Friday, December 30, 2005
Tuesday, December 20, 2005
If you want to see our family Christmas newsletter see here.
Oh, the link above is to the Podsafe For Peace record which has a great back-story (courtesy of the Daily Source Code - see the link in the Podcast section, right). The song is cheesy as a big omelet but I love it!
Monday, December 19, 2005
An important aspect of the production/post-production chain is maintaining correct colourimetry. If the director of photography or the lighting-cameraman want that certain shade of red to be correctly delivered to the viewer then attention needs to be paid to the correct representation from the camera (be it standard or high definition or even film) through all transfer operations (potentially going between resolutions, YUV/RGB colour spaces and bit depths) to the final display surface (be it a CRT, LCD or even cinema screen). In truth colour-space management for film is a complex issue best handled by specialists like Filmlight (who are represented in the UK by Root6) and is perhaps beyond the scope of some technical notes in a newsletter! That said there are many points worth making if you are acquiring or delivering for high definition television and worried about going between colour spaces.
The CIE Chromaticity diagram (first published in 1931!) shows the gamut of human vision – essentially any display surface is a subset of this diagram and will be a triangle with red, green and blue apexes and white (actually monochrome – as the luminance of the image is reduced it tends through grey to black) in the centre. In the case of “illuminant D” (AKA “D6500” or “EBU phosphors”) – the standard definition colour standard used since the sixties in Europe we enjoy a slightly wider red range than our colonial cousins but every gamut (television, film or print) is a poor compromise on what your eyes can handle. This is where the problem begins – you have a very critical instrument at your disposal to see these differences.
Part of the problem is that all of our machines acquire images in the RGB space (TV cameras, Telecines, graphics workstations etc.) but for the most part we post-produce in a YUV space (with the exception of Sony’s new HDCam SR format, an RGB high-definition VTR) which represents an immediate lowering of the colour space. This has been the case for a long time and is well understood. Manufacturers have agreed a common “matrix” for transcoding. To make the luminance portion of the component signal the following is used:
y = 0.299 * r + 0.587 * g + 0.114 * b
Well, this is the case for standard definition (AKA “601”), but for high-def (AKA “709”):
y = 0.213 * r + 0.715 * g + 0.072 * b
Which, even if you’re not so into the maths, will give different values for the luminance (the overall level and hence look of the picture). This makes it doubly important that you get your cameraman to record some colour bars at the head of each rushes tape and that your editor checks alignment on his scope before he starts adding captions etc. The best of breed digital picture instruments are from Tektronics who Root6 are pleased to represent.
If you find you have a colour space issue (particularly going between standard and high definition formats) then the Belle Nuit Montage test chart is a good starting point. It can highlight all the common transcoding errors – be it the limited 8-bit range of old D1 videotape to some of the sub-sampling issues associated with HDCam. You can download the file at various resolutions from their website and by injecting it at the start of your workflow any inadequacies are quickly revealed and can be corrected.
Friday, December 16, 2005
Stephan & Emanuelle from Post Logic, Chia from DVS (our trainer), myself and Ben (Root6) who enjoyed the fact that we got to hire a 5-series BMW!
We also got taken through the hardware of the Clipster from a maintenance point of view and spent the last day doing SAN configuration. Their SAN is based around ADIC's StoreNext file system and as such allows you to have clients using all the common OSes - Windows, Linux, Unix (variants as well as IRIX for SG) as well as OS-X Tiger. They use X24 raidheads to control the array and so the system is not burdened with RAID operations (unlike a Unity).
Wednesday, December 07, 2005
Anyhow - I thought an application for this (other than making Stan Laurell look unwell!) would be to give a new look to digital images that you'd previously made monochrome.
Tuesday, December 06, 2005
...numerous awards for their work in commercials, short-form and broadcast programming, and their creativity is reflected in the company's impressive client base. No matter how complex your post production problem, you can be sure it will be....blah blah blahYou get the pictures.
Anyhow - The Suite (in Newman Street) have a really cute engineering page - just a bunch of pictures captured from the CCTV and looped in high speed - I was entranced - you see a guy fixing a VTR, them someone drinking tea, then someone installing something on a PC - it's great!
Monday, December 05, 2005
Saturday, December 03, 2005
I installed a new v7 Protools on Friday - wrong (set for -14dBfs), Avid still ship set for -20dBfs and countless other bits of kit come in at -24dBfs. Perhaps these people just don't understand (or can't be bothered!).
Friday, December 02, 2005
Anyhow - back to the Leitch - I could get the video level control panel to talk to the chasis and route but every time I attached an audio panel it wouldn't route both sides of the stereo pair - in the end I set the audio panel to issue commands on all levels bar the video and that did the trick. It's a bit of a bodge but works - until they try and attach an RS422 level (and then I'll get the call - probably at night!). I'm thankful I paid attention to the ESAM protocol when I was building Oasis's machine room - once you have a feel for how that works you can pretty much understand how any modern router's control system operates.
Back to inheriting old gear - monitors are the worst because the client expects them to look as good as the rest of the install - even with soft ten-year-old tubes they think the new setup will bring life back to those displays that should either be re-tubed or retired! A job we did earlier this year was a good example - the client had origional series 16x9 PVMs - even when new they weren't colour accurate but ten years down the track - well. Suffice to say Sony no longer make the SDi input board for that monitor and so we had to feed them analogue component (which in most instances is my prefered method - the analogue output of an Adrenaline BOB, for example, is a better picture than the 8-bit conversion done in the monitor input card) but the YUV was from a Decklink card! I'll stop now before my blood boils!