VidSync 1.5 is a major upgrade. It's faster, more stable, and better-looking, and it adds some useful new controls. The underlying math, import/export formats, and general processes for doing things are the same, although a few buttons have moved around. The new version is backward-compatible with previously saved VidSync Document (.vsd) and auxiliary files.

The new version requires Mac OS X 10.9 (Mavericks) or later. Mavericks is a free upgrade and highly recommended. However, users restricted to older, 32-bit Macs can still download the old version of VidSync compatible with OS X 10.6 (Snow Leopard).

Major features:

• The video playback controls have been revamped. Unsynchronized videos are controlled like any other video in Apple's Quicktime Player. When two or more videos are synchronized, a new control bar opens up with more intuitive and easy-to-read buttons for all the advanced playback contols from the old version and a few new ones.
• You can now snap "portraits" of objects and view them later within VidSync, either individually or as a list of portraits of all the objects in the project. For example, I save portraits of the juvenile Chinook salmon I'm analyzing, and when a fish swims off-screen and comes back I check its parr markings against its portrait to make sure it's the same fish.
• VidSync can now be used for 2-D measurements, using a single grid of points for calibration. These will naturally be less accurate than 3-D measurements from multiple cameras, but Vidsync lets you make them as good as they can get by tapping into the same distortion correction and linear transformation algorithms used for its 3-D measurements.

Major behind-the-scenes changes:

• VidSync now uses Objective-C automatic reference counting (ARC) for memory management, which greatly reduces the potential for program crashes. This huge change to the code is only visible to users as improved stability and performance.
• VidSync now uses AVFoundation instead of QTKit to handle video playback, image capture, and exporting. (In other words, it has moved from using outdated Quicktime 7 to modern Quicktime X behind-the-scenes.) This fixes several bugs with exporting, and makes videos start/stop and play more smoothly. However, some old video files are no longer compatible with VidSync without a conversion. The rule remains that VidSync can play any file Quicktime Player can play on the same computer, but Quicktime became much more picky about video codecs in Mavericks. If your files don't work with VidSync anymore, you can convert them to a modern codec (.mov and .mp4 files using the H264 codec work well) using either Quicktime Player or a batch video converter such as Wondershare or Final Cut Compressor.

Minor features:

• The visual markers for video overlays all have very subtle, non-offset drop shadows now. These make it much easier to see light-colored text and markers against light parts of a video. 
• You can copy an annotation from one video onto all the others using the new "Mirror Selected Annotation" button.
• Advanced step controls allow choice of units, stepping by frames, minutes, or seconds.
• There are shortcut keys for play-while-pressed at the regular rate and both advanced playback rates.
• The program uses the masterclip's native timescale for all timecodes recorded. It used to sometimes switch to strange intermediate numbers.
• There are now more warnings/verifications to make it harder to accidentally mis-click and delete something you don't want to.
• Video overlays and the master time display now update live while the play-while-pressed buttons are in use.
• You can now optionally seed the automatic plumbline detection algorithm with the first two starting points it needs, which makes it easier to find good settings to read your grid.

There are hundreds of other small improvements and bug fixes.