I shoot video in the AVCHD format, with resulting .MTS files. To deal with these files, I use Media Converter, which is free and offers lossless quality, meaning no quality loss. All this software does is re-wrap the file to a file that your video editing or video player software recognizes, which for me is a .MOV file. When you open Media Converter, go to Preferences>Presets, and click the More Presets button at the bottom of the window. A web page will open with additional presets. Choose Re-wrap AVCHD for Quicktime - uncompressed Audio by clicking on the icon to the right of the description, which will download the preset. Then double click the downloaded file to add it to Media Converters Presets. The other software I use as part of my workflow is MPlayerX, which is also free. Drag this App to your Dock. Now your ready to work. I drill down to the AVCHD Video .MTS files, click on the first file and drag it onto the MPlayerX icon in the Dock, which will play the video clip so I know what video clip I’m looking at. The playback will be a little jerky and the audio will be out of sync, but do not worry, as this is only a reference for you to use to see what the chosen video clip is about. After you go through all your video clips, deleting the unwanted ones, and writing a description for the keepers (by clicking on the video clips name and changing it), click on any one file once, then in your Menu Bar go to File>Get Info. A window will open, go down to Open With, and in the Pull Down Menu, navigate to the Media Converter App in your Applications Folder, and then click on the Change All button below. What you just did was tell your computer that any time you double click a .MTS file, Media Converter will be the default App that will open it with a Dialog Window for you to navigate to where the resulting .MOV video files will be saved. Once saved, just double click a file, which should open in QuickTime, or you will be able to be import the video files into your video editing software, like Final Cut Pro or Express.