How much does VidSync cost?
VidSync itself is free. But using it requires video cameras, a Mac computer, and some inexpensive calibration hardware (see below).
Is there a Windows version?
Unfortunately not. VidSync's code relies on dozens of Mac-specific technologies, some of which don't have Windows equivalents. Creating a Windows or cross-platform version would be a years-long project, rewriting the entire program from the ground up, and it would still probably be missing some important features.
However, before dismissing VidSync for lack of a Mac, consider that the only Windows software offering similar functionality to VidSync has fewer features and costs more money than buying a new Mac on which to run VidSync for free.
What hardware is required to use VidSync?
It depends on your project. To do a full 3-D analysis, you need at least two video cameras, supplies to mount them together, and a couple calibration objects that can be easily built for less than $200 USD.
You can also do 2-D measurements, with more limited calibration needs, with one or more video cameras. You can also use VidSync as an event logger and annotater with any number of video cameras, without any calibration.
A small LED flashlight, flicked on and off in front of the cameras one time at the start of the videos, is helpful for synchronization.
Does VidSync only work with underwater video?
No, it can work in terrestrial environments as well. The currently showcased projects and examples are from underwater because VidSync was originally developed for fisheries research, but it can be used without modification elsewhere.
The only caveat is that the size of the calibration frame should probably be roughly within a factor of ten (or so) of the size of the area being measured. This means it could work well for studying birds in a nest or monkeys in a tree, but not for measuring distant skyscrapers or tracking airplanes through the sky. These large scales are never a problem for aquatic uses because visibility underwater is limited to regions VidSync can handle; in fact, it has been used successfully to study the largest fish in the world, whale sharks.
Is VidSync compatible with more than two cameras?
Yes. Every function including 3-D measurement works with three or more synchronized cameras if needed, but most people only need two.
Does VidSync do automatic object tracking?
Not yet. Automatic tracking was not necessary or practical for the type of in situ behavioral study for which VidSync was originally developed, in which complicated visual backdrops and the changing positions of multiple fish would quickly stymie a computer vision algorithm.
However, some projects could benefit from the realistic use of current object tracking technology. VidSync would be amenable to the addition of this feature, because it already incorporates the OpenCV library (version 2.3.1) for computer vision. That library contains code for object tracking capabilities, but right now VidSync only uses it for automatic detection of chessboard corners with its cvFindGoodFeaturesToTrack function. This is just scratching the surface of what OpenCV could do in VidSync if the need arose and someone had time to code new features.