To get iMovie working with AVCHD .mts files perfectly, the most efficient way till now is to convert MTS to AIC MOV, something ensuring best results when using .mts files in iMovie. Learn how to.
Below I will take the 3rd party software - Brorsoft MTS/M2TS Converter for Mac to show you how to transcode MTS to AIC MOV in details. Overall, the program is an easy-to-use yet professional app which can be used a MTS to iMovie Converter under OS X Mountain Lion (10.8), Mavericks (10.9), Yosemite(10.10). It is capable of converting AVCHD MTS videos to iMovie favorable format AIC on Mac easily with the preset profile for iMovie/FCE. Besides, this Mac AVCHD converter is also available for you to convert AVCHD/AVCHD Lite to ProRes for FCP, DNxHD for Avid Media Composer, MPEG-2 for Adobe Premiere Pro. No learn the detailed guide for helping you to make your MTS recordings fully compatible with iMovie.
Guide: Converting MTS to Apple InterMedite Codec .mov for iMovie
Step 1. Install and run the top MTS to AIC MOV converter from Brorsoft on you Mac, and then load your .mts files to it.
Tip: Tick the box "Merge into one" on the main interface.
Step 2. Choose iMovie and Final Cut Express --> Apple InterMediate Codec (*.mov) as output format on the dropdown menu which you can get by clicking the Format bar.
Tip: Adjust video and audio parameters on the Profile Setting as you need. We recommend 1920*1080 as video size, 30fps as video frame rate to get the best video quality.
Step 3. Click the convert button and start transcoding MTS to MOV for iMovie on Mac OS X immediately.
When the conversion is done, you can get the AIC .mov video from the output folder you set. Now, import the converted MTS files to iMovie for editing freely.
Importing and Editing M2TS files in iMovie
Converting MTS to iTunes friendly MP4/MOV format
Convert .MTS to ProRes on Mac Mavericks for FCP users
AVCHD corrupt folder structure crashed in iMovie/FCP- How to fix