When your computer is installed with Mac OS X with iMovie, you can play .mov files with Apple Intermediate codec (AIC), which is designed by Apple, Inc. Even though AIC is not technically the uncompressed video codec, it works similarly to uncompressed video in iMovie as it will be natively supported by iMovie.
While editing with uncompressed videos or .mov with AIC, you can enjoy the highest video quality. If you are looking for uncompressed .mov as output codec for conversion from MTS to MOV, Aunsoft MTS/M2TS Converter for Mac is one of the only programs on Mac to open .mts and .m2ts files and convert them easily. The Mac AVCHD to AIC converter provides Apple built-in codec with .mov as file extension.
Since all Mac OS X software support QuickTime codec, Final Cut Studio, Final Cut Pro, Final Cut Express, iMovie can use Apple Intermediate codec. Here I would like to take the AVCHD files from Sony HDR-CX550 as an example, and convert MTS to AIC for iMovie.
Step 1. Transfer Sony videos to Aunsoft MTS/M2TS Converter for Mac.
Connect Sony HDR-CX550 to iMac, copy and transfer the .mts files from camcorder to Apple hard drive. You can also run Aunsoft MTS/M2TS Converter for Mac as the best AVCHD to MOV with apple built-in codec converter on Mac, and click the "Add" button to download .mts files from camcorder to the application.
Step 2. Choose AIC codec for Mac.
Click the "Format" option, and move mouse cursor to QuickTime Movie Format > Apple InterMediate Codec(AIC) (*.mov) as output format. The Mac MTS/M2TS to AIC converter will rewrap and transcode AVCHD files to MOV with the high quality apple built-in codec.
Step 3. Set 1920x1080 video size.
Click the "Settings" button and find the output video size option. Choose 1920*1080 as output video size to keep original 16:9 video.
Step 4. Convert Sony CX550 MTS to MOV with AIC for iMovie and FCE.
Click the convert button under the preview window, the Mac AVCHD to MOV with apple built-in codec converter will start converting Sony CX550 AVCHD MTS/M2TS to MOV with AIC like uncompressed video for iMovie, FCE, FCP.
After the conversion, just import the 1920x1080 videos to iMovie/FCE/FCP for editing in high quality as the alternative to uncompressed videos.
If you missed the AIC codec or the output video does not include video, you may need to download and install Apple Intermediate codec from Apple official site.