I got the "Mixed Format Media Warning". Thanks for introducing this warning and to make clear, that not all video files are in the best format. Unfortunately, I always struggle to find the best codec and container for video files on Windows.
It would be nice to have an option, so that Isadora automatically converts the video files in the best format for using the files in Isadora. It would be ok when I have to say Isadora, which files I just want to play forward with normal speed and which files I want to do special things like playing backward and so on.
Since Isadora is able to read all these files and do the uncompressing and decoding in real time, it is maybe also possible to let Isadora convert and save the files to an optimal codec and container beforehand. With the optimal file format for Isadora, much performance can be gained.