Stereo3D Virtual Floating Windows

Introduction

Virtual Floating Windows (VFW) is a fairly recent and strong stereoscopic tool used in the postproduction process. Keeping a 3D scene within constraints the screen plane to preserve and maintain the viewing window can be a very difficult and a limiting task. If stereoscopic window violations are not addressed then they will disrupt the viewer’s 3D viewing experience. By “floating the window”, the screen plane can be shaped and formed, pushed and pulled in and out of 3D space in every direction.

Virtual Floating Windows are achieved adding black masks on the sides of the either the left or right images. Masking the sides changes the apparent depth position of the screen but does not affect the distance and depth placement of objects within the scene. Virtual Floating Windows are a great way to mask stereoscopic window violations, when a subject enters the scene in negative parallax (off the screen, towards the audience). By bringing the perceived location of the screen in front of subject, the violation no longer occurs, as it is acceptable to enter a scene from behind the window, in positive parallax.

By masking the right image on the right side, the right edge of the screen will be perceived to move forward towards the audience where as masking the left side of the left image will move the left edge of the screen towards the audience. Masking both of these at the same time will move the entire screen plane forward. Masking the opposite edges, the right side of the left image and the left side of the right image will push the screen back away from the audience. By pulling the top or bottom corners so that the mask is slanted will make the screen plane seem as though it is being tilted forward.

The floating window should always be a few pixels wider then the interaxial distance of the subject in the scene that is causing the violation. This way the window will have some breathing room between the apparent edge and the subject.

Initial Setup

The Virtual Floating Windows plug-in, as with all the plug-ins in the Stereo3D suite, can be applied to an already pre-existing multiplexed stereo pair (left & right video files married together) that is any number of 3D formats (side-by-side, over-under, etc) as well as be applied to a single left or right eye file and then be coupled with the correct adjacent left or right video clip.

To access the Virtual Floating Windows plug-in go to:

Video Filters à Dashwood Stereo3D Toolbox à Stereo3D Virtual Floating Windows

Once applied to the clip, the clips render status will appear red in the FCP timeline unless set to Unlimited-RT. To access the menu to change the timeline’s render settings click on the RT button on the far left of the timeline. Select Unlimited-RT and the clips render status will turn orange, indicating that Final Cut Pro will process as much of the un-rendered effect in real-time as permitted by the video card. Typically the more VRAM that FCP has access to, the closer to real-time it will display the un-rendered clip. If an external 3D Monitor is being used for playback, then Playback Video Quality should be set to High and Playback Frame Rate can be left at Dynamic.

Using Virtual Floating Windows

Preview On

Depending the S3D output mode being used, it’s not always easy to see the physical masks being created by the virtual floating windows in 2D. By using the Preview On in the Virtual Floating Window (VFW) user interface, it is much simpler to see the masks regardless of the S3D output.

Left Floating Window

Top Left –Pulls the top left corner of the screen edge towards the audience.

Bottom Left –Pulls the bottom left corner of the screen edge towards the audience.

Top Right –Pushes the top right of the screen plane away from the audience.

Bottom Right –Pushes the bottom right of the screen plane away from the audience.

Horizontal Edge Softness –Feathers and softens the edge of the VFW masks on the side of the screen.

Soft Mask Top –Tips the top of the screen forward.

Soft Mask Bottom –Slants the bottom of the screen forward

Right Floating Window

Top Left –Pushes the top left of the screen plane away from the audience.

Bottom Left –Pushes the bottom left of the screen plane away from the audience.

Top Right –Pulls the top right corner of the screen edge towards the audience.

Bottom Right –Pulls the bottom right corner of the screen edge towards the audience.

Horizontal Edge Softness –Feathers and softens the edge of the VFW masks on the side of the screen.

Soft Mask Top –Tips the top of the screen forward.

Soft Mask Bottom –Slants the bottom of the screen forward

Each value of 1 equates to 1 pixel of distance. Animating and keyframing the VFW is acceptable and very common practice. A VFW can be keyframed so that it moves into position to cover up any stereoscopic window violations and then move back.

Virtual Floating Windows Input Options

S3D Input

Please refer to either Clip Coupler or Geometry Plug-in manuals for details on how to use the S3D Input and for brief definitions of the various 3D formats.

Click the links below.

http://www.dashwood3d.com/help/stereo3d-clip-coupler/

http://www.dashwood3d.com/help/stereo3d-geometry/

Input Squeezed (Only available when using Side-by-Side input types)

This option tells Stereo3D Toolbox whether or not the side-by-side footage is squeezed into one full resolution composition or if it is two full resolution compositions coupled in the same file.

Swap Inputs

The naming hierarchy of left & right 3D files can sometimes be incorrect depending on the accuracy of the Data Management Technologist’s file handling and the labeling of the physical cameras on a Beam-Splitter Rig. This naming error will be evident if the footage is viewed on a 3D display, as the background will be perceived to be floating in front of objects that should be in the foreground and vice-versa. When incorrectly labeled the left and right eye video will be reversed and thus the human eye will be receiving incorrect information. If the viewer is unsure if the footage is named properly, then by clicking Swap Input back and forth while playing the footage, the 3D will either be comfortable to watch or slightly straining to view. If the footage is comfortable to watch and the objects within the scene are positioned in the proper location in 3D space (foreground objects appearing at the front or “popping” off the screen & background objects appearing in the back or “behind” the screen) when Swap Input is selected, then this indicates that the footage has been named incorrectly.

Global Output Mode

Global Output Mode is a keen way to set and apply the same stereoscopic output mode to an entire sequence so that every clip does not have to be adjusted individually. Selecting the Use Global Output Mode check box on a specific clip ensures that that clip will adhere to whatever the current Global Output Mode is set to. To set the global output mode, select the appropriate output using the Global S3D Output Mode drop down menu, which only becomes available when Use Global Output Mode has been selected, then click the Set Global Output Mode icon.

This setting is particularly useful when a sequence needs to be edited using a viewing method such as Anaglyph and then exported out to a stereoscopic standard such as side-by-side or over-under. Ensuring that every clip in the timeline has the Use Global Output Mode checkbox selected will certify that the entire timeline will output to the correct format.

S3D Output Options

The various stereoscopic 3D output modes available in Stereo3D Toolbox can be accessed underneath the S3D Output Mode Tab. Side-by-side, Line by Line Interlaced and Above Below are the three output modes are most commonly found finishing formats besides exporting separate left and right video tracks or upgrading to a DCP for a cinema release.

These formats are discussed in the Clip Coupler & Geometry Guides.

Swap Outputs

It is sometimes necessary to swap the output as some 3D Monitors interleave their polarized signals differently, amongst other reasons. If ever needed, the Swap Outputs checkbox can be selected after the convergence and stereoscopic settings have been changed.

Flip Flop

Cameras shot on certain beam splitter rigs need one or both of the cameras to be flipped or flopped in order for the perspectives to match.

Flip will rotate the image 180º so that it is upside down from it’s native position.

Flop will change the images perspective so that is a mirror image of it’s native position as though it has been rotated 180º along the z-axis.