Stitching 3D-180 video from a Z CAM K1-Pro
Converting 3D-180 video from a Z CAM K1-Pro is necessary before post-production work. Learn how to use Z CAM WonderStitch effectively.
Read Time: 4 Minutes
Requirements
Z CAM VR (referred to as Z CAM Controller in the product documentation)
Video files from a Z CAM K1-Pro
Introduction
The Z CAM K1-Pro is a VR video camera dedicated to capturing 3D-180 video for stereoscopic viewing within headsets. Processing the left and right video files into a format suitable for use in post-production workflows and for playing in headsets is normally done using WonderStitch, dedicated software from Z CAM. This article shows different ways of handling the files that the K1-Pro generates and explains the options that WonderStitch offers.
Stitching, really?
Stitching refers to merging two or more images or videos together to create a single larger composite end result. The process of converting clips from a 3D-180 camera such as the Z CAM K1-Pro or the Canon R5C with the Canon RF 5.2mm Dual Fisheye lens is really a process of changing the image projection from fisheye to a cropped equirectangular projection, with the output from the left lens placed beside the output from the right. Purists may debate whether this is really stitching, but this step is equivalent to the stitching process that happens with 360 media, so it’s an accepted industry term.
Copying files from the camera
Files can be copied from the camera’s memory cards in the traditional manner, but they can also be downloaded directly from the camera to a computer without removing the memory cards. This is done using the Z CAM VR software to connect to the camera either by wifi or Ethernet.
A wifi connection can be set up easily using the camera’s built-in wifi network; if a wifi symbol isn’t shown on the camera’s small LCD panel, press and hold the ‘i’ button for a few seconds to enable this feature. Wifi is a very convenient way to connect, but transferring multiple gigabytes this way is a slow process. For faster speeds use an Ethernet lead connected directly to the Ethernet port on the base of the camera.
In the Z CAM VR app, choose Tools > File Manager. (If the camera can’t be found, check that it is connected by Ethernet or by wifi, then choose Action > Scan Cameras, select your camera, and try again.) The File Manager window will show the files on the camera’s memory cards. It shows the left and right pairs of videos as one, with an option to look more closely and preview the fisheye output from each lens individually.
Click the checkmarks to the right of each video clip that is to be downloaded. If any recording is longer than five minutes it will have been split into multiple files, so make sure to check them all. Then click Download and wait for the process to complete. By default videos are stored in a Z CAM folder in the computer’s standard Movies folder, but this can be changed in the app’s preferences.
Videos downloaded by the Z CAM software will be put into folders named using part of the video file names. Z CAM WonderStitch recognizes these and concatenates the five-minute segments together when stitching. It will merge all clips it recognizes, so avoid keeping unrelated files or folders in the same location.
Manual file copying is simply a matter of using a card reader and copying the relevant video files from both SD cards. Each left-right pair of video files should be stored together in their own folders rather than with any other files. This method of getting the video files from the camera is very simple, but there is one drawback when using longer clips that the camera split across five-minute segments; WonderStitch won’t attempt to concatenate separate clips for you. (There is a way to achieve this with a bit of folder naming work; see ‘Speaking WonderStitch’s Language' below for details.)
Speaking WonderStitch’s Language
When copying videos manually, unless you name these folders correctly Z CAM WonderStitch won’t make any attempt to join long clips together. The naming convention is based on the video file names, and you can replicate this relatively simply.
File names follow a specific pattern. They begin with “ZCAM” followed by a four-digit number that identifies the shot, then an underscore, followed by a number that identifies the specific lens (0000 for the right, 0001 for the left). Then after another underscore there’s a number that represents the year, month, day and time.
Take the date and time stamp part of the name, then an underscore, then the shot identifier from the start of the name, and make that the folder name. For example, for a pair of video files named ZCAM0165_0001_202211261830.MOV and ZCAM0165_0001_202211261830.MOV their folder would be named 202211261830_0165. Put the pair of videos into the folder, then repeat with the next pair of clips. Once done, point WonderStitch to the location of these hand-named folders; it will recognize them all and offer to stitch everything together into one long video file. Note that it will do this even if the sets of videos aren’t intended to be rendered together; plan your file and folder structure accordingly.
Stitching with Z CAM WonderStitch
Once the camera’s files are copied and ready, Z CAM WonderStitch can process them into the required left-right and non-fisheye format for viewing in a headset, ready to be passed along to the post-production stage. In the left-hand pane of the WonderStitch window, choose the input directory so it can find the video files, make sure the start and end frames are set, and set the destination directory for the finished clips.
For normal 3D-180 work make sure the output resolution is 2880, the output type is VR180, and the layout is ‘LEFT_RIGHT’.
In the Basic Settings section, use h.264 as the codec; h.265 is generally not recommended for files still to go through post-production editing. The quality for 2880px resolution output defaults to 120Mbps CBR; test this before trying higher or lower quality settings. Switch Left/Right should be left on for all normal stereoscopic work, as should Smart Align.
Third-party stitching
Some prefer to use third-party stitching software such as Mistika VR rather than WonderStitch to stitch files from a K1-Pro camera. Stitching can be faster in other software and it may be a better fit for some workflows, but it is a good idea to familiarize yourself with the capabilities of dedicated OEM software before choosing to run with third-party options.
Learn about the tools, techniques, work flows and best practices required for producing and delivering immersive 180 and 360 video for VR.
