Our eyes perceive brightness differently than an electronic sensor does. Video monitors are locked into a standard for color and contrast, but now Digital Cinema camera systems are being used to capture images that are used and displayed in media that can see well beyond those limitations. Brightness is captured on a Linear scale (LIN), and usually stored with video gamma (REC709) or with a more film-like Logarithmic encoding (LOG). What does this mean, how does one use it, and what capabilities does it represent?

In the first of a series of Technical Resource articles and CineTechnica posts, I present an introduction to the concept of LOG, its origins and capabilities. Click here for the article.

This has been out for a while, but it doesn’t seem to have been widely circulated. Sony has a white paper on S-Log which describes the intended use of S-Log gamma, from production to post. Of particular interest to compositors and colorists are the formulas for translating between S-Log and Linear Light.

Download the S-Log White Paper here.

The recent v.675 release of the Phantom software from Vision Research modifies how the white balance is stored in the raw cine files. This rendered the files created with this version incompatible with all the existing third party products that read the Phantom files.

Fortunately, developers have been quick to update their tools. Version 2.0.12 of the GlueTools Phantom Cine toolkit now supports the new white balance system, and I just got word that Iridas has implemented support as well, and that updated builds of their products should be available soon.

So, if you’ve downloaded files with the latest Phantom software and you see images that look like this:

instead of this:

you know you need to update your post software.

Canon has announced the 1D Mark IV, a 16 megapixel, APS-H sensor camera (vs. APS-C in the 7D and full frame in the 5D Mk II) capable of shooting 1080P video at 24, 25 or 30 fps, as well as 720P at 50 or 60 fps. It’s got some pretty nice still specs as well, of course. As usual, Vincent Laforet has made a short movie with it already, Nocturne. Can a full frame 1Ds Mark IV be far behind?

In other news, the word on the street is that Canon will be releasing a firmware update in 2010 adding 24P and 25P video capabilities to the 5D Mark II. Good news for early adopters.

There is a bug that pops up from time to time preventing Final Cut from recognizing Phantom cine files even when the GlueTools Phantom Toolkit is properly installed. There is a fix detailed on the GlueTools forum, but it requires familiarity with the Unix command line. To simplify the application of the fix, I’ve created an Applescript that automates this command – just download the program, and drag the cine files you need to fix onto the icon.

Note that this program only works in Leopard. Also, it currently will not look into a folder that you drop onto it — you’ll need to go into the folder and select the cine files (you can use command-A) and drag and drop them.

Get the file here: fix_cines.app

DVCPRO HD vs. AVC-Intra

In my last entry, I discussed the 3-way trade off between quality, size and complexity in codecs. Panasonic’s move from DVCPRO HD to AVC-Intra in their latest generation of P2 cameras provides an excellent example of a trade off between quality and complexity, as both codecs record at the same bit rate of 100mb/sec (at 30fps). How much better is AVC-Intra? To start off with, it preserves a lot more image information than DVCPRO HD. It records full raster (1920×1080, when recording 1080p) 4:2:2 at 10 bits per channel compared to 1280×1080 4:2:2 at 8 bits per channel, which means it’s starting out with almost double the data. Here’s a comparison of a frame of each (the same difference frames we looked at last time).

…continue reading Image Evaluation Series: Compression (Pt. 2)

For pretty much any film or video project you might work on these days, you’ll spend at least part of the time dealing with compressed material. In order to decide which codec to use, you need to keep in mind what purpose you are using it for and how a particular codec fulfills that purpose. In this entry, I’ll explain some of the techniques I use for evaluating codecs. In later entries I’ll cover some more specific results.

…continue reading Image Evaluation Series: Compression (Pt. 1)