The thing is this does not happen all the time. But it does happen on both version 5 and version 6 of Tracker. The thing is I haven't seen it prior to this semester.

The video operates normally as long as we don't try to trim it. After trimming, what it looks like it is doing is after each valid data point, backing up two frames and then going forward three frames until we get to the next valid point.

There's also an issue with opening what appear to be valid .mov video files, but that happens way less often so I haven't investigated it very thoroughly. Out of a summer class of 7, one has gotten a "cannot load" error. It could be a corrupt file. VLC player will still play a lot of corrupt files. There were three other videos in her group so we just did without that one rather than waste class time debugging.

All seven have had the stuttering problem at one time or another. For one person, it went away with a reboot of the computer. In most cases, we have had to import the data into Excel and delete the invalid points. It is tedious to analyze in Excel since I can't get it to do a trendline for part of a graph like we can in Tracker with a curve fit.

This does not happen with every video. Some stutter, some don't. I tried to attach an example of a stuttering video but it is > 2MB.