Virtual Reality Streaming Tools and Workflow, Part 2: Production Workflow

Calibrating the Inputs

In the first article, I related that Mobeon president Mark Alamares, who supplied all the gear and support that made this project happen, was a bit concerned about how easily I could master the workflow. One big part of his concern was this step, where you calibrate the inputs. During this process, the software figures out which cameras are pointing which way and stitches them together.

When Mobeon demonstrated the system and workflow to me it Streaming Media West, it took several tries to make this process happen. That's because the system needs a certain number of well-defined control points to aid the process. If one camera is pointing to a blank wall, or the ceiling is flat white, the software can’t find the control points to perform the stitch, and advises you to try again.

To help the software find these control points, you tilt the tripod in different directions while pressing the calibration button and hoping for the best. At Streaming Media West, it took seven or eight tries to make it happen, and Alamares and the Mobeon tech who helped me through the process related that it often took many more tries than that. In my office, however, the software found the calibration on the first try, turning this process into a non-issue.

To get started, you click the calibration button on the upper right of Figure 5 (below).

Figure 5. Starting the calibration process.

The Configuration calibration screen shown in Figure 6 (below) appears. These entries are camera-specific, and these are the settings for the GoPro rig that I used. I was fortunate that these were somehow already programmed into the system, because I couldn't find any documentation telling me which settings to use.

Figure 6. Configuring the calibration settings.

This is probably as good a time as any to comment that no one would call the Vahana software overly documented. Beyond one or two YouTube videos, you're pretty much on your own. In fact, on the VideoStitch website, if you click Vahana VR User Guide, you’re taken directly to this YouTube video. In most instances, that's okay. However, if you're using a different camera rig, I'm not sure where to point you to find the appropriate settings for that rig.

Once you click OK in the Configuration Calibration window, the software either finds a good stitch or displays an error message to try again. What’s shown in Figure 7 (below) is actually a good stitch; it just needs a little help.

Figure 7. The software performed the stitch. Click the image to see it at full size.

Click the Orientation icon in the toolbar on the right, and drag the stitch around until the black bar is on the bottom, which is easier than it looks (Figure 8, below). While you can click the Grid icon to display a grid over the image, I didn't find it that helpful. I did find the exposure controls helpful in brightening the top of the image, though I don't have a screen that shows that.

Figure 8. Using the orientation control to finalize the stitch. Click the image to see it at full size.

Note that once you find a configuration that calibrates correctly, that configuration should continue to work without recalibration until you switch some of the camera inputs, or change to a different rig. If you're careful, you should be able to use the same calibrated configuration for multiple shoots. In my case, I calibrated in my office, and then carried the computer and connected camera a few blocks to the school without disconnecting any cameras. Otherwise, if you carefully match the HDMI inputs from the cameras to the slots on the input card, you should be able to accomplish the same thing.