Recently, I found many people are annoying at converting DTS in MKV files to AC3 without any command line or boot camp. The article will show you a good solution to make it according to my own experience.
First, you should choose a reliable Mac MKV converter which allows you to convert DTS to AC3 without any problem. After a lots of Google search, an all-in-one program called Moyea MKV Converter for Mac does the job perfectly. It not only can convert MKV to any other popular video/audio format (MP4, FLV, 3GP, MPEG, VOB, MOV, F4V, MP3, AAC, AC3, M4A, VFW, etc) but also supports converting MKV files maintaining 5.1 channels.
Additionally, it is a wonderful editor. It offers some special editing functions so that you can improve and perfect your MKV files.
After launching this Moyea MKV Converter for Mac, just follow the below to convert DTS to AC3 on Mac in a short time.
Step 1: Click the “Add” button to add your MKV files into this program.

Step 2: Select output format and location
Once all the MKV files are loaded, you can choose output format from the drop-down list “Format” as well as set the destination folder from the “Browse”. If not, the output files will be saved in the default path automatically. Here I just choose AC3 as example.

Step 3: Click the “Convert” button to start MKV conversion.

As long as the MKV DTS to AC3 conversion is finished, you can get the AC3 files from the destination folder you set.
PS: This Mac MKV Converter is an all-in-one MKV tool. So you can make full use of it to meet your needs
Good luck!

