Getting started with cinemetrics

In this blog, I continue the analysis of a scene from my previous blog where I start to capture standard ‘cinemetrics’ data.

One aspect of my research is whether editing has been influenced by the use of 3D. As a starting point I need to collect data on what Barry Salt describes as the “simplest” statistic: Average Shot Length (ASL). As detailed in my previous blog, I have captured stills from each shot within a scene, catalogued them in a spreadsheet, and have rough timings for each shot.

The cover to Film Style and Technology: History and Analysis by Barry Salt.

To get precise timings, however, I need to examine the clip frame-by-frame and this requires a video editor with a good timeline function. After an exhaustive search, I settled upon DaVinci Resolve 12.5 fromBlackmagicdesign. The free version works well for my purposes – indeed the only feature which would have been useful and is missing is the ability to grab stills directly from the Edit workspace.

The Edit workspace in DaVinci Resolve 12.5.

I worked through each shot in my catalogue to identify the precise timecode at which the shot begins. From my rough timings I know that, for example, the second shot begins around 15s. I used this as a guide to identify the thumbnail on DaVinci Resolve’s timeline where the shot changes, before using the left and right arrows on the keyboard to find the precise timecode. This process reveals the second shot began at 14:11 (i.e. 14s and 11 frames).

Each timecode was then recorded in the catalogue against each shot. This is a painstaking process, but one that is aided by having a list of shots with rough timings to work through. It is otherwise easy to miss a change of shot or to lose one’s place. I converted each timecode into a frame number (on the basis that my clip is running at 24fps). Knowing the frame number at which each shot began, I could use a simple spreadsheet formula to calculate the duration of each shot. For example, with the second shot:

Start of Second Shot: 14:11 (i.e. frame number 347).Start of Third Shot: 17:09 (i.e. frame number 417).Duration of Second Shot = 417 – 347 = 70 frames = 2.9s.

In my next blog, I will discuss how I went about extending the ‘cinemetrics’ data with depth data.