Post Production

Inputs & Outputs of the Geometry Workflow

The primary inputs to the geometry workflow are:

  • Imagery
  • Metadata
  • Geometry Review Reports
The primary outputs from the geometry workflow are:
  • Geometry Workflow Masters
  • Geometry Decision Lists

Dailies/Footage

Dailies consist of imagery and metadata from production. This is relevant if you are in postproduction while production (principal photography) is still happening or if you are doing on-set dailies (or both!). If production has already concluded then your imagery and metadata are considered “footage.” As in 2D post, 3D footage is stored as discrete or muxed sequential files or streams of video on various digital media. Feedback from geometry reviews can help correct geometry issues on-set, freeing your team up for other responsibilities. In addition to more traditional work in the post suites, you and your team may find yourself responsible for processing on-set dailies. The idea behind on-set dailies is that your post (or a portion of your post) occurs during production and can address aspects of any of the workflows.

On-Set Dailies

If you are working on a show while production is still in progress, feedback from geometry reviews can be extremely helpful to production. This is because they may be able to correct a production issue on-set that will preserve post resources for other work. In addition to more traditional work in the post suites, you and your team may find yourself responsible for processing on-set dailies. The idea behind on-set dailies is that your post (or a portion of your post) occurs during production, as opposed to following production. With 3D on-set dailies, teams can address aspects of any of the workflows.

Workflow Masters

Workflow masters are imagery and metadata from 3D workflows (i.e., depth, color, editorial). Workflow masters reflect decisions made in other workflows. For example, say that you have made depth or color changes in a shot. That change is reflected in the depth and color workflow masters. The team must make sure that it preserves depth and color decisions as it fixes geometry issues, or make sure the shots go back to depth and color following geometry work.

Geometry Review Reports

A Geometry Review Report is a document reflecting current prioritized list of geometry issues where they occur in the show, and recommendations or guidance on how to resolve the issue. Other than shots planned for conversion and/or visual effects work, the geometry workload can be confirmed only when the team has reviewed the first set of dailies/footage in a geometry review. Unlike the depth workflow, there is no “geometry script” because geometry is primarily a corrective workflow. Ideally your show will only require minimal geometry work on a handful of short-duration shots. Some geometry issues can be resolved quickly. Other geometry issues can consume resources intended for creative work.

Geometry Decision Lists

In this book, we use the term Geometry Decision List or “GDL” to describe the document containing descriptions of the geometry corrections made to footage as recommended in the Geometry Review Report. These documents should be as complex and as complete as they need to be for your show. Teams use GDLs along with decision lists from other workflows to integrate geometry fixes into the show master. Metadata (e.g., in the form of notes, file header data) reflecting geometry corrections made to imagery must travel with the imagery so that, if necessary, geometry settings can be revisited or reverted back to previous versions.

Artifacts

Artifacts are defined as perceptible issue in imagery that cannot be otherwise identified or explained. Artifacts occur in 2D as well as 3D. An artifact is only an issue if it affects comfort and continuity. Examples of artifacts include:

  • Blurring
  • Pixel Hits
  • Video Noise
  • Color shifting
  • Color banding
  • Inconsistent flares/reflections
  • Sudden changes in depth, geometry or color
  • Otherwise unexplainable visual phenomenon

As with all other issues, artifacts are only an issue if your team determines that they fail to meet the criteria for good 3D. It is not unusual, for example, to have a single shot containing:

  • known (correctable) geometry issues like keystoning and vertical misalignment
  • known (correctable) color issues such as mismatched lens flares, mirror color wedges and polarization differences
  • known (gradable) depth issues such as excessive negative parallax
  • unidentifiable/unexplainable issues (artifacts)

As with all other issues, artifacts are only an issue if your team determines that they fail to meet the criteria for Good 3D.

Excerpt from 3d Postproduction: Stereoscopic Workflows and Techniques by Rick Baumgartner © 2014 Taylor and Francis Group. All Rights Reserved.

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