Convert AVCHD video using Quicktime Player (MacOS 10.8 or later)

Quicktime Player in Mac OS 10.8, 10.9 or 10.10 (Mountain Lion or later) will open and export AVCHD files in the Quicktime .mov format at various resolutions. 

1. You can drag the file over the Quicktime Player icon, or right click (CTRL + Click) on a file and select Open With > Quicktime Player
2. Once the file is open in QT, go to File > Export >  and select a resolution
3. You’ll get an export dialog where you can name and choose where to save your .mov
4. An Apple forum ( indicates Quicktime can have issues opening the files if they aren't in all caps.  You can inspect the files by right clicking (or control + click) on the file  and selecting Show Package Contents. 
5. If your files aren’t in all caps, you can carefully rename using all caps (but don’t change the actual names).