In general, you can move an Isadora patch from a Macintosh to Windows and it will work the same on both platforms. However, you may encounter issues issues with media playback.
Moving from macOS to Windows
On macOS, we use the most recent system from Apple to play movies, called AVFoundation. If you move your macOS media (i.e., .mov files) to Windows, they will be played by the much older QuickTime for Windows, which is not nearly as efficient as AVFoundation. If you have a very heavy patch, with multiple channels of video playing simultaneously, it may show a noticeable degradation in performance under Windows.
Our current recommendation when moving from macOS to Windows is to recompress your movie files into AVI containers using the Renderheads HAP for Directshow Codec (which you can get here for free). If you install this codec, you can easily export your movies files to HAP in Adobe Premiere, Vegas and other professional video apps. HAP is extremely efficient under Windows, especially if you have a top-notch graphics card – you may get even better performance with HAP than you got on macOS. HAP files are large, so you will need plenty of disk space and an SSD hard drive for optimum performance.
If you don't want to use HAP, you can use another Windows native container like AVI or WMV. When you use these containers, Isadora uses the Windows native system to play them, ensuring the best possible efficiency.
Moving from Windows to macOS
If you're going from Windows to Mac, and you're using AVI or WMV files, then you'll definitely need to re-encode your movies because the macOS version of Isadora can't play those formats. If you're using QuickTime files under Windows, it is likely you'll get better performance on macOS for the reasons outlined above.
The Proof is in the Pudding: Test on the Target Machine!
Regardless, we strongly recommend that you test your patch under Windows thoroughly. Mac OS and Windows are simply two different beasts, and the only way to be sure everything runs perfectly is to go through the entire file on the target machine. By taking the time to do this, you'll ensure you won't be surprised by something unexpected at the wrong moment.