product that an end user would purchase. In contrast to this, "panel" means the raw LCD element use by monitor manufacturers in fabricating their product.
This business of pixel response time has to do with how quickly the pixel is able to fully turn on (white) and then off (black).
If you were clicking out Morse code with a flashlight, you couldn't go any faster than the time it took for the light bulb to go from full off to full on and then full off again. For example, an LED flashlight can do this significantly faster than a conventional filament bulb flashlight.
In the context of LCDs, the only response time number that is of any relevance to film/video applications is a measurement taken from black to black. In other words, start with a black display and flash it to full white, returning to black. This is the only number you want a display manufacturer to quote you for response time.
Marketing guys have been known to bend things --a lot sometimes-- and so, it should come as no surprise that some are quoting response times that are simply not achievable within today's constraints. The latest one I heard during NAB is 6 milliseconds. I had people coming to the booth saying "how come yours couldn't do 6 milliseconds, "x" are saying that theirs do".
The critical question here was "Is it from black to black?". When asked, the answer was a resounding "no". People are taking measurements from some level of grey to another level of grey and quoting this as the display response time. You might as well be quoting the time it takes the average person to sneeze, because it would be just as irrelevant. Be aware of this and don't fall prey to contrived marketing.
Best-of-class response time today is somewhere around 15 milliseconds for all LCD's manufactured anywhere in the world. Why? Because there is only ONE liquid crystal fluid manufacturer that supplies fluid to the makers of ALL the good panels. The response time is largely a function of what the fluid can do. Today, the fastest fluid available can do about 15 milliseconds. Remember that and smile as a sales guy quotes you 2 millisecond response time. It might happen.

If you're interested you can read some of the other things he has to say on the cinematography mailing list.
If you're new to TFT displays for television and want a very good overview of how they work check out plasma.com

Bye bye Windows server, hello Linux!

Just a quick post to say that the Windows server (that has required a lot of maintenance AFAIC) that has sat in the cupboard under my stairs for the last six years has been pensioned off and from now on this blog (as well as several other sites I look after) will be hosted on my little embedded Linux box (running a 2.4 kernal compile of BusyBox).
It was a relatively painless switch-over with only one site falling foul of a path that contained upper-case letters that I didn't notice.
Now I can hold my head up in the company of other geeks!

My standard recruitment questions for engineers

Video:

A DigiBeta machine has an 8-Field lock switch – why is this an anomaly on such a VTR and what does the switch do?

This question would really sort out the sheep from the goats! This shows if they know anything about PAL and how VTRs lock their servos. If they can give a credible explanation that uses the phrase “vertical interval sub-carrier (VISC)” and they appreciate that the VTR can re-encode the PAL o/p with the same phase of sub-carrier that was used to decode it then give them the job there and then!

Audio:

0dBu = 4PPM = -18dBfs

What do these expressions mean and why is this equation significant?

Do they know anything about audio measurements and how analogue and digital levels relate? If they can explain the terms dBu and dBfs then all the better.

What is the significance of balanced audio and why shouldn’t you plug unbalanced equipment into a balanced distribution?

Kind of important – if they mention “common mode rejection” in relation to balanced audio hire them! If they don’t know about the risks of unbalancing a whole facility then worry!

Networks:

Hub, Switch, Router.

What are the differences and similarities between these gadgets? How would you use each?

The whole world runs on packet switched networks – do they know anything about it?

Electronics:

A line-drive amplifier has a gain of 20dBs on zero level – how big a power supply would such an amp need?

Do they know that 0dBu is 0.773v? Do they know that 20dBs is approx a ten-fold increase in power? If they can do the calculation don’t let them escape!

What is the significance of technical and domestic (“cooking”) mains – why shouldn’t equipment powered by one distribution be connected to equipment powered by the other?

Do they appreciate earth distribution and the danger of putting mains hum over every feed in a facility?

Avid:

On a Unity server what is the difference between ‘Allocation Groups’ and ‘Workspaces’?

Any Unity configuring experience (or more importantly have they taken an interest in an installation they may have had to look after?)

What is a Media Database and why would you ‘trash’ it. What other things might you ‘trash’?

Have they had to provide tech support to editors?

Good to see....

...that this venerable blog is blocked in China! Thanks to Kev for alerting me to this - you can check to see if your website is considered too subversive for Chinese people to read.

Overpriced Apple stuff & unreliability

Wow - lovely bank holiday weekend but things went wrong! The battery on my MacBook died (just vanished - not seen under Vista or OS-X) - and guess what, a trip to the Apple Store revealed that it will take 'till Friday for a genius to see me (they drink the Kool Aid!) - in the meantime it's just shy of a hundred quid for a replacement battery. On the subject of the Genius Bar - How can someone in their mid-twenties be an expert in anything? Anyhow - I seemed to remember it being the same price for a replacement DC power supply. In fact, looking around I saw an Apple branded rucksack for a hundred quid, the cheapest iPod, and Joe found a set of headphones for (yes!), a ton. The Apple Store is like the Pound Store for wealthy people; ¨yes, ladies and gents, everything a hundred pounds (or multiples thereof)¨.
Also - my Belkin Skype handset stopped working and the good folks at Broadband Buyer did the usual reseller step-backwards and refused to be of any help further than giving me Belkin US's tech support number.
Then, after tidying out one of our attics and putting down a rug etc. so the kids can do Warhammer up there I fell out of the loft! I need a hot bath....

Growing up an army brat

I grew up on military bases and in embassies and there were a few things that I thought were normal - chocolate from army composite ration packs which was just a slab of dairy milk with the NATO stock number on it. One other thing was that my Dad (who'd done the MI6 photography training) would often borrow a work OM1 and snap family pictures and then they'd get processed in the embassy lab. So, here is a picture of me, on a sledge, with an MI6 reference number and the word restricted on it! Have I just broken the official secrets act?!

CSI:Pie-ami

I love Weebl & Bob and CSI does it for me as well. Watch this very funny combo.

Kumala, kumala, kumala VISTA!

After trying to carve out a half-day to repave my Macbook with Vista I eventually got the chance. So, I threw in a new 160gig drive, re-loaded Tiger and used BootCamp v1.2 (which now comes with all the Vista drivers) and installed the copy of Vista Ultimate that James Clarke sent me straight from Microsoft!
Given that I have really enjoyed using this little MacBook for the last six months - it's been the fastest PC I've ever had for work purposes - I was interested to see how well Vista would run. I haven't been disappointed - I shall review my experiences with Vista soon, but here are a few thoughts about BootCamp 1.2 as it applies to the v.1 MacBook (white, dirty-white!);

• Although BootCamp includes a proper keyboard layout it doesn't install it as default. Go to the Language Bar and install it as the primary keyboard layout.


• The mouse-pad is a load more usable - including a very neat right-click feature and two-finger scrolling (as under OS-X)


• The remote works with MediaPlayer - very good, I now need to retrieve that unused gadget from the depths of my rucksack!


• The eyesight camera works (even thought the release notes say it won't).

Unit Post and JVC monitors

This from UKPost.org

Tim Burton, Technical Manager, Unit Post Production, explains, "The MCR has enabled us to keep the edit suites cutting 100% of the time, and streamline how we execute ancillary tasks. The biggest gains have been in digital delivery and rendering times, by moving these tasks from the workstations to a 20 processor cluster we have seen a 5 fold increase in speed. Root6 completed the installation to an extremely high standard and It was a pleasure to work with Phil Crawley as he took the concept and helped develop it into a rounded solution within weeks. We have only scratched the surface of what this technology can offer and are continuing to expand and refine our systems and workflows."

I like those guy! I was back there today helping them out with some colour issues in their grading room. I discovered a few things about JVC SD/HD monitors - specifically;

• If you use one of their HD-SDi, SD, or mixed-mode cards you only get the Rec601 matrix. This means that when you calibrate for the tube for correct illuminant-D you wind up with a monitor that shifts either green or magenta (depending on which way you calibrated).


• If you install a component input card the colourimetry doesn't shift in this way - BUT the change in the raster causes the monitor to sit the picture down (the blacks get crushed) and you get a slight yellow cast in the white.

So, with all this in mind I've taken to calibrating those displays for HD and SD and handing the customer a set of instructions of changing the numbers when they start a new job.

Celebrities - just like the rest (or worst!) of us.

I was working in an edit suite recently and overheard a well known TV personality making a call to book train tickets. They wanted to go to Glasgow first class (hey, if you've got the cash why not travel in comfort?) but booking four tickets (around the same table) so that...

...I don't have to sit next to any common people

Now, this person has a column in The Independent and presents themselves as fair-minded, liberal, person-of-the-people in their writing/TV presenting!

One celeb I've got a bit of experience of is Jeremy Paxman - In the late eighties I was working as a maintenance engineer in BBC Television News and was doing the late shift one night (essentially what was the Nine O'clock News and then Newsnight) and was on the studio floor in Studio Two, BBC Television Centre trying to fix Paxman's 'cought-cut' (a button on a long cable that the newsreader keeps to hand to momentarily mute his microphone if he has a coughing fit). Not really noticing the time and my brain having long blanked out the seemingly unending re-cueing of the theme music over the studio's monitors I didn't realise that while scrabbling about under the programme desk the Studio Manager had counted the crew down for the live transmission. As I emerged from under the desk by Paxman's legs he put a gentle yet very firm hand on my head and pushed me back under the table-top and as he finished delivering his piece to camera introducing the first report on video tape he let go and said with a broad grin "you didn't know we were on the air, did you?" - what a gentleman! Not at all like the media-types I have to deal with nowadays.

Paxman anecdote no.2

One of the guys who was an engineer on my team used to do a monthly comic strip featuring the adventures of "Paxman" - a caped crusader who always won the day with his hard-questioning of politicians(!) - The strip would get photo-copied and put up on staff noticeboards around the building (the days before the web!) - eventually the weight of 'stop abusing the noticeboards' emails meant my colleague stopped the cartoon. One day a few months later another colleague had to go and fix the vt100 terminal in Paxman's office and noticed the complete set of cartoons on his pinboard.

Adrienne Electronics

Do you remember a BBC2 late-night show called Diners - back in 2002 anything that had the reality label attached to it got commissioned (although admittedly on very late in the evening). If you Google for it now there is scant evidence of it! I did find a John Walsh article from The Independent. Anyhow - one of the problems I had to solve for that show was using cheap Avids (software-only versions - ExpressDV back then) to capture or log live feeds with timecode. Of course the studio or OB sends you audio timecode (the kind that sounds like a fax and comes down a twisted pair cable) but all hardware-less edit stations assumed the timecode comes down the RS422 line as part of the machine control.
Adrienne Electronics do a range of really useful boxes to address these kind of problems - the AEC-Box-2 takes in audio code and has a 9-pin connector. It emulates a VTR but (being a solid box) doesn't actually play or rewind tape - it just tells the Avid it is doing so (in this case it's an Avid MCSoft with SDi Mojo). The really cool thing is that when the Avid asks for timecode down the RS422 the box returns what it is receiving on it's input. It's the ideal solution for using cheap workstations to log or capture proper studio or OB type material.
Now I'd been puzzling about this for ages last night (got home late from the studio where I was working) and it was only over my tea that I remembered solving the problem five years before - kinda like how everyone has forgotten Diners!

ITU Rec 601 vs Rec 709 colourspace

Every superhero knows that in transitioning from standard definition television to high def we've adopted a different matrixing function for component to/from RGB conversion. The numbers for (old-skool) Rec 601 are thus;

Y = 0.299R +0.587G +0.114B
Cb = 0.564(B-Y) + 350mV
Cr = 0.713(R-Y) + 350mV

And the new kids on the block (Rec 709);

Y = 0.213R +0.715G +0.072B
Cb = 0.539(B-Y) + 350mV
Cr = 0.635(R-Y) + 350mV

So, not only has the weighting of the colours that make up the luminance path changed but the weighting of the colour difference signals is different. I've heard varying accounts of why they felt the change was necessary - I think it's probably to do with cameras and telecines (now be entirely CCD-based as opposed to the ubiquity of tubes when 601 was being formulated) and display devices (are we going to be able to buy a tube'd monitor by the end of this year?!). The new values better reflect the tri-stimulus nature of human vision and are less bound by the very noisy response of the blue-tube in image acquisition devices of yester-year.

However, one of the upshots of this is that digital devices that can receive an SD/HD-SDi bitstream have to be able to switch in the appropriate matrix. If that isn't the case then you'd notice a green cast on pictures if you switched between standards (going from HD to SD) or a magenta error going the other way. In the case of a monitor you'd have to re-calibrate the white point to D65.

The reason this has cropped up is that a facility (where I've just started to offer them colour calibration advice) has noticed that a monitor that was lined up correctly for HD working is showing the wrong colourimetry when being sent an SD feed. It's gone green (and not with envy! - oh, and that isn't the facility in case you're wondering!). It's a JVC DTV1700 series monitor which (although a cheapie at <£2k) has an EBU-phosphored tube (so you can calibrate it to 6500k at the white point). It looks like JVC's input card doesn't do the matrix switch. So, I'm wondering what other monitors do - I was sure the Sony BVM-D range did (but those monitors started in the mid-teen thousands of pounds). Any comments from people who've hit this before? As an aside the image (right - click it!) is from a very good Tektronix poster entitled Understanding Colors and Gamut - I have many copies (along with the equally exciting Understanding High Definition Video!) - give me a yell if you want one.

Mark Russinovich: From Winternals to Microsoft

All Windows users owe Russinovich a huge debt;

• He discovered Sony's root-kit shenanigans
• He used to run SysInternals - a great resource for admins and power-users. Thankfully Microsoft have maintained it as part of TechNet.
• He's now part of the Windows Core team - watch the 55min clip on Channel 9 - I feel better about Vista already! (AND - thanks to Mr James Clarke) I'll be installing Ultimate Edition on my MacBook in the next few days.

Cerberus and FTP minucea

Having written about Cerberus FTP server in the past I did notice that after I upgraded to v 2.43 on my Windows server I was experiencing some delays when publishing from Blogger. Now I don't know about the finer points of FTP (despite it being the protocol I've used on an almost daily basis since 1985!) but a quick tweak of Cerberus's passive FTP settings made things good - see the screen-shot.
As an aside one of the other nice features of Cerberus is that it handles IP banning automatically. Whereas IIS will happily sit there letting a Chinese hacker run a password generator on you for days (it takes about three hours to fill your system even log over a cable-modem connection) Cerberus will (by default) lock out an IP address for three hours once it's got it's login wrong ten times - very cool. It means your FTP server suddenly isn't vulnerable - why has Microsoft never got wise to this kind of thing?

Zoo animals 'may jump into park'

Oh dear! According to BBC News the tigers at Regents Park Zoo could leap the fence and start roaming the surrounding area! The workshop is only a few hundred yards from the Zoo and so I'm thinking the bars I had put on the windows last year might have been a wise precaution!